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JDOFMEMI
01-26-2012, 06:44 PM
I was browsing the web and come accross this. Allegedly happened when the steering wheel holder decided to downshift from 6 to 1.

Kind of hard on engines that way!

http://www.miningmayhem.com/2012/01/downshifting-in-793.html

willie59
01-26-2012, 07:07 PM
They should draw a picture of a 793 on steering wheel holders final paycheck.

buckfever
01-26-2012, 07:28 PM
I cann't even imagine what that sounded like when it came appart.

Lee-online
01-26-2012, 08:11 PM
If the trans is thrown into 1 or even R from 6th, it won't shift down until all the requirements are met.

I think its a BS storey.

alco
01-26-2012, 08:29 PM
I'm with Lee on this one. Unless there's some sort of problem with the truck, they won't downshift like that.........trust me, I've seen it attempted first hand.

wosama931b
01-26-2012, 08:49 PM
Whats the use of going through all the other gears anaway; ha ha, I hope the guy is ok, and seat straped in when that happend.
Sometimes that backlash puts a lot of stress on the gears, yes i have torn up some stuff on down shifting when i was a young hot rod. Sama

JDOFMEMI
01-26-2012, 09:04 PM
As pointed out by Lee and Alco, they are not supposed to be able to do that. I only passed on what was posted, but from the evidence, something serious happened.

I have seen a 6V-71T Detroit do similar things when the rear transmission, which it was attached to, failed to upshift from second while the front went clear to 6th in a scraper. I picked up pieces of connecting rods off of the road, then followed the oil trail to the dead soldier. It had enough holes in the block you could stick an arm in one side and out the other. Shame I can't find the pictures. It also should not be able to do that, but with the failure of a $3.00 part let things come unwound.

alco
01-26-2012, 09:21 PM
Yeah, you can only go by the story presented. The biggest problem I have seen with that site, is that they seldom have the right story.

Nige
01-27-2012, 07:18 AM
If the trans is thrown into 1 or even R from 6th, it won't shift down until all the requirements are met.

I think its a BS storey.I agree. A correctly-functioning downshift inhibitor will not allow any downshift if it results in the engine over-revving, however .................... read on.

On 1HL 793B & 4AR 793C trucks back around the 1999-2000 time frame when Cat still used the non-programmable EPTC-II transmission control instead of the ECM used in the latest trucks it was discovered that there was a "hole" in the software logic that if the truck even briefly lost transmission speed sensor signal and then the signal came back again a couple of seconds later at or close to a zero value and the transmission control judged said signal to be genuine (but it was actually false) the control would then call for a downshift to 1st speed. In this case the shift cane was still in 5th or 6th speed, it didn't need the operator to touch it. The clue was to look for a brief MID-27/CID-672/FMI-11 event registered in VIMS. Generally the cause was a damaged or worn transmission wiring harness connection to the speed sensor interrupting the signal. We had a number of them happen, usually it resulted in an engine overspeed up around the 3000RPM mark but never causing the type of damage seen in these photos. In every one of the 23 cases I have in my files the engine was pulled and we found valve/piston hits, bent rods, etc. 2 engines out of the 23 had a rod through the side. Expensive failures ..............

Eventually Cat fixed the hole in the software logic by re-writing it including an additional step that was a ratification check between engine RPM and transmission speed (they called it TOSRAT) that had to be satisfied before the control would call for a downshift to prevent these unwanted shifts. We had a guy from the factory installing new chips in EPTC-II modules in our shop for the best part of a month. I reckon he must have re-chipped about 300 units all told. In truth it was a mainteance issue because some of the wiring harnesses I saw were in such a bad condition with fretting and broken wires repaired by twisting them together and wrapped with tape it was a wonder they worked at all.

So regarding the OP story and the photos I guess it's a case of what exact vintage of truck is involved, and if it's a 793B or an early C model with an EPTC-II there is a possibility the story has a grain of truth in it, but it would still require that the truck was fitted with an EPTC-II that was never upgraded 10 years ago - Cat changed them all at that time, or at least re-chipped them. However we never saw an engine with this amount of damage so in that respect it does not make sense.

scholzee
01-27-2012, 09:55 AM
I am a newbie to big mining equipment. I thought the trucks have electric motors driving the wheels and the engines more or less just turn an electrical generator. Is there some connection that uses the engine in braking like a typical automobile ? I know when you downshift a car it can load the engine and help in engine braking, how is the connection from the wheels to the engine on these big trucks ?

Andre Grondin
01-27-2012, 10:22 AM
Hi !

easy removal of parts , almost no need of any big tools !! no worry about measuirng if any in spec !! replace the whole
thing !! quick decision !! lol

Nige
01-27-2012, 12:33 PM
I am a newbie to big mining equipment. I thought the trucks have electric motors driving the wheels and the engines more or less just turn an electrical generator. Is there some connection that uses the engine in braking like a typical automobile ? I know when you downshift a car it can load the engine and help in engine braking, how is the connection from the wheels to the engine on these big trucks ?Cat trucks are all 100% mechanical drive, except for the new model 795F that has electric drive.
Electric drive trucks retard by turning the wheel motors into generators and loading them into a large resistor grid. Mechanical drive trucks have the engine physically connected to the transmission via the converter lockup clutch plus they use multiple oil-cooled disc brakes on all 4 corners to also assist with retarding.

CAT793
01-27-2012, 04:48 PM
Funny how us boys always love a Engine POP........... Good for a giggle!!!!!!!!

The story is 100% LEGIT! and Nigel has most of the YARN nailed.

Will add a few things that I believe to be true. This truck was before the 1HL and 4AR models it is actually a 3SJ serial No. So it was before the EPTC-II (just called EPTC) and it was completely CAT's fault (dodgy Flash File). This happened in Indo too if I am not mistaken.

This failure could be as simple as a finger loose Deutsch Military Connector at the 3E-6955 Speed Sensor on the Tranny. We continued to suffer the Harness/connector issue long after they Re-wrote the software but the result was way less dramatic. They just held gears!!!!

Nige
01-27-2012, 05:39 PM
PM me an e-mail address and Iīll e-mail you a copy of the presentation we did to Cat back in early 2000 about the failures we saw. That is deffo chapter & verse because not only does it have all the affected Serial Numbers in it and all our downloaded information from the elctronic controls, it also contains Catīs explanation for what went wrong. We only had 1 x 793 3SJ prefix in our area but that truck never experienced this problem. All the affected trucks were either 1HL-prefix 793Bīs or very early 4AR-prefix 793Cīs, in the 4AR001xx range.

I heard of the same issue occuring in Indo & Oz, not sure about N. America. For sure there were a number of Product Programmes as a result of it .......... focused people's minds wonderfully for a short space of time.

Just had another look at the photos and it is definitely an early engine because it has 2-piece pistons in it, not the later one-piece forged jobbies. However I can't see a clear view of an injector anywhere which would prove whether it was an MUI engine from a 793 or an EUI from a B or C truck.

rare ss
01-27-2012, 10:26 PM
there was one which let go at Sunrise Dam with the same sorta results, rag was left floating around inside the sump after a midlife, let go about 10m up the base of the pit

Gavin84w
01-28-2012, 06:26 AM
These pics are fron Canada, in the tar sands and are quite old, over 10 years i am lead to believe. Pretty sure it is a 3SJ but if it is not then definently a 1HL, they had lots of 793B in the Tar sands.

CAT793
01-28-2012, 06:42 AM
Totally trust your call mate! You appear to know the LOHT range well!

I Am 100% sure this truck is not a 4AR for these reasons:-
* The shape of the Converter housing (this Truck still has the shallow sump as the reservior is out near the hydraulic tank).
* The rear "Tower of Power"...... 4AR had a turbo Cradle instead.
* See the small rim on the piston so it is a "A" Series Engine. "B" series has a 20 mm shoulder in the crown.
* See the additional oil cooler on the inside RHS Chassis Rail for the hydraulics.
* In picture six you can see the ADEM 1 ECM with the removable cover for the EPROM.

So it is most likely a 1HL as you say as 3SJ were MUI with a Woodward Governor unless Repowered??? I worked for the dealership in OZ when the SL came out that I think you are going to share and at our site all the EPTC came as complete ECM with the NEW Software Installed (144-1974 if I recall correctly as they had to have the 144-0178 Speed Sensors fitted at the same time to remove the Erroneous MID 027 CID700 FMI 11 and the LUC Disengagement.

Look forward to reading the SL on the Rework!

Nige
01-28-2012, 08:51 AM
The failures we had were both on ADEM-I & ADEM-II engines. I heard that a lot of dealers were shipped complete replacement EPTC-II units but we had so many of the things that the factory flew a guy down with a box of EPROM chips and he re-chipped then resealed and etched the new Part Number on every one. After that each one had to be tested on a "black box" he brought down with him to check functionality before being released to the field.

spanner
01-28-2012, 06:09 PM
I have seen many engine failures for all kinds of reasons but I have never seen one munch itself that completely. It had to have suffered a catastrophic failure at speed and then continued being driven by the wheels until it dismantled itself. A wrong downshift signal sounds like a good explanation but as Nige says, doesn't usually result in that much destruction. More like a couple of pounds of C4.

Dozerboy
01-28-2012, 09:56 PM
I don't see that much damage happening from a down shift.

Gavin84w
01-29-2012, 07:41 AM
Slightly downhill loaded at speed will take the truck quite a ways to stop as compared to on a 10% ramp in 1st gear going up, could be 3 to 4 truck lengths by the time the operator gets a handle on it, lots of carnage can happen pretty quickly.

Catman4
04-25-2012, 07:53 AM
There were also failures with the quill shaft that drove the TOS chopper wheel which resulted in loss of vehicle speed signal to the ICM ECM.
I have often wondered if in slippery underfoot conditions and heavy braking that results in the rear wheels locking up whilst truck is still at speed the xmsn can then downshift and if brakes are then released with truck still at speed will xmsn be able to upshift fast enough to prevent engine overspeed?

Nige
04-25-2012, 09:12 AM
A loss of TOS signal would not in itself cause a downshift. It would generally cause the transmission to hold in gear.

The slippery underfoot conditions you describe would not in my opinion cause major problems with engine overspeed, if at all. Could the engine overspeed for a split second as the transmission was struggling to upshift fast enough to keep pace with the sudden increase in wheel speed..? Quite possibly. However I don't think that would cause prolonged (5 seconds or more) engine overspeeds at 3000+ RPM which is what we saw. I'll repeat that even the engines I saw overspeeded in excess of 3000RPM caused by unwanted downshifts did not destroy themselves like that one did. The worst I saw was one rod out of the block.

If you remember the first generation of ARC systems would generate very short engine overspeed events if a loaded truck transitioned from level ground to a downgrade, or even worse transitioned over an uphill crest and straight on to a downgrade as the ARC struggled to keep up with the truck ground speed. The solution was to give it a sniff of the manual retarder as the slope was transitioning to downgrade, then release the manual retarder as soon as the ARC was in full control. Latest HARC system has been sharpened up a lot response-wise and that doesn't happen.

Catman4
04-26-2012, 01:15 AM
Mr 793 can you clarify with 793C the 4AR / 4GZ what the go was and correct any errors ie

793 3SJ 3516 MUI, ICM EPTC, AETA ,VIMS ( interface boxs) version?
793B 1HL 3516EUI ADEMI,ICM EPTCII ,ARC, VIMS ( interface boxs)version?
793C 4AR ??
793C 4GZ 3516B ADEMII,ICM Trans/Chassis Control ,TC & Trans combined with TC sump,Intergrated Braking Control (ARC and Traction),Ground Speed RAX,E Hoist,VIMS version 9?
793D FDB 3516B HD ADEMIII, ICM Trans/Chassis Control, IBC, Continuous RAX, VIMS version?
793F C175,EPTC,Mesabi Radiator,4 bar Rear Axle to name a few

Nige
04-26-2012, 09:46 AM
OK, I'll have a punt .........

Just a comment regarding VIMS. I'll refer to early 1st generation VIMS systems that had separate Main module & Interface modules as VIMS 68k because that was the processor size. This system was only programmable via the VIMS download cable. It started as VIMS 6.X and ended up as VIMS 9.X depending on vintage. The hardware for these systems was often known as 2.0 or 3.0 depending on vintage.
2nd generation flashable "ECM-style" version of VIMS is commonly known as "VIMS ABL", again because of the processor. Most 68K trucks on the market can be upgraded to ABL to take advantage of the more powerful processor and the possibility to monitor about 10 times the number of channels that 68K was capable of doing. VIMS ABL uses what's known as 4.0 hardware.
The latest version of VIMS (introduced on 793F, 795F, & 797F) is known as "VIMS 3G" (3rd generation) and uses an A4-N4 ECM.

793A 3SJ - VIMS was not around when the 3SJ trucks were built. All were produced with EMS. Some were retrofitted to VIMS at the same time as the engine was upgraded from MUI to EUI. Also can retrofit RAX lubrication.
793B 1HL - EMS was standard, VIMS was an option. Original production split about 50/50, again some trucks were later retrofitted to VIMS 68K. VIMS on these trucks can be updated from 68K to ABL using a retrofit kit. RAX lubrication introduced using a pump driven off the differential.
793C 4AR - 3516B EUI, ADEM II, ICM, EPTCII, ARC, AETA, RAX lubrication, VIMS 68K was standard fitting. VIMS on these trucks can be updated from 68K to ABL using a retrofit kit.
793C 4GZ - 3516B EUI, ADEM II, ICM, EPTCII replaced by flashable Power Train ECM, IBC (combined ARC/AETA in one ECM), RAX lubrication, VIMS 68K, again can be updated to ABL. 3516B HD "long stroke" engine option was introduced with this model. Low altitude operations use the long stroke engine and 4 x single stage turbos, high altitude arrangement still has to use the short stroke engine and compound turbocharging with wastegate.
793C ATY - 3516B EUI, ADEM II, ICM, flashable Power Train ECM, IBC (combined ARC/AETA in one ECM), RAX lubrication, VIMS ABL. Same engine options for low/high altitude operation as 4GZ. Road Analysis Control (RAC) option introduced for the first time.
793C CBR - Identical to ATY but equipped with sound deadening (aka Ultra-Quiet Truck)
793D FDB - 3516B HD or SS EUI (depending on application) ADEM III, ICM, flashable Power Train ECM, IBC (combined ARC/AETA in one ECM), RAX lubrication, VIMS ABL. Optional RAC.
793F SSP - C175 ADEM IV with 4 x single-stage turbos, ECPC transmission clutch control, flashable Power Train ECM, IBC (combined ARC/AETA in one ECM). ARC RPM is now adjustable instead of fixed @ 1950 RPM as with previous models. 797-style external forced RAX lubrication, VIMS 3G. All ECM's on the machine (not just the engine) are ADEM IV. 797-style rear 4-link axle link system. Mesabi radiator now standard.

Catman4
04-27-2012, 03:16 AM
You no doubt have a " penchant " for the 793 ! Assume you are also dealer employed.
I was aware of the IRM that covered the VIMS upgrade from 68K to ABL .
As I recall it listed parts required depending on whether wide or narrow cab......whats the go there did narrow have small buddy seat and wide
have full size seat ?
Also the term ABL I believe it is just some type of computor lingo ?
Its interesting that the VIMS upgrade was made in conjunction with a s/n prefix change.
We also have 789C 2BW and the VIMs upgrade and ARC/HARC was purely handled by s/n range.
With the 793 combined trans & TC with TC sump.
We have had two failures on 793F where leaking trans clutch piston seals allow excessive trans charge pump flow to dump into trans case.
The 793F has a low oil level sensor in the TC sump ( I think 793D also has it ?) and the problem is first made apparent by the low oil level sensor warning of the drop in oil level in the TC sump. It seems the scavenge pump is not able to remove all the oil from the trans case. But when checking the flow specs of the trans charge,scavenge and lube sections of the pump the scavenge pump should be able to remove the combined trans charge and lube flows.There must be a delay when the scavenge pump changes from pumping partial flow to full flow.
The 793C we have dont appear to monitor TC oil level and so I dont know what happens when they blow the clutch seals blow do you have any experience with this?

Nige
04-27-2012, 07:55 AM
The difference in the Upgrade kit is down to the mounting of the former VIMS main/interface modules in the cab between the "old" generation cab with wind-up windows and the new generation cab with electric windows. The older cabs would be 785B 6HK, 785C 1HW, 789B 7EK, 793B 1HL, & 793C 4AR. The new cabs would be 785CHAA 5AZ1-263, 785C APX1-450, 789C 2BW1-302, & 793C 4GZ. The first 785C & 789C were actually built with 68K but soon went to ABL, hence the Serial Number break. 793C 4GZ was built with ABL from the first machine.

The only difference between the upgrade kits is the actual mounting bracket for the new VIMS ECM and the wiring harness Part Number. Both harnesses have exactly the same wires just some of them exit the harness at slightly different places between the 2 cab generations to accomodate different bracketry.

If you have leaking transmission clutch piston seals on any clutch you should be able to see it coming even beforehand by trending Clutch Slip time in VIMS. You'll start to see signs that one clutch is "off spec" compared to the rest.

CAT793
04-27-2012, 09:36 AM
Clearly Nige has it covered. I will ADD a few personal Experiences:-
793 - 3SJ - with the 3516 MUI have a mechanical Woodward Governor. Serrita in the US still has these running with 110 000 Hours on the SMU. My FIRST exposure to a "LHS Dead Chicken" Replacement.
793B - 1HL - Have a FIXED Nose Cone sides. Cant remove the Radiator as a Module. Thermostats on the Aftercooler Circuit. The Engine has a Rear "Tower of Power" like a D11R and the Steer Pump is driven off this not the Pump Drive. ADEM 1 Software Updates used to be a EPROM in an Envelope with the FLASH FILE loaded. Converter/Tranny Oil seperate. Share a Converter Slug with a 9YF 994. Lots of Steel Tubes in Circuits and few Hoses.
793C - 4AR - (Last of the Yellow Cabs) All we ever did was Head Gaskets, Accessory Drives, Cams & Followers, Brake Packs and F/D. Switch the Circuit Breaker OFF for the SMART Wastegate and you would see 45 PSI of BOOST. Literally SMOKE the Rear Tyres on Concrete with 46/00R57. I have a FEW with 86 000 Hours under my watch. My first Exposure to HD Upgrade.
793C - 4GZ - (First of the Black Cabs)The ECM Stack behind the CAB was a MESS. Emergency Retarder was now a Tredle Valve not LHS Steer Wheel. EPTC II is now a MAC Controller (As in it no longer has a LED Panel for Diagnosis - ONLY ET for checking Ground Verifiers etc). When upgrading VIM 10.52 have to BACK Flash it with 10.4 in order for it to load.
793C - ATY - Pretty Solid Truck and MOST Bugs ironed out except CAB DISPLAY ERR. First 93 with a Emergency Brake Modulation.
793C XQ - CBR - Had 2x D10 Cooler Modules side by side with Hydraulic Fans. I have seen some with the Air Boxes (Mt Keith) with the Air Boxes mounted to the Side (Not the Front).
793D - FDB - Put back into Production after the GFC. We are still delivering them NEW now (Up to FDB01500 IIRC). Extra Disc and Plate in the Converter for LUC to handle the extra 100 HP. BC Pump inside the Hyd. Tank. Comman Rail Steering/Fan. MA1, MA2 and MA3 Option for Down Hill Haul, High Speed Haul, HAA. Rubbish AMOCS Radiator. After FDB01230 they were Factory 3516C.
793D XQ - 5 Tonnes of Sound Deadning, Covers, Guards, Panels, Nappies etc.
793F - SSP - NONE in our Patch yet. NO more "Air Over Hydraulic" Brakes. HARC.
793F XQ - SND - We have to First Production Truck in the World (SND00100). Around 1000 Hours (Few Fuel HPCV Issues and a Tranny clutch seal).
793F CMD - Autonomous Trucks. WAVS, COIDS, COMMAND ect.....and NO AM/FM or Air Con Necessary!!
793F AC - Cant be FAR away.....

On the Tranny Clutch Pack Piston Seal Diagnosis :- Disconnect the 3 Solenoids (PB On), Hook Gauge to PMP Pressure on your Trans Pilot Control Valve. Rotary Spool from N1, N2, R, 1, 2, etc and watch the Pump Pressure. Good Seal and the Modulation is Instant. Poor Seal and the Pump takes a while to Recover the Flow Loss Filling the Clutch. If they are bad enough you can pick it looking at the Main Drive Shaft on Shift (It will Rock backwards and Fowards slightly).

Nige what was the difference between CMS and EMS?

Nige
04-27-2012, 12:40 PM
Only the title AFAIK. Look at a 992D 7MJ O&M and it says CMS (Computerised Monitor System), a non-VIMS 9YF 994 or a 3SJ 793 and it says EMS (Electronic Monitor System). Both work in pretty much tne same way even though certain modules/parts may be different numbers.

Agree with you the ATY Cab Display Error was a pain until the fix was widely published and the ECM Wash File became available.

I'm just hoping Cat hasn't fcuked the 789 up. We've got 15 new 789D's coming soon ........

793F I don't think will go AC. The additonal 10-15 tonnes empty truck weight for the AC Drive Components will be just too heavy to permit the truck to stay in the 240 ton class like the present 793F.

793F AC Drive
04-27-2012, 04:31 PM
I wouldn't bet money on that Nige. Field Follow is in progress.

Nige
04-27-2012, 07:06 PM
Won't be the first time I've been proved wrong, most likely won't be the last.........

Gavin84w
04-28-2012, 10:51 PM
I wouldn't bet money on that Nige. Field Follow is in progress.

Depends what odds you are offering. What odds would you give me Unit Rigs will be Cat powered soon?

CAT793
04-29-2012, 05:46 AM
What are the ODDS that CAT will "Teir 2" the 3516 HD.......

I though 3500 would be dead in the water after the C-175 was released......now I believe they will be still developing them in 10 years time....ACERT fuel system, DPF???

Nige
04-29-2012, 09:40 AM
3500 is still well alive and kicking AFAIK, even though it's allegedly yesterday's technology. Don't just think machine engines, think industrials & gensets as well. Machine engines will be but a small fraction of 3500 sales.

793F AC Drive
04-30-2012, 11:44 AM
I'd say odds on both are very good.

Nige
04-30-2012, 03:08 PM
OK, a question. What going to be the preferred method of getting a 793F truck equipped with electric drive back to a minimum of "240-ton class" (218 metric tonnes) payload, Ultra-light bodies..? With the electric drive I'm sure that the empty weight of the truck will increase by about 15 tons.

793F AC Drive
04-30-2012, 03:13 PM
I can't speak to the details of the strategy, but the current FF unit is running a standard coal body, and it will easily hold the target payload. I have also seen overloads of up to 297 tons.

Nige
04-30-2012, 06:10 PM
That's fine talking about a coal body, I can remember the first 797 coal bodies and they were monsters. What about one for rock ....? I take it the FF unit must be up in Powder River somewhere..?

Gavin84w
05-01-2012, 05:44 AM
I'd say odds on both are very good.

I better get a few bucks on it then!! Will be interesting to see how they diet the 793F AC. It is clear from the first attempt you can,t just take a MD chassis and electrify it, needs more homework than that. Personally i think the 3500 getting a new lease of life with Tier upgrades has come about with the purchase of Bucyrus giving Cat a big population of trucks they can offer retrofit upgrades to and then the averagedebut of the C175 so they don,t want to muck up bread and butter model trucks like the 785 & 789 with the C175 so they then can benefit from Tier upgraded 3500.

The 3500 will go a long way yet and it,s a pretty good deal for an engine 30+ years old in design.

793F AC Drive
05-01-2012, 10:32 AM
That's fine talking about a coal body, I can remember the first 797 coal bodies and they were monsters. What about one for rock ....? I take it the FF unit must be up in Powder River somewhere..?

Rock body just hit the dirt last week, and is using a standard body with great results as well. As far as the location, good Guess Nige. I guess this isn't your first rodeo.........

Nige
05-01-2012, 12:04 PM
Rock body just hit the dirt last week, and is using a standard body with great results as well. As far as the location, good Guess Nige. I guess this isn't your first rodeo.........Coming up to 40 years, man & boy. Most of it around big yellow iron. So I guess you can say it isn't my first rodeo. I've got to the point now where I'm thinking of making a career of it ...... :cool2:cool2

Last time I was up there was a while ago, Black Thunder to be exact. We were tearing down some 793C ex-rental units that went way South from there. December it was, and fcukin' cold.

Catman4
05-09-2012, 08:07 AM
What are the ODDS that CAT will "Teir 2" the 3516 HD.......

I though 3500 would be dead in the water after the C-175 was released......now I believe they will be still developing them in 10 years time....ACERT fuel system, DPF???

I have seen a photo of a 3500 in Cat lab test cell complete with common rail fuel system fitted up. The high pressure fuel pump (HPFP) looked like the current Woodward HPFP used on C175 engines.
The 3500 was called 3500 NGCR ( Next generation common rail).
Its interesting to consider the reason for hanging in there with 3500 given the C175 is very similar displacement and were always explained / introduced as the replacement for the 3500 platform.
Perhaps the economics of shutting down that production capability when there will be increased demand ( Bucyrus and global mining expansion ) for this sized engines platform dictated this.

Catman4
05-09-2012, 08:22 AM
Do you have any info on the 793F FCV failures / problem ......were they engine cranks but wont start issues? Also the tranny clutch seal - was it identified by trans low oil level alarm coming on as I made mention in previous thread?
793F tranmission hyd controls are ECPC not ICM......its all done with ET and excess clutch piston seal leakage is confirmed when the ET automated transmission fill test aborts on a particular clutch.

orville
05-15-2012, 09:02 PM
This is kind of not on topic, but could anyone tell me how many yard loader a 793 is? The job I am on we used a 793 with forks to move a large steel assembly that weighs close to 20,000 LB's, made the rear wheels kind of light. I think it is a 5 yard machine, am I right?

Gavin84w
05-16-2012, 06:19 AM
This is kind of not on topic, but could anyone tell me how many yard loader a 793 is? The job I am on we used a 793 with forks to move a large steel assembly that weighs close to 20,000 LB's, made the rear wheels kind of light. I think it is a 5 yard machine, am I right?

793 is a 240 ton capacity Cat dump truck, well at least the one we are talking about here is.

orville
05-16-2012, 08:46 PM
793 is a 240 ton capacity Cat dump truck, well at least the one we are talking about here is.

I can't remember numbers, Cat has so many of them. Today I wrote the number down, it is a 972G rubber tired loader. For some reason I thought the machine in this thread was a loader. But if it was it would have been in the wheel loader section of this forum. I apologize for my ignorance.

Ross
05-23-2012, 12:05 AM
Do you have any info on the 793F FCV failures / problem ......were they engine cranks but wont start issues? Also the tranny clutch seal - was it identified by trans low oil level alarm coming on as I made mention in previous thread?
793F tranmission hyd controls are ECPC not ICM......its all done with ET and excess clutch piston seal leakage is confirmed when the ET automated transmission fill test aborts on a particular clutch.

It weren't the control valve it's the pump that's going on the fritz. 50 grand a pop.

Those 793F's are 80 BCM cycle.

The tranny is pro port control. You need to alter pressure via the pro pops before doing the fill test. An indication of failure before the triple fill would begin.

So much going on here I couldn't even comment!

Edit: Thanks for replying to my email Nige!