cat 735 won't shift out of first gear

[Digger8989]

Did this fix the problem?

Hey,
Wondering if the new solenoid fixed the problem ?

Well I went directly to the lock up solenoid and valve to check the ohm's. It measured a lil high but still in range. So Itook off the whole solenoid to check ooperation of the valve and at first it was somewhat stuck in place, after it came free I checked the ohm's and it read way out..like 4.00 high. It said 8.7+/- .40..it reads 12.5 now. I figured what the heck and hooked it to 12v and nothing,hooked it to 24v and nothing. I ordered a new solenoid from Thompson cat and it will be there in the morning. Hope that fixes my problem and thank you so much for your help!

 

[Warddozer]

Hate to Bring up an old thread I just bought a cat 725 2006 model. Driving it to job site went about a half mile transmission filter light came on. Went back to yard and changed it. It shifted fine a little hesitant but shifted. I now have reverse intermittently but it locks in strong and only have first gear on forward shifts to second on display but nothing is there?? I have re-calibrated the clutches. It is displaying codes of
Turbo pressure sensor
Throttle positioning sensor
Fuel level sensor
Transmission temp sensor
Code that first shows up on start up is
273-0138 which I cannot find out what it means any ideas?

 

[Nige]

Post a Serial Number for better information. I can check & post the diagnostic procedures for the 4 codes you mention above when I get into the office tomorrow.

 

[Warddozer]

B1L699 the last code 273-0138 is the one I am having trouble with. Thank you

 

[Nige]

B1L699 the last code 273-0138 is the one I am having trouble with. Thank you

T273-0138 is actually the Part Number of the electronic indicator panel in the dash. When you first turn the key on and it boots up it is programmed to display the Part Number during the bootup sequence. BTW there is an updated panel available, Part Number 287-3247.

Regarding the other four codes, please can you post details of what is displayed. e.g. something like 091-08 or similar. It will help to identify the correct troubleshooting procedure.
Also have you confirmed that those four codes are Active, and not simply Logged meaning that they were there at one time but are not there now..?

Turbo pressure sensor
Throttle positioning sensor
Fuel level sensor
Transmission temp sensor

 

[Warddozer]

Yes they are active nothing else comes up on dash I am using cat et. I will be getting in those sensors later today because of my location I ordered them and will test and replace them as I go return what I don’t need. I am just wondering if the throttle positioning code can kick it into a limp mode only leaving first gear? I will update
Thanks again

 

[Nige]

Rather than replace sensors wholesale to "fault find by substitution" would you not be better advised to go through the Troubleshooting Procedure for each of the Active Diagnostic Codes that you have..? Some if not all of the issues could be down to a bad wiring harness or connector. Swapping sensors ain't gonna fix that........

If you post the Diagnostic Codes in CIDxxx FMIyyy form I'm pretty sure that I can round up the correct Troubleshooting procedure for each one of them.

 

[Warddozer]

Active codes
Engine side
1589-3 turbo inlet pressure voltage above normal
91-8 threottle position sensor abnormal frequency, pulse width, or period
96-3 fuel level sensor voltage above normal

 

[Warddozer]

Performed throttle position test
O% at idle
100% at wide open throttle

 

[Nige]

There's your problem (I think). The throttle sensor signal needs to be between 7% (Idle) and 95% (WOT). Procedures attached.
A suggestion. Pay particular attention to every electrical connector you open, especially the big ones. Get in there with contact cleaner big style.
The turbo inlet pressure sensor shows as CID 275, but the procedure should be the same although you might have to pay attention to wire numbers in the harness. That sensor is part of the signals that measure air filter restriction (and control engine derate). Maybe that's where your issue lies..?

 

[Andry]

Hi, everybody! I have very old dumper cat 769 and there is a problem - works only 1st and reverse gear. Mechanics says it's electric trouble, but wires, selector and gear module works correct dye to diagnostic panel. Solenoids are clicking when current on.

 

[Andry]

There is such diagnostic dashboard, who knows, is a colour of leds has the meaning?

 

[Nige]

First thing. Start with a Serial Number please.

That photo looks like an EPTC-II. Does the truck have an electronic transmission output speed sensor.? It will be located on the front of the transmission right at the bottom, probably behind a metal guard. But you will recognize it because a wire harness will appear from behind the guard.

 

[Andry]

This is serial number. I'll check speed sensor tomorrow. Thank you!

 

[Nige]

So you have a 769C. That will have an electronic speed sensor fitted.

Did the problem of not shifting past 1st speed forward develop suddenly or has it been happening on & off for a while.? If it was sudden I would suspect that either the sensor has failed or possibly a cut wire in the harness to it. If there is a cut wire it ought to be easy to spot.
If it has been happening intermittently for a while I would be looking for a bad connector (corrosion.?) somewhere between the sensor and the electronic control in the cab.

I need to look up in the system what the LED lights on the control indicate.

 

[Andry]

There is a red led of sensor at diagnostic panel. But i don't know what sensor. It's glowing all the time

 

[Nige]

Hopefully I’ll get a few minutes to jump on the system and check out the LED meanings later. I know I said before that at first glance it looked like an EPTC-II, but thinking about it I’m not sure that the smaller trucks like the 769 didn’t have a slightly different transmission control module, because your photo looks somewhat different from the modules I remember on the big trucks.

 

[Nige]

OK, so what you have is a 1st Generation Electronic Programmable Transmisison Control (EPTC) as opposed to the 2nd Generation EPTC-II.
Do you have an Electrical Schematic for the truck.? - Because you are going to need one to do a number of the tests.

Basically your LED lights are as follows, starting from the left of your photo.
5 lights showing the transmission control lever position - in other words which transmission clutches the lever is commanding to be engaged.
5 lights showing the signal from the Actual gear switch mounted on the rear RH side of the transmission - in other words which transmission clutches are ACTUALLY engaged.
1 light for the transmission speed sensor pickup signal.
1 light for the retarder system active.
3 lights. One for each of the upshift, downshift, and torque converter lockup solenoids.

 

[Nige]

Have you tried shifting the transmisison manually using a pair of vice grips on the shaft on the end of the actual gear switch on the side of the transmission.?
To do that you ideally need get the rear of the truck up on stands and remove the tyres - it can get more than a bit interesting sitting on top of the transmission with the dump body raised and the rear wheels spinning at high speed right next to you....!!
If you do this you need to pay particular attention to ensure that the front wheels are securely blocked against unwanted movement and that there is no possibility that the truck can slip off the stands holding up the rear end.

 

[Andry]

I think, Electrical Schematic i have is not actual, because i found some inconsistencies between diagram and connections.
I noticed, when dumper was in motion, that leds of actual gear switch were like 4 gear is opereting, but real is 1 gear... It means leds are changing, but gear is not. Does colour of leds mean anything or not? Thank you very much for assistance