988H wheel loader transmission and torque conveter problem

Good day wheel loader gurus

we have 988H wheel loaders purchased in 2010 . we operate in a coal environment. our loaders are experience recurring transmission system and torque conveter failures. these are mainly characterized by loss of pressure on the clutches and presence of metal filings. kindly help with the causes of these challenges and what we may do to rectify the problem

thank you

how are they being operated? I remember having the same transmission come back for a 988h several years ago that one of our guys built with the customer saying it was our fault, until one of our field guys getting footage of them running the equipment really hard and getting the rear end into the air frequently, overloading, running into the pile at high speed, all sorts of stuff

catfixer said:

how are they being operated? I remember having the same transmission come back for a 988h several years ago that one of our guys built with the customer saying it was our fault, until one of our field guys getting footage of them running the equipment really hard and getting the rear end into the air frequently, overloading, running into the pile at high speed, all sorts of stuff

Click to expand...

we use our earth moving machines for bunkering and stocking of coal. we have bowl scrapers , front end loaders and bulldozers. sometimes the front end loaders push the coal into the bunkers when the dozer is overwhelmed. could that be the reason??

By the sounds of your post you have more than one 988H. How many machines in the fleet..?
Are all the loaders affected the same way with premature failures..?
Do you perform oil sampling on the transmissions and if so has that given any indication of problems before failure occured, or even after failure..?

we have 2 bowl scrapers , 1 dozer and 3 front end loaders. with one 988B and two 988H. the 988H are the only ones being affected.
we take oil samples on every 250hr service intervals
in some instances there are metal filings in the samples before failure and in some the oil turns black and will be smelling.

in some instances there are metal filings in the samples before failure and in some the oil turns black and will be smelling.

Click to expand...

Is this what happens to the transmission oil on the 988H machines..? Does the transmission oil go black on the 988B machine as well..? You indicate that you take oil samples every 250 hours - at what interval do you change the transmission oil..?

Do any of the 988H operators complain at all regarding "lack of performance" or "lack of pushing power" when the machines are operating normally..? Do you keep the same operator on each machine all the time or do they rotate through the 3 loaders..?

Back to my question above and focusing only on your loaders. So both your 988H machines are suffering the same converter problems regarding premature failures, but the 988B does not. Am I correct..? Can you post the Serial Numbers of the 988H machines please.

Were your failed torque converters rebuilt by the Cat dealer..? If so do you have access to all of their Service Reports (because you have had more than one failure) that indicate the details of the internal damage they found in each of the failed torque converters..? Failing that do you have a list of parts that were put in each converter when it was rebuilt..?

i hope im not butting in nige/cat fixer,
but i may be able to contribute a few cents.
are these the loaders that are part of the machinery that feed the power coal to the crusher furnaces at the power station? and are they zetdc machines or colliery machines?
a bit of background information might be useful for you guys, because correct me if im wrong nige & catfixer, but black oil & filings likely indicate clutch failure/burnt oil from slippage. its an unmistakeable smell.
was it barzem hwange who organised/did the repair?
perhaps if priscila could at least tell you which clutch groups were found to be burnt?

please also verify the type of oil you use on the transmissions, ie is it 15w40 or UTTO-4 30w oil?

another question priscila is are you running coolant or plain water in your radiator systems?

the other thing you guys should know about that place is it is hot. an average day is 40 degrees celcius..
do you guru's know of any design difference in the transmission cooling system between the B & H?


ok, so i spoke to a friend who worked at the dealer and they are using CAT oils(sae30) and coolant, so unless someone mixing 15w40 into the transmissions then all good there. plus doubtful blocked cooler is an issue since they use coolant, they are for zetdc/zpc, so good maintenance record, plus they deal with CAT dealer on their repairs.
not fly-by-night's. which is more of a problem sometimes than perceived.
the operators are dealer trained but the mech i spoke to refered to a fair amount of abuse warnings when they hooked up the ET. but he's been away from CAT a bit now, so will ask someone at the dealer tomorrow for a clearer picture. the guys that were there are pretty experienced and reliable.
my friend did mention something about low pressure but i had a bad line and lost the call.
will dig more tomorrow, unless priscila can get those reports first.

Any information is always good.

One thing that crossed my mind (and the reason I asked the question) is if the transmission oil in the 988B was coming our burnt as well as the oil in the 2 x 988H machines..? That would seem to indicate an operational issue. I need to do some digging but I have it in the back of my mind that the 988H had an optional high-ambient temperature cooling package available as an option. Getting Serial Numbers would let us look at the machine arrangements and what attachments they have installed from the factory. If the machines came from dealer stock somewhere else (RSA maybe?) and were not ordered specifically for this particular customer then there is always a chance they were not configured correctly.

I know Wankie and the area around it very well. Using that name dates me a bit I know but in a former life I used to work for the competition at Maamba Colliery on the Zambian side of Lake Kariba to the coal deposits at Wankie and it was just as hot there, especially if the rains failed. We also used to travel frequently to Vic Falls & Bulawayo, and regularly stayed in the lodge at Sinamatella on the edge of the National Park close to Hwange. I've even had the pleasure of travelling behind a steam train from Vic Falls to Byo, in fact not long after Rhodesia Railways became the NRZ. An old friend of mine worked for BOC Zimbabwe in Bulawayo and his brother was one of the game rangers in the Park so we got guided tours in the Park by some of Zimbabwe's best game trackers.

We have a 980g that a few months ago I put the 5th yes fifth rebuilt tranny in. Come to find out on this last rebuild it had a light duty trans we went with the heavy duty. Two of the failures were operators digging in second gear all day and blew up the tq this last on was the reverse clutch pack which I'm still thinking was operator issue because he was in soft ground when it went and I bet digging in first but backing out loaded in second and smoked reverse.

Ryan151 said:

We have a 980g that a few months ago I put the 5th yes fifth rebuilt tranny in. Come to find out on this last rebuild it had a light duty trans we went with the heavy duty. Two of the failures were operators digging in second gear all day and blew up the tq this last on was the reverse clutch pack which I'm still thinking was operator issue because he was in soft ground when it went and I bet digging in first but backing out loaded in second and smoked reverse.

Click to expand...

Getting a little of topic of the OP's 988H. But a n a 980 G going on it's 5th transmission sounds crazy. Were I worked we had a couple of them, both 1999's. One I do have records of it getting a before failure "Rebearing&Resealing at 18,662 hours when it was 10 years old at the same time the engine was done. This was more as a preventive thing than anything else. I was not aware there was a "light duty" version transmission for these loaders, would be interested to know what was different in them.

To get back on the 988H, we also had one of those and 2005 with 14,000 hours on it with no transmission problems other than some leaking hoses and pump seals. But as opposed to the OP's working conditions it seldom sees ambient temperatures above 90ºF(32ºC) and it sits parked from early December to probably mid March due to cold weather and seldom sees more than a 45 hour work week. Almost like semiretired compared to his machines!

I think Nige might be on the right track about looking into the High Ambient Temperature option. If these machines were not spec'd for the conditions they are being asked to preform they are just asking for problems.

It's an unfortunate fact that recent models are much more "on the edge" as regards cooling system performance than maybe the comparable version from 20 years or more ago was. Back then it would be unheard of to have a 2 different cooling packages, one Standard and the other High Ambient but today it's commonplace, even on small to mid-size machines. If the machines were brought to the job site from somewhere else with more temperate climates then it's quite possible they are equipped with Sandard Cooling packages and nothing will fix the root cause of the problem other than some hardware changes.

On the other hand coal dust gets everywhere and unless there is a pretty comprehensive and regular radiator washing programme then the lack of air flow caused by coal dust accumulation could easily cause overheating issues.

Ken, there is a heavy duty transmission for a 980G. It's part of the logging arrangement but IMO should never be required for a normal front-end loader operation.

I have a couple of questions as well on these machines. How many hours on each transmission when they fail? How many hours on the engine? Is the engine cooling fan reversible? Are the machines being run with the engine throttle dogged at high idle all the time and the transmission shifted through it? Are the machines being used mostly for pushing, truck or bin loading, load and carry? What type of tires are being used, L-5, L-3, radial or bias ply? What kind of differentials are installed, standard or limited slip? Are the machines working on an incline?

Howdy, saw this post thought it was proper place to post. Have some 988Hs that were making real fine metal in trans. I just signed up. BXY 004xxx machine's

I guess the first question is what background info can you supply regarding your operation, previous trans replacement/failure history if applicable, oil analysis results if you have them, what work the machines are being used in, etc, etc.

Nige, These machines were bought new by the co. I work for. They are used in a small stone quarry, their main purpose is load & carry shot rock to primary crusher. Machines have just reached a shade over the 9K on the clock, then we started making metal in trans oil. We do a good job with servicing all of the equip. that we have, oil, oem filters & atc. we do the oil samples through our oil supplier, and for the most part they have been good on several occasions. But some how they didn't pick up the high metal count on these machines. First problem on first machine was the impeller clutch valve started hanging up, limiting torq to the wheels, then the oil filter restriction light was starting to come on shortly after, we pulled filter out to look, at first glance there wasn't anything obvious at all. Then I shoved my finger nail in between the pleats of the element to squeeze oil out on to in the sun light, and there it was, it was obvious then. So I pulled out both trans & conv. and sent to the dealer. Sure enough there was an issue, they found with some bellville spring washer that had broke in two, do to two holes the were made into them, for some reason. The new washers do not have those holes now. Long story short, in the last three months I've pulled out the trans & conv. on all three of our machines, to rectify this problem of these transmissions, all under 10K hours. Just thought I would share my experiences. Thanks Nige for asking your questions, your inquisitive mind took the bait of my first post.

we have had similar problems. I think from memory there was a product support program when this issue first raised its head in low hour machines. also there is an software up date as well
mark
A New Spring Is Now Used in Clutch 5 of the Transmission on Certain Landfill Compactors, Soil Compactors, Load Haul Dumps, Underground Articulated Trucks, Wheel Dozers, and Wheel Loaders {3030, 3160} SMCS - 3030; 3160

Wheel Loader:
980GSeries II (S/N: AXG1-UP; AWH1-UP; AYT1-UP)
980G (S/N: 9CM1-UP; 2KR1-UP; 2SR1-UP)
980H (S/N: MHG1-UP; A8J1-UP; KZL1-UP; JMS1-UP)
980K (S/N: W7K1-UP; GTZ1-UP)
988FSeries II (S/N: 2ZR1-UP)
988F (S/N: 8YG1-UP)
988G (S/N: BNH1-UP; 2TW1-UP)
988H (S/N: A7A1-UP; BXY1-UP)

Description of Change: A new spring Is now used in clutch 5 of the transmission on the machines that are listed in this article. This new spring also includes the removal of two holes in the spring. These holes where used for assembly purposes, but are no longer required. The changes incorporated into the new spring will improve spring life.
Adaptable To: The 373-6708 Disc Spring will replace 3P-3635 Disc Spring.
Do not mix old and new springs. Transmission Bellville springs should be replaced as a set.
Do not mix 3P-3635 Disc Spring and 373-6708 in the same pack.
Replace transmission springs at overhaul.
The effectivity for this change is listed in Table 1 Table 1
Effectivity
Model Adaptable To Machines Effective With Machines
826G Series II S/N:AYH1-UP
S/N:7LN1-UP
826H S/N:AWF1-725 S/N:AWF726-UP
836G S/N:BRL1-UP
S/N:7MZ1-UP
836H S/N:BXD1-1207 S/N:BXD1208-UP
825G S/N:AXB1-UP
S/N:6RN1-UP
825H S/N:AZW1-358 S/N:AZW359-UP
R2900 S/N:5TW1-UP
R2900G S/N:GLK1-UP
S/N:JLK1-1128 S/N:JLK1129-UP
AD30 100GA S/N:CXR1-UP
AD30 S/N:DXR1-494 S/N:DXR495-UP
824G Series II S/N:AWW1-UP
824G S/N:4SN1-UP
824H S/N:ASX1-463 S/N:ASX464-UP
834G S/N:BPC1-UP
S/N:6GZ1-UP
834H S/N:BTX1-1267 S/N:BTX1268-UP
980G Series II S/N:AXG1-UP
S/N:AWH1-UP
S/N:AYT1-UP
980G S/N:9CM1-UP
S/N:2KR1-UP
S/N:2SR1-UP
980H S/N:MHG1-UP
S/N:A8J1-UP
S/N:KZL1-827 S/N:KZL828-UP
S/N:JMS1-UP
980K S/N:W7K1-1090 S/N:W7K1091-UP
S/N:GTZ1-376 S/N:GTZ377-UP
988F Series II S/N:2ZR1-UP
988F S/N:8YG1-UP
988G S/N:BNH1-UP
S/N:2TW1-UP
988H S/N:A7A1-212 S/N:213-UP
S/N:BXY1-5215 S/N:5216-UP

New Software May Improve Shift Quality on Certain Machines {3030, 4800, 4808, 7610, 7620} SMCS - 3030; 4800; 4808; 7610; 7620
Landfill Compactor:
826H (S/N: AWF1-UP)
836G (S/N: BRL1-UP; 7MZ1-UP)
836H (S/N: BXD1-UP)
Soil Compactor:
825H (S/N: AZW1-UP)
Wheel Dozer:
824H (S/N: ASX1-UP)
834G (S/N: BPC1-UP; 6GZ1-UP)
834H (S/N: BTX1-UP)
Wheel Loader:
980H (S/N: MHG1-UP; A8J1-UP; JMS1-UP)
988G (S/N: BNH1-UP; 2TW1-UP)
988H (S/N: BXY1-UP)

Description of Change: On the machines listed above, the transmission output signal can be adversely affected under certain circumstances. These conditions may result in complaints of harsh shifting, usually during directional shifts. New software is now available which can help prevent speed signal issues, therefore reducing shift harshness.
Adaptable To: The new software is adaptable to the machines listed below. Refer to Table 1 for the correct software part number.
Note: The software part number in the table or a newer version may be used. Table 1
Item Qty Part Number Part Name Description Adaptability
1 1 350-1293 SFWR GP-A5000 836H Power Train Flash File S/N:BXD1-UP
2 1 350-1294 SFWR GP-A5000 834H Power Train Flash File S/N:BTX1-UP
3 1 355-7177 SFWR GP-A5000 980H Power Train Flash File S/N:JMS1-UP
S/N:MHG1-UP
S/N:A8J1-UP
4 1 361-2929 SFWR GP-A5000 988H Power Train Flash File S/N:BXY1-3999
5 1 362-1273 SFWR GP-A5000 824H/825H/826H Power Train Flash File S/N:ASX1-UP
S/N:AZW1-UP
S/N:AWF1-UP
6 1 377-0704 SFWR GP-A5000 988H Power Train Flash File S/N:BXY4000-UP
7 1 383-2039 SFWR GP-A5000 988G Power Train Flash File S/N:2TW1-UP
8 1 383-2054 SFWR GP-A5000 988G Power Train Flash File S/N:BNH1-UP
9 1 383-8712 SFWR GP-A5000 836G Power Train Flash File S/N:7MZ1-UP
10 1 383-8713 SFWR GP-A5000 836G Power Train Flash File S/N:BRL1-UP
11 1 383-8714 SFWR GP-A5000 834G Power Train Flash File S/N:6GZ1-UP
12 1 383-8715 SFWR GP-A5000 834G Power Train Flash File S/N:BPC1-UP
Mark

Good info. Mark, this was exactly our problem, one all three of our machines.

Mark, Is there a Number or something to identify the Service Memo that the information on the 988H springs is in? Years ago I used to get the monthly Service Magazines that that kind of stuff would be in but that stopped several years before I retired.

I would like to see if I could get this information to pass on to the boss at the quarry as they have a few like the 988H and possibly some of the 980G's that might be in this group.

Or if you could send me the complete service letter on this that might help too. I could send you an email address to send it to in that case.

hi Ken, try these numbers in media search SEPD 1516 and SEPD 1339
from memory the PIP was an after failure repair only. not all machines failed ,not sure why but as a precaution on a service we did an transmission software upgrade which usually improved the shift sequence anyway .the machines that had the software upgrade usually didn't give much trouble with in the warranty period.
if you cant access the articles send me your email an I will forward you a copy
Mark