850 case dozer transmission help

[mile225]

My 850 case dozer transmission overheats after about 45 minutes of running. Then the left side track quits pulling when in high. What could possible causes be? Can the transmission be tore down with it still in the dozer or does it have to be removed? Any help would be greatly appreciated.

Torque converter reworked and charge pump replaced about 15 hours prior.
Thanks for any info.

 

[Dickjr.]

What model 850? To remove the transmission you undo the tracks , disconnect drive shafts hoses etc and the whole assembly comes down and out the back with the finals still attached. Those trans are pretty complicated. Generally they are rock solid. Sounds like a weak clutch pack bypassing allowing it to build heat then it finally gets hot enough to just bypass. I'm just over the hill from Gravel Switch. Friend of mine did a total rebuild on his 850H , grand total was 12K. Came with 6 month unlimited hour warranty. You can also cut the trans filter open and check for debri or even get it hot and pull an oil sample send it to Bale or Wilson's for analysis.

 

[alrman]

Welcome to the forum mile225!
Dickjr. is on the money.
They really need to come out to be repaired efficiently. Even though I have heard stories of guys doing them still fitted - crazy if you ask me.....:spaz
Sounds like you have a problem with a couple of clutch packs working at the same time, caused, maybe by worn oil control rings under the shaft end caps. If this situation exists, over a prolonged period, it will superheat the oil & cause the dragging clutch pack to burn/wear out, before it's time.
If your pressure gauges are still working you will often see the pressure drop off when the problem pack is engaged, accompanied by a time delay in selection.
Drain the oil & pull the suction screen - it will tell you the story. Post pictures of what you find, if you like.

 

[mile225]

Pulled the suction screen tonight and found it full of aluminum shavings. I guess ill be tearing into it soon. Thanks for the info.

 

[alrman]

That's some serious trash you have there! ...... Do you know when that screen was last cleaned/inspected?

 

[Garrie Denny]

That is a very expensive looking filter catch, regardless of when it last was changed, I hope the problem is not as bad, best of luck.

 

[mile225]

The screen was cleaned and fluid and filter changed when torque converter was repaired. I had to replace all the seals in the torque because it was just dumping fluid.

 

[alrman]

Seeing that much metal in a screen is not good - to think it was made in 15hrs of use - is even worse.......
I'm here to help if required

 

[Outasite]

The timing is a little suspicious,15 hrs after converter.I wonder if something in the converter went amuck!

 

[mile225]

I finally got the transmission out and tore down. I found that the reverse clutches were badly burnt, and I believe they were staying engaged and thus causing the heat. The cover on the rear of the trans that feeds fluid to the forward/reverse clutches was found to have fairly deep grooves from the sealing rings. I think this is the source of the bypassing fluid keeping the rev clutches partially engaged. Now my problem is that my case dealer is not able to get this part. Any suggestions?

 

[Outasite]

Have it bored out and press a sleeve in it.Be sure to drill the feed holes first,and lock tite,as well as press fit.

 

[mile225]

Have it bored out and press a sleeve in it.Be sure to drill the feed holes first,and lock tite,as well as press fit.

That's what I was thinking.

 

[Outasite]

Easy fix,and a LOT les money than a new one!

 

[markmc60]

could I get an update on your tranny/clutch issue

That's what I was thinking.

could I get an update on the tranny/clutch problem you had and how you finally resolved it.
we have an 850 that after a couple of hours it is slow to shift between high and low speeds.
trying to gather as much info as possible before we do a full backflip with a twist into the pool.

 

[alrman]

could I get an update on the tranny/clutch problem you had and how you finally resolved it.
we have an 850 that after a couple of hours it is slow to shift between high and low speeds.
trying to gather as much info as possible before we do a full backflip with a twist into the pool.

Are you also rlbz71? who has same problem from Texas?
Don't want to double up on my diagnostic assistance.....

 

[mile225]

could I get an update on the tranny/clutch problem you had and how you finally resolved it.
we have an 850 that after a couple of hours it is slow to shift between high and low speeds.
trying to gather as much info as possible before we do a full backflip with a twist into the pool.

My 850 had numerous problems. The pto shaft cover that directs fluid to the forward and reverse clutches had grooves worn in it from the oil control rings. After the oil warmed up, it would start bypassing, keeping both forward and reverse clutch packs partially engaged. I replaced all the clutches and seals in the transmission. I got the pto cover used.

The torque converter was the source of all the alluminum shavings that I found in the suction screen. The center carrier and the pump drive gear bushing were worn causing the turbine and the impeller to touch. I was able to get those parts aftermarket.

So far so good. Roughly 1000 hrs on it since the repairs. Just a couple weeks ago I resealed the final drives and put on new rails and sprockets.

 

[cblack4395]

Any updates? I started a post on the same issue not long ago. Just finished my pressure check. It's good for the first 15-20 min then it won't move and pressure drops to 150psi at 2000rpms and 100psi at idol. The driveshaft still spins.