CAT D6H TRANSMISSION

[Haybale57]

First time on this forum. Caterpillar D6H S/N #6FC00600
Issue started transmission running hot and slow to cool down. Cleaned everything
At some point got the plugged trans filter alarm came on.
Changed trans filter and the trans fluid #8T9572. Fuid looked clean the magnet had very little on it.
Didn't solve my issue
Ordered #3E-9350 & #391-7125 temperature and pressure switches along with service man.
Checked pressures. Pump and speed clutch 475 ,direction clutch 450
Also recently changed the priority valve due to shifting issues.
The trans filter alarm still come on after it get warmed up. I noticed the goes away when I idle down the engine. Serviceman isn't sure ob the next move. I assume the transmission will still run hot and takes a long time to cool down. Any would appreciate any help

 

[Nige]

Issue started transmission running hot and slow to cool down. Cleaned everything

Can you define "cleaned everything" in a little more detail please.
Kudos for posting a Serial Number BTW.

 

[Haybale57]

Thanks for the reply. Cleaned the Radiator. Filter. Screens I have not looked at the transmission cooler. Please address the second issue with the ( transmission dirty filter alarm ) . Recap the alarm come up after it warms up. But if I idle down it goes away?
I'm new to this forum how do I see all the replies?

 

[pittsburgh cat man]

What filter did you use? Std or high efficiency

 

[Nige]

I'm new to this forum how do I see all the replies?

Every reply posted in regard to your questions will appear below the last post in the sequence. Don't worry you won't miss anything if you check back here.

Please address the second issue with the ( transmission dirty filter alarm ) . Recap the alarm come up after it warms up. But if I idle down it goes away?

See the attachment. Can you confirm what Part Number of filter element (343-4465 I hope) is installed please.
It is possible that the 164-7577 filter bypass Switch has become tired and may need to be replaced.
Also check the spring #11. It should have a free length of 1.86 inches and an outside diameter of 0.50" which should produce a bypass pressure setting of 38psi.

NOTE: The parts listing I attached is NOT 100% correct. The use of filter element 132-8876 in transmissions has been discontinued and it was replaced by 343-4465. See the Service Magazine article SEPD1230 (Jan 2011).

I have not looked at the transmission cooler.

I would say you should seriously consider doing the following work on the cooling system:-

1. Remove and inspect/clean both sides (oil & coolant) the transmission oil cooler.
2. Remove and inspect/clean the engine oil cooler. (The coolant flows through this one before reaching the transmission cooler.)
3. Remove, disassemble, and clean the radiator both internally and externally.
4. Fit a new water temperature regulator (thermostat).

If you have an infra-red temp gun some numbers for in/out coolant temperatures of the radiator and coolers (engine & trans) might be useful. Also in/out oil temps as well.

 

[Nige]

I forgot to mention above that it IMO is perfectly possible the machine has two distinctly separate problems that are only related to one another in as much as they both involve components in the powertrain oil system.

 

[Haybale57]

I installed #132-8876 filter. Filter 343-4465 was not offered. I installed switch #391-7124 that should be the replacement for #164-7477. The # 11 spring p/n 9m-1986 comes up as a good part. Not sure where it is located. Is it on the filter can ?

As far as removing and cleaning the coolers. I'm planning on that. Other then the main radiator and hydraulic cooler,the only other cooler I know of is mounted on the left side of the engine. I plan on taking it off to check and clean it

 

[Nige]

I installed #132-8876 filter. Filter 343-4465 was not offered. I installed switch #391-7124 that should be the replacement for #164-7477.

I suggest that you go back to your Cat dealer armed with a printed copy of SEPD1230 that I attached above and get hold of a 343-4465 filter element. The issue is that 132-8876 is still used in other applications so it is not cancelled. That plus the fact it is still (incorrectly) listed as being the correct transmission filter is why they sold it to you. A smarter parts counter person would have known better. The fact is that the recommendations of SEPD1230 trump the Parts Manual for your machine.

The # 11 spring p/n 9m-1986 comes up as a good part. Not sure where it is located. Is it on the filter can ?

The spring and bypass spool are on the filter housing. See the attachment I uploaded above. They should be right behind the switch because it’s the spool moving that operates the switch and puts the plugged filter warning light on.

 

[Haybale57]

I don't see the mechanism on the filter housing ?

Also looked at the transmission cooler. I know I'll have to drain the antifreeze but do I have to drain the transmission fluid to get the cooler out.

 

[Nige]

Also looked at the transmission cooler. I know I'll have to drain the antifreeze but do I have to drain the transmission fluid to get the cooler out.

You do, and while you are at it don't forget the engine oil cooler.
Procedures for both are attached.

I don't see the mechanism on the filter housing ?

Can you post a photo showing the location of the 391-7125 Switch that you replaced please.

 

[Haybale57]

I'll get pictures tomorrow. Looking at the procedure on the D6H trans cooler. The cooler in the PDF is mounted vertical my cooler is much harder to get to and mounted horizontal

 

[Nige]

Looking at the procedure on the D6H trans cooler. The cooler in the PDF is mounted vertical my cooler is much harder to get to and mounted horizontal

There are two procedures in that pdf. The transmission cooler is the second one and IIRC it is mounted horizontally. Yes it is hard to get to.

 

[Queenslander]

We had exactly the same problems with a D7H soon after purchasing it.
The alarm issue was cured by changing the UHE filter with the advanced efficiency version as per SEPD1230 that Nige had provided.
After taking temp readings over a long period of time I convinced myself that the transmission heating problem was a cooler issue and ordered a new genuine part.
After pulling the old one we found it was aftermarket but reasonably new and appeared to be in very good condition.
We swapped it anyway and ,luckily, cured that problem as well.

 

[Haybale57]

Attached are promised pictures.
Location dirty transmission filter new switch

 

[Haybale57]

Transmission cooler location

 

[Nige]

Attached are promised pictures.
Location dirty transmission filter new switch

If you remove the plugged filter switch and look in the hole underneath it you should find a moveable spool (may need a magnet to remove) with a spring underneath it. Below a snip from the 9W-0935 attachment in Post #5. The switch in your photo is installed in place of Plug #13.

 

[Nige]

Transmission cooler location

The procedure for removing the D7H transmission oil cooler in the SENR3238 attachment I posted earlier should work. Sometimes the manuals assume a certain capability of the person reading it to read between the lines and use procedures as guidelines rather than take it literally. At least you can somewhat see that cooler. On a lot of tractors they are buried deep in the bowels of the frame completely hidden from view.

 

[tctractors]

The Trans cooler is not a bad job to remove with a small pull lift and a sling, but you also need to strip down the engine oil cooler above the oil filter as it will be pegged up most probably, the water flows from the water pump through the engine oil cooler then into half the transmission cooler, the water then turns at the end case and flows back up the other half of the cooler into the engine via the nasty gasket hole, get yourself comfortable sat on those track pads.

 

[dimi]

We had exactly the same problems with a D7H soon after purchasing it.
The alarm issue was cured by changing the UHE filter with the advanced efficiency version as per SEPD1230 that Nige had provided.
After taking temp readings over a long period of time I convinced myself that the transmission heating problem was a cooler issue and ordered a new genuine part.
After pulling the old one we found it was aftermarket but reasonably new and appeared to be in very good condition.
We swapped it anyway and ,luckily, cured that problem as well.

One question. At what pressure does the oil flow through the oil cooler? My tractor has a pressure gauge plug on one of the pipes, but there's no mention of it in the manual.

 

[Nige]

One question. At what pressure does the oil flow through the oil cooler? My tractor has a pressure gauge plug on one of the pipes, but there's no mention of it in the manual.

In my experience anywhere between 15-30psi with the oil at normal operating temperature and the engine at High Idle RPM. It is unusual to find specifications for this pressure in the service manual.