Allison Transmission Operating Temperature

[ronandsue74]

I have a 2005 Country Coach 36' with the Cat C-9 400 HP engine and the Allison transmission: Model HD3000MH, S/N 6510488801 04C24.

I have changed the filters to the new high capacity filters and changed the fluid to the TES-95 fluid.

My transmission temperature runs at about 220 degrees. The temp sending unit is located on the left outlet hose coming out

of the transmission.

Is this operating temperature OK? or should I be concerned?

Thank you,

Ron Jacobs

CC #51264

[wolfe10]

Ron,

Couple of questions:

Have you checked the fluid level using the shift pad?: http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA3360EN.pdf

Was this the same temperature you saw under the same conditions before the fluid/filter change?

And assume you used Transynd (TES-295). Should have been about 19 quarts to change it.

Brett

[ronandsue74]

Brett,

Yes I have checked the transmission fluid level using the shift pad. I got a reading of oLoK. My dipstick also says my fluid level is full.

Yes the temperatures have not changed since I changed the filters and fluid.

Sorry for the error, yes I used Transynd TES-295.

Thanks,

RJ

[vtbigdog]

This should answer your question...

http://www.digi-panel.com/trannyoil.htm

[wolfe10]

RJ,

It is difficult to compare transmission temperatures with the Allison transmission between different coach makers, as there is no "proper" location for the sender unit. Some chassis/coach makers mount them in the transmission, some in the line out of the transmission to the cooler and some in the return line from the cooler. Different readings at each. If this reading is in the line out to the transmission cooler, that is fine.

Because the torque converter in your Allison locks up at higher RPM's in 2nd", and is locked in 3rd, 4th, 5th and 6th gear there is not a lot of heat buildup due to the converter slippage except in very slow stop and start driving. The transmission will generate more heat is when stopped for a long period with the transmission in Drive. Easy solution if you are stopped and transmission temperature starts climbing is to put it in Neutral until you are ready to move again.

The other cause of added heat load is, as it is on any transmission, HUNTING. Hunting between gears is caused by a grade that is not so steep that it stays in the lower gear, but too steep to remain in the next higher gear. So the transmission shifts-- for example 5-4-5-4-5-4. This builds heat in any transmission. Easy solution on any transmission is to dowhshift so that the transmission stays in the lower gear until the grade eases and you can return to a higher gear. With your Allison, use the "down arrow" to select the lower gear when this occurs. After the grade eases, hit "D" or use the "up arrow".

Brett

[desmo]

Ron, for what its worth my Beaver owners manual for the Allison MH4000 says shut down if temperature is over 275 degrees F. It normally runs around 200 to 220. As Brett says it depends where the sending unit is located, on mine its right next to the transmission output cooling line. Also if I'm in stop and go traffic the temperature will climb to 220.

[ronandsue74]

Brett,

My temperature sending unit is located in the line going out to the cooler. So I guess my temperature running at 220 is fine.

My transmission cooler is intergraded into my engine radiator. If it were to develop a leak I would have a real (expensive) mess on my hands. For this reason, would you recommend I install an exterior stack transmission cooler. If you do, can you give me recommendations as to where I can buy the right cooler. I live in the Dallas area.

Thanks again,

RJ

[ronandsue74]

Thanks, my setup is like yours, so I guess my temps are ok.

RJ

[richbinkley]

Ron

I worked on Allison products in my career for a truck manufacturer. 1st in my opinion your 215 degree for converter out is OK, especially if this is the max you see going up grades or in high ambient etc.

I do not have direct experience with Motorhomes with Allison ( I have a Ford F53 ) so this is just a guide based on my truck knowledge.

There are two concerns the with the oil temp, one is the oil temp in the the sump which Allison says should be max 250 degree so the shift solenoids do not overheat . 2 - the life of the oil as jtbigdog discussed. High temp decreases oil life and requires more frequent oil changes.

Allison install data says max converter out should be 300 degree F

Also, Allison data says the sump temp.( which can be seen from a service tool) should be 200 degree F typical and max 250 degree F.

To me your 215 degree converter out should provide approximately the typical 200 degree sump desired.

Enjoy the CC Motorhome.

again just a little additional info which I hope helps.

rich

[wolfe10]

Brett,

My transmission cooler is integrated into my engine radiator. If it were to develop a leak I would have a real (expensive) mess on my hands. For this reason, would you recommend I install an exterior stack transmission cooler. If you do, can you give me recommendations as to where I can buy the right cooler. I live in the Dallas area.

Thanks again,

RJ

RJ,

A couple of manufacturers HAVE had issues with poorly designed or executed transmission coolers that allow coolant into the transmission. But, this is NOT a wide-spread problem. I would ask that question on your brand owner's technical website to see if this is an issue with your particular unit.

If it is, Hayden makes transmission coolers of all sized. Note, if it working properly and does not leak, the cooler in the radiator works VERY well. In cold weather, the heat from the engine helps get the transmission oil up to temperature, and in hot weather, cools it. A separate oil to air cooler does not warm up the fluid in cold conditions-- in fact, can "over-cool" it.

Brett

[thestick5]

I changed the fluid on my Allison 3000mh per the article in Motorhome magazine. When I drained the fluid all I got out of it was 8 qts.

Before I did the change i ran a level check and it read 4 qts low. So I put 12 qts back in. After the change I ran a level check and it said level OK. Then I went on a trip. The fluid temp only gets up to around 140 degrees now so I am unable to run a test as the temp has to stay above 140 or no test. The dip stick when cold has fluid all over it and hot the same. it also takes a longer time now to shift back to 6th gear after climbing a grade when straight and level.

Any help on this??

Thanks

[wolfe10]

Thestick5,

Welcome to the FMCA Forum.

Did you change the two filters? You should drain 17-19 quarts when draining the Allison 3000 and changing the two filters.

I am concerned by the "4 quarts low" issue. The transmission is basically a sealed system (transmission and cooler). Loosing a GALLON is significant.

What fluid did you go back with? If Transynd, it not unusual for it to run cooler than Dexron.

I would not drive until you resolve the oil level issue. If too much oil in it, you can aerate the fluid and cause all kinds of issues with the transmission. By the same token, you can do damage of run too low on fluid.

Brett