Allison 6 Speed symptom

[Paul T]

When traveling up a long hill, (I80 out of salt lake) 10 miles at a 6% grade, I received a warning beep and a message on the cluster “transmission temp high” not exact message, but to this effect. I was towing a 4 door jeep wrangler and outside temp was close to 90. The pedal was to the floor and I was moving about 25mph. I pulled over after about 30 seconds, turned off the air and put the unit in park. I then noticed that engine temp was about 1 needle mark higher than usual. This came down to normal after about 15min. I did not see the same issue for the rest of the trip, but I did take it easier on long up hill climbs by stopping half way up and going a bit slower (15-20mph)

Has anyone else experianced this problem?

[sgtjoe]

That would be good ole Parley's. I run by tach pulling that hill, around 2000-2200 and have never had the tranny temp warning. Engine temp will climb a little but not enough to be concerned about. It is not a grade to be running your dash air on, use your generator and the coach a/c's. If you think it's fun pulling, you should see it coming down, love my Jake brake. I travel up and back several times a year as a few of our favoriate camp grounds are up that way.

[JCM]

Never pull over on a long hill and shut the engine off. You can blow your radiator. If you must pull over keep your revs up to 1000 - 1500 till you see a cool down.
From experience.

[angelman]

Do not use dash a/c when climbing a hill. Your engine and tranny will love you for it. I would also change the tranny fluid. You have cut the life of the fluid by overheating it. Use a synthetic fluid. ( If your not already)

[CJBROWN]

And change that ATF now.

We've discussed those nifty temp guage units that clamp on the cooler line - think about getting one of those if you're towing a lot. Unfortunately, workhorse didn't see fit to put a gauge in, just a warning if you go over temp. My duramax has a temp gauge.

I was just saying, did a ATF drain and fill last weekend. Fluid was not bright red so was good to get some new oil in there. Amsoil Torque-Drive is what I use, have two allisons. BTW, did the truck too and the fluid was a lot dirtier than the MH. It tows the boat a lot and it's chipped to about 650ft lbs of torque, so I'm sure that has something to do with it.

AT's are easy to overheat in a RV and the driver doesn't even realize it 'till the fluid is burnt and then the thing eats itself.

[DAN L]

Quote:

Originally Posted by CJBROWN And change that ATF now. We've discussed those nifty temp guage units that clamp on the cooler line - think about getting one of those if you're towing a lot. Unfortunately, workhorse didn't see fit to put a gauge in, just a warning if you go over temp. My duramax has a temp gauge. I was just saying, did a ATF drain and fill last weekend. Fluid was not bright red so was good to get some new oil in there. Amsoil Torque-Drive is what I use, have two allisons. BTW, did the truck too and the fluid was a lot dirtier than the MH. It tows the boat a lot and it's chipped to about 650ft lbs of torque, so I'm sure that has something to do with it. AT's are easy to overheat in a RV and the driver doesn't even realize it 'till the fluid is burnt and then the thing eats itself.

have you looked at the scan gauge 2 for allison temps?

[CJBROWN]

Quote:

Originally Posted by DAN L have you looked at the scan gauge 2 for allison temps?

Seems like a neat unit, but more data than I care about. For reading and resetting CEL would be worth having.

A trans temp gauge is about half the cost for someone that needs that data. Most of the rest of it is on the Actia display, just sayin'.

[Stevegd007]

Paul T, YES we have had the same problem, it was just like you described. When my 38T was new and I was driving it home for the first time, my transmission overheated and the light came on. I turned right around and went right back to La Mesa RV and checked into the service dept. Workhorse paid to have an oversized transmission cooler installed, (was told by the service tech that there was a problem wrong electric program for the transmission and they had no fix, i.e. no new eprom program for the Allison). So it is like a 2nd radiator sitting in front of the regular engine radiator, its not small either. An it works great. Never have had an overheat problem since then. So look into a transmission cooler.

[Fred and Bonnie]

Quote:

Originally Posted by sgtjoe That would be good ole Parley's. I run by tach pulling that hill, around 2000-2200 and have never had the tranny temp warning. Engine temp will climb a little but not enough to be concerned about. It is not a grade to be running your dash air on, use your generator and the coach a/c's. If you think it's fun pulling, you should see it coming down, love my Jake brake. I travel up and back several times a year as a few of our favoriate camp grounds are up that way.

Joe, please explain how you climb I-80 eastboud from SLC and keep the RPM that low, surely you are not running a 8.1L engine.

[DriVer]

Quote:

Originally Posted by CJBROWN And change that ATF now.

I don't believe that changing the fluid is absolutely necessary because all 6-Speed transmissions are filled with Transynd. Transynd can take a licking and still keep on ticking!

At the end of the day, I climbed I80 out of SLC in 2005 and to my recollection I was able to make better speed than 25 MPH. One has to remember to keep the energy level as high as possible when climbing and to make better forward speed and RPM so the air flows through the cool pack. Another thing to look at would be the fan clutch.

I didn't know that a larger tranny cooler was available.

JCM offered good advice ... do not shut down the engine after a hard pull and allow it to idle at 1500 to 2000 rpm for about 2 minutes. Idle down the engine afterward for another couple of minutes before shutdown.