Allison Transmission Questions

[peety1]

Re: Allison Transmission Questions

The tech that replaced the ecu last week said the clutches are indestuctable...I don't want to run out of clutch facing 3 months after the warranty is out....It has never thrown a code...just slips major in 3 to 4 shift.....

BTW: This in a motorcoach that weighs 31,000 lbs. pulling a gmc yukon xl at 5800 lbs. The coach is rated at 41,000 gross including 10,000 lbs tow rating at hitch.....


Thanks

 

[dbarton291]

Re: Allison Transmission Questions

The clutches are tough, but it is possible something was not right when the transmission was new. Perhaps a clutch clearance too wide, etc.

 

[peety1]

Re: Allison Transmission Questions

Thanks, Are the solidnoids internal or external ?

 

[dbarton291]

Re: Allison Transmission Questions

The shift solenoids are internal. You have to drop the control module (bottom of the trans where the filters are) to get to them. There's no oil pan like a car transmission has.

 

[peety1]

Re: Allison Transmission Questions

Thanks, I'll keep you posted as to the progress of diagnosis and repair.....

 

[peety1]

Re: Allison Transmission Questions

One more question, what should be the tranny oil temp when in transit level ground ambient 75 degrees...mine is running around 165-170 degrees ....however it is cold natured when idling...the touch pads show code 70 low temp....I have to power static heat the oil in drive until it will read....then it is around 125 degrees.....

thanks..

 

[dbarton291]

Re: Allison Transmission Questions

170 is fine. Cold natured at idle is fine - there's no work going on to heat the oil. Most run around the engine thermostat temp going down the road (oil/water cooler). At 300 to the cooler it's too hot. 250 in the sump max.

 

[peety1]

Re: Allison Transmission Questions

Thanks, I'm scheduled for early am looksee at allison/ocala...will advise what the deal is....

 

[AllisonMan]

RE: Allison Transmission Questions

what the problem is is your throttle position sensor is having issues or not returning. The Transmission ecu thinks you have more than 9% throttle because it is stuck and then it will not allow you to go into gear.
Thanks and have a great day!
The real Allisonman rfranzen@pac-power.com

 

[AllisonMan]

Re: Allison Transmission Questions

Petey,
Have they checked the C2 oil pressure? They used to have a tendancy to have cracked housings which would give you a 3-4 slip. If this is a 2006, it should have the updated housing in it but things do break. Have they run what is called a Transhealth check with their laptop? This will tell you if your clutches have to much clearance without tearing the trans apart. Has the oil dipstick been calibrated? When this started, did anything new happen to it like oil change or anything? Please contact me thru email at my work rfranzen@pac-power.com and I am sure I will be able to help. This other guy knows his stuff but he just missed some info. I am the one who originally started this thread and I have worked on Allisons for 29 years and am now an Allison element 1 representative.
Thanks and have a great day!
Allisonman
aka Rick Franzen
Pacific Power Products/Ridgefield, WA

 

[sitdog84]

RE: Allison Transmission Questions

Did you ever find out what the code d1-2112 was?? I have the same code on mine and I cant shift it into drive.

thanks
Ken

 

[C Nash]

Re: Allison Transmission Questions

Ken those were so old post so they might not still be around to answer your question. I did not go back to see if the person that asked was a regular here. Welcome to the forum and maybe someone can help

 

[jljeeper@msn.com]

RE: Allison Transmission Questions

BSmith

Did you ever get this 21-12 code resolved. I have the same exact problem and am looking for help. My Service light is also on. Trans won't shift until very high RPM.

Thanks

Jon

 

[lightfoot2]

AT 542 filters

Dear Allison Man,

I have a 94 Coachmen with the AT542. I'm about to change the fluid again and wonder if I should change the internal filter. The trans has about 60,000 miles and I doubt that the internal filter has ever been changed. The Dexron III fluid in it is clean. The trans functions well.

If the internal filter needs changing, can you suggest a source to buy in the Richmond, Va area? Also, can I reuse the pan gasket if it is in good shape? Does it make sense to use silicone backup if the gasket is not perfect? Is it ok to skip the cooler flush if I keep the same Dexron III fluid?

Thanks in advance for your help.

 

[jljeeper@msn.com]

RE: Allison Transmission Questions

Disregard. My tps cable cotter pin broke and the linkage came detached. All better now.
Thanks
Jon

21-12 all gone

 

[jljeeper@msn.com]

RE: Allison Transmission Questions

dbarton291 - 9/17/2006 8:28 PM

Once the ECU comes back from DMR, if that doesn't fix the cruise issue, maybe putting an output speed sensor in the trans might work. I once worked on a speedometer issue for a guy, and that one turned out to be the terminals at the interface. Someone had probed them and distorted one of the female terminals so it wasn't making a good, tight connection. You had to look really close to see it. We tried everything, we thought. Once we replaced that terminal, the speedo worked fine. Just another suggestion for future reference. Let us know what the fix is. This has got me extremely curious.

I finally went out and bought the King Cruise Control. Problem solved. Well sort of, when I first installed the King Control it didn't work either. It didn't work for the same reason that my factory cruise didnt work. A bad speed signal. At least my previous troubleshooting was correct. The support guy at King Controls told me to run a new wire from the Allison ECU back to the King Control (Circuit #157 Purple wire). That was it, all better now. I suppose I could have fixed my factory cruise the same way. I'll never know. $600 cruise control. at least it did interface with my factory controls on the steering wheel. The most important thing is I now have Cruise that works very nice.

Thanks for your support

Jon

 

[dbarton291]

RE: AT 542 filters

lightfoot2 - 2/10/2008 7:03 PM

Dear Allison Man,

I have a 94 Coachmen with the AT542. I'm about to change the fluid again and wonder if I should change the internal filter. The trans has about 60,000 miles and I doubt that the internal filter has ever been changed. The Dexron III fluid in it is clean. The trans functions well.

If the internal filter needs changing, can you suggest a source to buy in the Richmond, Va area? Also, can I reuse the pan gasket if it is in good shape? Does it make sense to use silicone backup if the gasket is not perfect? Is it ok to skip the cooler flush if I keep the same Dexron III fluid?

Thanks in advance for your help.

Go to www.allisontransmission.com Go to the service locator and you can find an authorized Allison outlet to sell you the parts. Do not reuse the pan gasket and definitely change the internal filter/screen. I would recommend TranSynd fluid. It's the best fluid Allison knows how to have made for a heavy duty automatic truck transmission.

It should not be necessary to flush the transmission cooler unless the transmmission has failed. If that happens, you also need to make sure a filter is placed in the transmission cooler line that runs from the cooler back to the transmission. The local Allison dealer should be able to help in that case.

Allison does not recommend the places that hook up fittings to the cooler circuit and pump fluid through the transmission that way. They recommend dropping the pan, and changing the fluid and filter that way.

 

[lightfoot2]

RE: AT 542 filters

Mr. Barton,

Thanks for the advice on the AT542. Are you filling in for the AllisonMan? Or are you the AllisonMan?

I was a bit surprised that you referred to the AT542 as a heavy duty truck transmission. I thought it was one of Allison's wimpier models.

Since I wasn't planning on flushing the cooler and torque converter, I thought mixing the Transynd (sp?) with Dexron III might not be advisable.

Thanks again.

 

[jljeeper@msn.com]

RE: AT 542 filters

You will find that Allison does allow mixing of Dexron and Tranysnd. Allison says that after the second change of Transynd it is considered 100% Transynd and qualifies for the extended change interval and or extended warranty may also apply. Not after the first change since a large quantity of Dexron would be still in the converter. 5 years/100,000 mi I believe is the extended interval. Use Google

 

[dbarton291]

RE: AT 542 filters

lightfoot2 - 2/12/2008 6:37 PM

Mr. Barton,

Thanks for the advice on the AT542. Are you filling in for the AllisonMan? Or are you the AllisonMan?

I was a bit surprised that you referred to the AT542 as a heavy duty truck transmission. I thought it was one of Allison's wimpier models.

Since I wasn't planning on flushing the cooler and torque converter, I thought mixing the Transynd (sp?) with Dexron III might not be advisable.

Thanks again.

The Allison Man is one of the knowledgeable folks at one of their distributors out west. I am not AllisonMan. I couldn't fill the role as AllisonMan. I don't look good in a cape and tights............... (superman humor for those of us that remember). I just pop in as time allows.

Mixing Dexron and Transynd is okay as described by jeeper. That's one of Transynd's more endearing characteristics. It plays well with others.

Heavy Duty Truck Transmission: Here's what I mean. An Allison automatic is spec'd into a vehicle that does work. Most vehicle that have an Allison are vehicles spec'd to do a specific task, like a bus or a delivery truck, or a used food vehicle (garbage packer). These vehicles use about the same horsepower (higher torque usually) as a car to operate at a much higher weight in a limited speed range. That is very different that a car transmission that is used in a vehicle with a high power to weight ratio, and therefore has power to spare. In the vehicle that works, the transmission has a much bigger job to do, as does therefore the fluid. Dexron is basically a fluid for automotive automatics. There's nothing wrong with it, but Allison has learned over time some of the characteristics for transmission fluid that are desirable in a vehicle that has a much different duty cycle than a car.

Take even an AT-542 or a 1000 series apart, and lay them next to a 4L60, and the differences become obvious. Pinion gear size, pump capacity, size of the clutch plates, etc. are orders of magnitude larger in an Allison.