Allison Transmission Questions


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Gerel Thompson

New Member
I have a 2002 National RV Tradewinds Model 390 with Cat 330 engine and the GM Allison 3060 transmission. I just had the first tranny oil and filter change done at about 10,000 miles...after the oil change, the tranny downshifted really hard going from 5th to 4th. Have driven it for about 100 miles since then on a test drive and still shifting hard only at that particular downshift...doesn't matter whether I am in "economy" mode or not...same downshift. Dealer in FL where I had service work done, changed the oil and filters a second time and used DEXRON III oil from the quart containers instead of from a bulk container. It seems to be a little better but not as smooth as originally.

I also experience really harsh downshift when I use the exhaust brake and I believe from all I can tell it downshifts into 4th or 3rd gear when using the exhaust brake.

Any thoughts or comments would be appreciated. I am heading for near Inpls, IN in about 3 wks and am wondering if I should find a GM Allison service shop there to have them take a look or not.

Thanks in advance for any info you might be able to offer to me.
 
A

AllisonMan

New Member
Allison Transmission Questions

quote:Originally posted by IU Fan

I have a 2002 National RV Tradewinds Model 390 with Cat 330 engine and the GM Allison 3060 transmission. I just had the first tranny oil and filter change done at about 10,000 miles...after the oil change, the tranny downshifted really hard going from 5th to 4th. Have driven it for about 100 miles since then on a test drive and still shifting hard only at that particular downshift...doesn't matter whether I am in "economy" mode or not...same downshift. Dealer in FL where I had service work done, changed the oil and filters a second time and used DEXRON III oil from the quart containers instead of from a bulk container. It seems to be a little better but not as smooth as originally.

I also experience really harsh downshift when I use the exhaust brake and I believe from all I can tell it downshifts into 4th or 3rd gear when using the exhaust brake.

Any thoughts or comments would be appreciated. I am heading for near Inpls, IN in about 3 wks and am wondering if I should find a GM Allison service shop there to have them take a look or not.

Thanks in advance for any info you might be able to offer to me.
 
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AllisonMan

New Member
Allison Transmission Questions

Hello IU Fan,
This is a tough one. Did the dealer use Allison filters? Is the dipstick calibrated correctly? My #1 question is, are there any codes in your ECU (computer)? Do you know how to check for codes? With the key turned to ignition, press the up and down arrows at the same time. If you press and the display reads O - L this is how you can check oil level and press the two arrows again at the samr time. You are in the code area if the display flashes a D then 1 then 4 more numbers if there is a code present, or D then 1 followed by a - means there are no codes. Are you confused? I hope I explained this clearly.If you have no codes and the distributer does what is called a fast adapt on your ECU without results, then it is possible that the ECU may be bad or need an update on the software level. I know that Allison dealers rates are cheaper, but by going to a distributer, you get the highest qualified Allison mechanics at this level. Your coach is under warranty so everything, if Allison related, will be covered.
Finding out what your preselect for downshifts on your exhaust brakes is easy. When you use them next time, look at your display. It will display another number besides 6th and that number is what you are programed for. If it is lower than 4th, have it changed to 4th. Also how do your batteries look? Is there any corrosion on the posts? This can cause odd problems with your Allison.
Too bad you were not coming to the NW (Portland area) because I am sure we could make you happy and your coach run smooth. If you ever get up here, stop on by the area distributer ( I do not want to say name and get booted for advertising)just to say hi.
Thanks for the tough question and let me know how things turn out. :)
 
G

Gerel Thompson

New Member
Allison Transmission Questions

AllisonMan-
Thanks for getting back to me with such great information. Yes, I did verify that the service dealer did install Allison filters during both oil changes....albeit, different numbers but they looked almost exactly the same and fit just fine...they said the difference in the numbers was due to it being a GM Allison replacement filter with a different manufacturing date.

I don't know how to detect whether or not the dipstick is corrected calibrated...perhaps you can elaborate on that for me.

I checked the ECU codes and of course when the O L came up it told me that the oil was too cold to measure...so, I will do that this coming Sunday after we've had a chance to drive it for awhile and get the tranny oil warmed up. The next press of the up and down arrows resulted in no ECU error codes.

Someone in the RV park where we are staying suggested unhooking the electrical wiring to the ECU on the tranny so as to reset the computer and let it learn all over again the shift habits. Does that sound like a good idea or not....even if it is a good idea, I'm not sure where to find those connections on the tranny.

Again, any help you might be able to provide will be greatly appreciated. Thanks...

IU Fan
2002 Tradewinds
330 Cat...Spartan chassis
 
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AllisonMan

New Member
Allison Transmission Questions

Hello again IU Fan,
Do not disconnect the ECU. This will not reset to fast adapt. You have a 2002 coach under full Allison warranty. I suggest taking to an Allison Distributer, not a dealer. They can set to fast adapt but my rule of thumb is you are only temp. fixing the problem, it will adapt back to the rough shifts, something is causing it. Let me know what area you would like to find a distributer and I will look up in my Allison location book to find you the most qualified distrib. The numbers have changed and if the dealer is using the new ones, he should have been able to say that they are now "Gold Series" written on top of them. When you go in they can check the dipstick calibration also. That would not be covered nor would any harness problem. Harnesses are OEM responsibility. Talk to you later. :)
 
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AllisonMan

New Member
Allison Transmission Questions

Hi again,
One thing I did not mention is the output speed sensor tonewheel. Have them check that too, but if everything was ok before the oil change and now it isn't, I would think it has to do with oil level or the filters. Have a great day! :)
 
G

Gerel Thompson

New Member
Allison Transmission Questions

Thanks Allison Man!! Our next long stop will be in the Indianapolis, IN area. So, anything in or around Indy would work, also, Terre Haute, IN would work as would Lafayette or Columbus, IN.

I will not do anything other than drive it to the Indy area as I normally would and will check the oil level using the shift up and down arrows to make sure that it reads ok.

Thanks again for your assistance....hopefully we can get into a really well qualified service area soon and get all of this figured out.
IU Fan
 
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AllisonMan

New Member
Allison Transmission Questions

Hi IU Fan,
I will look tomorrow in my distributer book for the best shop at the locations you requested. You are going to a good area since Allison is based in Indianapolis. Check tomorrow I should be able to get you an answer since I do this at night from my home, I do not have the book here with me. Have a Great Day!
 
G

Gerel Thompson

New Member
Allison Transmission Questions

AllisonMan-
I am hopeful you will find a really good distributor in the central Indiana area for me to go to. I luckily did have the service shop save the tranny filters for me...the old ones were number 29509723C with a date code of 05/01 and the ones they put in were number 29538232C Gold Series with a date code of 10/02.
I don't know whether that is meaningful to you or not, but thought since I had the info, I'd pass it to you.

Thanks again for your help!
 
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AllisonMan

New Member
Allison Transmission Questions

Hello IU Fan,
I was able to come up with a distributer in Indianapolis. It is Clark Detroit Diesel Allison. They are at 1340 Terminal Road, Indianapolis-IN,
(317) 783-6651. Our filters do say Gold series so They must have been genuine Allison filters. I hope Clark will be able to solve any issue you have with your Allison transmission. Have a GREAT trip!
:) :) :) :) :laugh:
 
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Gerel Thompson

New Member
Allison Transmission Questions

Thanks very much for all of the helpful info and I will be making an appnt with Clark DDA soon...and let you know how things eventually turn out.
 
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rbraucht

New Member
Allison Transmission Questions

Hello allison man,
I have a 1992 motorhome with 140,000 miles. It has the MD 3060 transmission. It always had a somewhat hard downshift from 5th to 4th but was liveable. I installed the exhaust brake myself about eight years ago and just have a toggle switch to control it as the micro switch on the throttle was way hard to set.( I live in Alaska and 40 feet of throttle cable in cold weather didn't let the micro switch activate much of the time unless I hooked up a spring that I couldn"t hardly push ). Anyway, now I am getting a severly harsh downshift in all gears weather I have the exhaust brake on or not. Also if I am dropping down a hill in 3rd gear and turn off the exhaust brake and select D on the shifter,the upshifts are somewhat harsh under compression. Any suggestions? Thanks
 
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rbraucht

New Member
Allison Transmission Questions

Allison man,Idid the code check and I get a D then 1 followed by a 2 and 1 then a 1 and 2 . Wassat mean? Thanks
 
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Phillip

New Member
Allison Transmission Questions

Hi AllisonMan,

I am purchasing a new DSDP and need to know where you are located. I will need someome to do my Allison work. I am located in Portland, Oregon. My E-mail adderss is prs5545@yahoo.com.

Thanks!

Phillip
 
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AllisonMan

New Member
Allison Transmission Questions

Hi there rbraucht,
Have you checked for codes using your tower? Press both arrows at the same time with the ignition on and then let go. You will either have an OL70 orD1 and either -- which is good bur I suspect you will have a D1 21 12 which would tell me you have either a worn throttle position linkage or even it may have come disconnected (granted you have a mechanical engine and not an electronic engine). Look at your engine throttle arm. See if there is a disconnected cable laying beside it (it will have a black rubber boot on it), if so connect it. I see just cotter pins falling out. You may also have a worn pin which when you let off the throttle, the electronic counts go below set parameters which log code 21 12 and fault the transmission ECU (computer) to like you were still stepping on the throttle at 100%, which raises the shifts and cause harsh downshifts.
If you do not have a code 21 12 , it is possible that your output spped sensor tonewheel is loose or even sheared the pin and is rotating.
I hope one of these solutions cures your problem. Thank you for the question and have a great day! :)
 
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AllisonMan

New Member
Allison Transmission Questions

Hi again rbraught,
I answer these in order and didn't even check your next question. It looks like you do have code 21 12 and check to make sure you hooked up the booted TPS cable i described in last response. Have a great day! :)
 
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AllisonMan

New Member
Allison Transmission Questions

Hi there Phillip,
We would be happy to service your Allison and even your engine and chassis if you would like to have to take to one shop instead of 2 or 3. We are Pacific Detroit Diesel Allison located North of Portland 14 miles past the bridge in Ridgefield, WA. Our address is 600 south 56th Place. Take exit 14 - Ridgefield, take a left and go over the freeway. You will see a Chevron station on your left and the next street past it is 56th Place. Make a left and go to the end of the block> You can't miss us. Please give us a call @ 360 887-7400 and ask for the Allison department. Thanks and have a great day! :)
 
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