Allison Transmission Questions

Discussion in 'General RVing' started by AllisonMan, Apr 5, 2003.

  1. jsparkes

    jsparkes New Member

    Allison Transmission Questions

    Hi Allisonman,

    Thank you very much for your concerted efforts in setting us all straight! I will give you a call to discuss the work in the shop and the info on the valve body.

    The other shop did not test drive the RV to make the diagnosis.
    He was very busy and gave me an educated guess as to what the possible problem may be. He also said that a test drive would be his first step. He also checked for any codes but found none.

    Thanks again for your help. :)

    Best Regards,

    jsparkes
     
  2. rt446dm

    rt446dm New Member

    Allison Transmission Questions

    Thank you Allison man for taking time to ancer.
     
  3. t savard

    t savard New Member

    Allison Transmission Questions

    Hi Allison Man,I have a 3060 transmission that when cold allows the engine RPMs to speed up between shifts. The outside temp needs to be abouut 55 degrees before this happens. After 4 to 5 miles the condition clears up. If pulling a hill the RPM limiter kicks in. I have a disiel pusher. It has done this since new, but now is gettig worse. All maint has been maintained. No error codes. No has been able to help. Hope you can.
    Is it correct that you have to change syn oil twice before you are allowed the extended oil change frequences (from dextron to syn)
    Thanks
    Travlintom
     
  4. TShrum1

    TShrum1 New Member

    Allison Transmission Questions

    Help Mr Allison Help,
    I have a Chevrolet 2002 Duramax with the Allison transmission, This is a C2500 four wheel drive extended cab pickup and up until now I have had no trouble with the Allison (in fact its a great transmission) The problem goes like this I now have about 102,000 miles, the truck has always been serviced by the dealer at the appropriate times including the transmission. While driving down the road somewhere around 62 mph all of a sudden the engine just revs up, as I release the throttle you can feel the transmission catch or take control again. This happened about six times on Monday and Tuesday morning while enroute to the Chevrolet dealer it was worse. Before I made it to the Dealer it would not shift into overdrive and as I came to a stop about a mile before the dealership, I heard like a loud breaking glass noise or grinding glass noise, as I pulled into the dealership the breaking glass noise was gone.
    The dealership called today Friday and said it was fixed, that a module had to be replaced. To replace it they had to pull the transmission back a bit from the engine to get to it, well thats what they said anyway, and explained to me the computer had put the engine/transmission into what they called limp mode (when it would not shift into overdrive) I picked up the truck and was told that the tail piece needed a seal that it had a very minute leak and they ordered the seal but I could go ahead and use the truck until next week when the part comes in, I offered to pay the bill and the service manager said Terry the part was only twelve dollars lets just wait until we finish putting in the seal, which I thanked him. Driving away from the dealership I had thought this was a very serious problem, I was so relieved it was not.
    Well after driving about ten to fifteen miles it started again around 62 mph it just like slips out of gear and the RPMS go way up and you hear the roar of the engine I let up on the accelerator it like takes hold and works ok for maybe four or five miles and then again the same thing.
    I really want to get this fixed but I don't know where to take it, I am sacred to go to like a transmission rebuild shop and I really don't think the dealership techs are all that great either. When I arrived at the dealership we checked the fluid and it was clear with a red tint and had no burn smell whatsoever so I need someone with words of wisdom. Thank you in advace for your help. Just for your information, I tow with this truck seldom and when I do it is a light small trailer. I do not know anything else to add to this with the exception that yesterday when I went by to get some tools out of the truck they had I think two hydraulic hoses hooked to the transmission but where they went to I have no idea other that they were very long.

    Thanks again
    Terry Shrum
    Tulsa, Ok
     
  5. meekna

    meekna New Member

    Allison Transmission Questions

    AllisonMan - I scanned throught the listings but didn't see this problem; I have a 2001 2500HD 8.1L and Allison.

    First problem is when the vehicle comes to a rolling stop and the accelerated pressed to move forward again, the transmission has not decided which gear to select, subsequently a violent downshift and head snapping take-off! is this normal?

    Second - during warm ambient temps (about 85-90deg F) the transmission makes two groaning noises at 50MPH, I can count on it everytime.

    Any ideas?
    Thanks
    Nathan
     
  6. Lolarace

    Lolarace New Member

    Allison Transmission Questions

    Hi Allison Man -
    Glad you're back. I have a similar problem to Meekna. I have also have a 2001 GMC w/ 8.1 and Allison 5 speed. When trans temp is above 175, after coming to a stop, when I accelerate the trans does a "double thump". Its almost like it was locked up or in neutral then has to get into gear before it goes. There doesn't seem to be any real hesitation. It is less noticveable in Tow-Haul mode. The dealer has reprogramed the trans. It helped for about 2000 miles then came back. It has done this since nearly new - now has 22,000 on it. Dealer seems to think it is Just an Allison, they all do it. I don't mind if it is normal and won't cause any problem.
    Thanks again for your time.

    Larry
     
  7. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hello jsparks,
    First off how many hours did we charge you I'm curious. What I would do next is have a pressure gauge put in C5 port and main and go out and see if when this happens, does pressure drop (especially after warm?) Then if low pressures, I would next drop the VB module and clean up the VB because in that year, I have seen little poliching beads that look like little flat brg rollers, stuck in valve bore. I would also change the solenoids associated with C5. Please let me know the outcome because my guys are pretty sharp and I wonder why they could not duplicate the problem. Was I there and offer a test drive with you to see if you could duplicate it? I look forward to hearing from you. Call me if you would like. Thanks and have a great day! :)
     
  8. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hello busbot,
    Sorry for the delay in answering but I was just allowed back to forum and am playing catch up LOL. The first thing I would check in the govenor on the left side of the trans on the rear cover. There is a cover with 4 1/2" head bolts. Remove bolts and the govenor is behind the cover. a very little bit of oil will come out. Next, hold the govenor by the nylon gear and let it hang down. Next, pinch the weights togeter on the head of the govenor and see if the valve inside the govenor shaft moves up and down freely. You may have a sticking govenor which will not allow it to relax all the way and not let you get 1st gear which you need for reverse. If that is ok, install a 250 pd pressure gauge into the 1/8" pipe plug that is by the shift selector (there are 2 plugs. Use the one that is in the deeper crevice of the two)Check pressure cold then warm and see if the pressure drops down around 125 psi. If it does in reverse, I would remove the VB and clean it to see if any sticky valves or if the checkball if it has one, has dissapeared. There is also a screen in the rear cover. In newer models it is under a big plug on the back of the rear cover on the bottom. See if that is plugged.Let me know if any of these helped.Thanks and have a great day! :)
     
  9. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    JADA,
    There is a nuetral safety switch on the side of the transmission by the selector. There will be 2 wires coming of it. You can manually shift back to nuetral if you have a stone bennet shifter (toggle switch) or if you have a cable and its in nuetral, you prob have a bad switch. Have some one in bus with brakes set and foot on brake. take 2 wires coming from bus chassis and connect them on chassis side. If it is the NS switch, your bus should start. Thanks and have agreat day! :)
     
  10. meekna

    meekna New Member

    Allison Transmission Questions

    Hey Lolarace - thanks for the info, I fine with it as long as there is nothing wrong!
     
  11. Lolarace

    Lolarace New Member

    Allison Transmission Questions

    Hi Meekna

    Let's hear from AllisonMan. The dealer may be full of it. Good luck.

    Larry
     
  12. jsparkes

    jsparkes New Member

    Allison Transmission Questions

    Hi Allisonman,

    I really appreciate your diligence in resolving the problem.I will call you when we return from vacation. Yes, I was charged over $400 for 4 plus hours for the time that my RV was at your shop with nothing resolved except a ground wire re-attached.I believe Aaron was the techs name. You will probably have the info in your records around the end of July under J Sparkes, Dolphin 34D diesel pusher with Allison md3060 transmission. I originally was going to have the trans serviced and synthetic oil put in but we ran out of time. We had to leave plus the oil looked good and it had been serviced at 25,000 mi. so we didn't stay the additional day.

    Best Regards,
    J Sparkes
     
  13. cvrvr

    cvrvr New Member

    Allison Transmission Questions

    AllisonMan

    Thanks for all the great info on Allison. I have a W-20 with an Allison 1000. I would like to add a mechanical temperature gauge. Do you know of a fitting that can be installed in the cooler output line so that I can install the temp sender.

    I took your advice and had Transyd put in at about 6000 miles.

    Thanks again
    George
     
  14. TShrum1

    TShrum1 New Member

    Allison Transmission Questions

    Hey Allison Man,
    Just an update, I decided to take my truck to the allison people in Tulsa after reading about you and your co. They were so busy but yet Bill the service manager siad I know you need your truck let me at least have Jim hook up and see what codes are there.
    These guys were so nice and if I ever have a real transmission problem I will go back, what they found were codes that did not make much sense as the Dealer had said and Jim suggested we start with the, I'm not sure what he called it something like the PCM or park or neautral control as mine is the older style, anyway he changed it, found a burnt connector up inside and as Jim said if this is not the problem it would be soon.
    He offered to test drive it but I said if it works I will know and if it messes up I will come back so I paid my bill,left and after about five miles it messed up. Thinking these guys are too busy they even said if we do a tear down it will be like Wednesday, I called my Dealer and went back there and loaded him and the mechanic and went for a drive, well it did it many times and as soon as the mechanic heard the noise he said Terry thats a transfer case I know it is, well thats what it is the Allison is ok and now that I went to the Allison Dealer I have a new switch that was going to be a problem.
    I was really impressed the guys at United Engines and I am sure they would have found the problem if it would have done it and they could have heard it. I was impressed because they work on the big trucks and buses such as you do, but they treated me like I was driving a big truck and yet it was only a pickup, The service manager is Bill Temme and was super! I even bought the synthetic oil and more filters while I was there.
    Thanks for a great forum to post our problems.
    Terry
    2002 Duramax/Allison
     
  15. jacques

    jacques New Member

    Allison Transmission Questions

    I have a 2004 Chevy 1-Ton Crew Cab 4x4 w/Duramax diesel and Allison T1000. When I decelerate from highway speeds and reach 43 MPH, the transmission releases and coasts without any noticable engine braking. Is this normal? If not, what could be the problem?
     
  16. duramax4by4

    duramax4by4 New Member

    Allison Transmission Questions

    I have an 02 Chevy Duramax. Today I was driving and the transmission went dead. What I mean is, it just basically went into neutral but was still in "Drive". I tried to put it in 4x4 and no change. What I did notice is that when I put it in Park and let it sit for a minute then put it in drive, the backlight behind the D(for drive) starts flashing. Any idea what might be the problem. I have 82k on my truck and it has been on a regular maintenance schedule.

    Thanks!!
     
  17. Serious Hardware

    Serious Hardware New Member

    Allison Transmission Questions

    Allsion Man,

    Thank you for putting so much time into helping everyone on this forum! I have a MT643 that won't kick down. I have replaced the cable reel assembly and adjusted it to be full extended at wide open throttle. Still no kickdown. Do I need to have the tranny rebuilt to get the kickdown working?
     
  18. Lolarace

    Lolarace New Member

    Allison Transmission Questions

    Hey Meekna-

    I just got back from the dealer again. He said there is a new service bulletin that updates two solenoids. He's going to order them and install them when I get back from vacation. I'll post in about 3 weeks with the outcome.

    Larry
     
  19. KAT100

    KAT100 New Member

    Allison Transmission Questions

    AllisonMan,
    I have a 2004 Newmar with 2500 miles on the odo. It has a 8.1 Vortec engine with a 1000 series Allison tranny. The coach runs and performs fine. Recently I noticed on the ground a few drops of transmission fluid. After crawling under I saw that the fluid was coming from the back of the transmission pan gasket. The bolts were tightened but it still drips (just a few drops). Fluid level checks OK if not a little high.

    Question? Is the gasket bad and needs to be replaced or could the fluid be coming from some other place? I have looked the tranny over and can see no other source for the leak.
    Also is this gasket a stocked part or must it be oredered?....The nearest Allison dealer to me is over 60 miles away.

    Any suggestion would be helpful....

    KT
     
  20. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hello Norml,
    I suspect the problem is in the valve body module. The converter relief stop pin may be worn or broken and when this happens, the converter drains all the fluid back out and it takes a while to fill it back up. You will need to take in and have this checked. Let me know how it goes and have a great day! :)
     

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