Allision problem

[reel time fishing team]

Long time lurker but new member. Here is my question. I use my stock 2001 GMC Durmax to tow a 31 Contender, about 9,000# with trailer, gas etc. Never had any probelms in 65,000 miles until last weekend. Taking off from a light shifting from 2nd to 3rd the transmission, instead of upshifting acted like it wanted to downshift, engine immediately redlined and transmission went to neutral (even though shifter remained in D). After a few seconds the transmission went back into gear and the truck acted normal. Little while later, exact same thing. This time I took the tranny out of tow/hual mode and again it settled back into gear. Next stop light, happened again with a few new twists. First off the engine did not red line, the transmission just would not shift out of third gear and I got a "Service Engine Soon" light. Well I was in the country by this time with no place to pull over so I just kept going. Finally pull over and shut motor off. After I made a couple phone calls I decided to forge ahead to a dealer I know in Kinston NC. After the truck had been shut off, I still have the light on but now the truck and transmission work like nothing is wrong. I end up pulling the boat over 100 miles to the beach, drive back to Raleigh and have been driving around for a week with no problems (check engine light still on). I took the truck to a local GMC dealer but after they had it all day and could figure nothing out I got a very strong impression they can't even spell Duramax never mind know anything about one. The only comment after having the truck a day was, "bring it back, we think it is something electrical". I asked if they cleared the code and got the light turned off and they had not.

OK, am I right in thinking this thing has a code and that is causing the light? Is there anyone in the Raleigh area that knows anything about Duramax's and Allision tranny's? What is your take on what happened and the fact I have put something like 300 miles (including 100 towing) with out any more problems? Any help is appreciated.

Kirk

[Runaway]

Sounds like the NSBU switch on tranny may be acting up. Do a search for this switch and I think you may have to have it replaced. Others have had to do this with similar symptoms.

[Kennedy]

If you get to Charlotte, I've got 3 choices for knowledgeable service.

Could have seen a slip condition. Having the code(s) would be helpful, but then again I've also seen the TCM request MIL code set without a TCM coed set.

The other possibility stems from the air box used in 2001 trucks, it's "snorkeling" into the fender, and some programming updates. More details here:

http://www.kennedydiesel.com/dmaxairintake.html

[reel time fishing team]

Well here is an update. I have taken the truck to two different GMC dealers before I gave up on them. One at least could pull the code which related to excessive transmission fluid pressure. Personally I think that is caused by the truck's rpms hitting 3500 when the thing shifts wrong. He did also mention the internal filter had small amounts of metal. I guess that is normal? I know with outboard lower units you always get very small amounts of metal when you flush the fluid. He said not to be concerned about that.

The truck is now at an Allision shop here in Raleigh. I talked to the mechanic and he seemed to actually know what he was talking about, knew about the bad NSBU issues and even knew what limp mode was so I have some hope they will figure it out.

Kirk

[conejo]

I have had the same problem with my 2001. started just after i got it. The first time the deiler fixwd it for free. Said it was the transmishion saftey switch. This time the want $500.00 Bucks to fix it. Said again it was the saftey switch. Please let me know what tour guy has to say.

Thanks
Jake

[reel time fishing team]

Thanks for the feedback, it is back in the shop today. This things is a nightmare. I just want someone who can diagnois what the heck is wrong. I replaced the NSBU and it is still doing it. In fact, it now will do it without the boat hooked up. Everytime it is the second to third shifting point, drops to neutral and goes into limp. It still requires the rpms to be north of 2300-2400 to do it. The Allsion dealer I had it at last week was unable to complete their diagnostic work because they were told only GM can work on it (this came from higher up in Allision). I called GM customer service and they hooked me up with a third GM dealer. If they can't figure it out, I am trading it in on a Ford.

Conejo, was yours also only second to third that it happened? I'll let you know what this third dealer finds.

[reel time fishing team]

Dealer has pulled the code, it was 1721, anyone know what that means.

Kirk

[DmaxMaverick]

reel time fishing team

1721 is "no speed signal". Could be a number of things, either in the tranny/transfer case (sensor), or wiring (poor connection, bad connector/pin, dirty or corroded connection, parted wire, etc).

I'd suggest starting with the connectors. Ensure they are clean, undamaged and fully inserted.

Good luck

[reel time fishing team]

Thanks Dmax, that gives me some comfort they are headed in the right direction as they said they think it is something electrical. I should know more later this week.

Kirk

[reel time fishing team]

Well got the news today, they are replacing the valve body at a cost of $1700. I am not pleased :mad: :mad: . As much tlc as I have given this truck and tranny, no way should it need that kind of repair. The dealer claims that in their discussions with the tech people at GM, this problem has happened with other trucks too, not sure if it is year specific or not. All along I figure the Allision would be the last thing that had a problem given their reputation.

Kirk

[dmaxalliTech]

reeltimefishing....

Please Email me as soon as you see this. I have some people at Allison that want to get involved in your case. Not TAC consultants either.
tqauto@aol.com
or
emerchant@toddwenzelpontiacgmc.com
Eric

PS.. have the dealer hold off on there repairs until we talk..

[reel time fishing team]

Eric,

You have mail.

Kirk

[reel time fishing team]

Well we begin day 20 at the dealer, still no resolution on the problem but with some help from Allision personnel I believe we are getting close. Stay tuned as the full resolution of this problem will be posted.

Kirk

[Heartbeat Hauler]

I love mysteries and this is a real "What dunnit".
JP

[reel time fishing team]

OK here is the deal. We are still not certain of the exact cause of the demise of the tranny but we did snapshot the events twice yesterday and sent the data to Allision for analysis. The leading canidates were a sticking valve in the valve body or one of the clutchs going out. Here is the good news. The regional service mgr for GM has arranged for the entire tanny to be replaced. In addition, the power steering pump (which broke while they had the vehicle) is also being replaced. GM is footing the bill for the parts and I am footing the bill for the labor. I estimate the labor to be 10 hours give or take. I have to give a lot of credit to the Allision engineering folks for helping get this issue moving as prior to their involvement we were in the ditch. As things worked up the ladder at GM I was finally able to get what I consider a very fair resolution. The truck has 66k miles so the tranny is way out of warranty. I think GM recognized that the amount of time they had the truck in their possession was excessive (my words, not theirs) and that even though the tranny was out of warranty, it should not have this type of major problem. It is refreshing to see that if you handle the problem correctly that GM is willing resolve it in a fair manner.

Kirk

[ 03-19-2004, 09:00 AM: Message edited by: reel time fishing team ]

[Mudflap]

Exact same thing happened to me I shut down and sat for a while then went back to normal but the light stayed on. The dealer said the code they had was gobbldygook and to watch it. The SES light came on after that for no apparent reason, finally they replaced the ECM and the NBSU under warranty. The thing runs like a top and no further problems. I pull a 14,000lb fifth wheel. By the way the Allison warranty is three (3) years unlimited mileage, I have 78,000 miles on my truck.

[reel time fishing team]

Mudflap, you must have a different warranty than I do. Mine is 3 years or 36k on the tranny. Here it is on GM's web site.

http://www.duramaxdiesel.com/07_warranties/index.htm

Kirk

[2fast2]

The Allison transmission has NO warranty from Allison, according to the guys at the Allison shop in Charlotte. GM buys the transmissions without warranty and they supply their own warranty. This is why you can't get Allison transmission warranty work done at the Allison shop (unless you want to pay cash.)

Jim

[MAV]

Steve O in Mooresville, NC is the best Allison guy in the whole world. Works at the Allison dealer in Charlotte. He is the MAN!!!

[2fast2]

That must be true. The guys at the front counter there told me they have a tech who is THE EXPERT, and the way they said that was not to brag but to help. If I ever have a problem, I'll be there.
They also suggested changing to transynd, said you could FEEL an improvement.
It seems like they are proud of their transmissions and want you to be happy. Thats a good thing!

[DieselDavy]

Reel time fishing team,
Any updates? What did it end up costing you? Did they really stand behind the product or slip you the big one in one way or another?
Thanks,
Dave

[dmaxalliTech]

Hate to answer for him, but I think he got a complete trans. He only payed labor I think... My good buddy in Indy got involved and set it straight for him ;)

[reel time fishing team]

DieselDave, I ended up costing $1,000. I paid the labor and GM provided a new tranmission and a new power steering pump. I am very satisfied with this resolution. Just the ps pump alone was going to cost $600.

Eric, Thanks for all your help. The process was not going wll at all before your involvement.

Kirk

[GSXRTURBO1]

Eric comes through yet again!