I left for work and dropped my son off at daycare. I was leaving the subdivision and when I tried to accelerate, the truck acted like is was slipping badly. I stopped and tried reverse, which again barely moved. It threw the SES light. I had the wife come back and pull me back to the house.
Since I had put on a larger transmission cooler, I decided to restore it to factory before calling the tow truck. After putting the factory cooler back on, it worked just fine. The two codes were 700 - transmission control system malfunction and 747 control circuit step error. Of course, I sent my pred off yesterday to get it updated, so I had to go to Autozone to get them read.
The larger cooler was turned 90 degrees to the OEM due to having different fittings. I had to adapt to hosebarb and back to an AN -12 fitting. The in line was on the bottom and the out was on the top of the larger cooler. The overall height of the cooler was not any higher that the OEM cooler, so I would expect gravity to be a problem. Is th larger volume of the new cooler increasing the head enough to stop the pump of the Allison?
I have fittings being made so I can put the new cooler in the same orientation as the OEM, but they are not due for a couple more weeks. Is it coincedence that I changed back to the OEM and the transmission started working again? I don't think the hose or cooler are restricting the flow as both are bigger than the OEM cooler and lines. I also thought the cooler returned to the pan, so how would the pump be effected at all? Am I "vapor" locking they system? I do have the new NSBU switch. The engine and tranny had not come to operating temp yet. The other time it did a no go, the NSBU was replaced and all was well again. HELP!!
It's been running about 3 Weeks since the NSBU switch was changed and it was on a couple of days before that. Since the NSBU fixed it last time and the cooler was never off, I thought it was coincedence. It appears that might not be the case or I need to "prime" the cooler or something.
I thought limp left you a gear? I guess it was in 1st, so down one is nuetral? Edited by: chuntag95
I did ask Eric and he gave me the diagnostics for the code, which is a solenoid in the tranny. He said he didn't think my cooler had anything to do with it.
If the solenoid for 1st is sticking or weak, that might also explain why I get so hot when in stop n go traffic.
Chris, get me all the info you can on what they find. I have someone that would like to see it. Ask them to be as detailed as possible and maybe even get some snapshots of it, or if they can print out the freezeframe data from when it failed... you could email it to me?
Wouldn't you know it, as soon as I post I don't know nothing, they called.
The story is they are waiting on a tool from Kent Moore for the thransmission. They need the tool to do a TSB that they think is my problem.
Eric, have you heard about a TSB on transmissions not going or falling out of gear? I have asked for the TSB number and they said they would try to get it to me by tomorrow. Whatever the "problem" is, it is supposed to be ready by tomorrow.
I was told the mystery tool will not be in till next Tuesday. I guess it's made from unobtainium.
To top it off, they still didn't give me the TSB number like I asked. It sounds like the right rear bearing is going out on the S-10 I have for a loaner.
I am trying to be half full, but I think I'm going to be sick
Seems to me their blowing some smoke ... We dropped, entirely stripped a tranny (Allison) Minus pulling the rear (ball) bearing assembly without one special tool to empty cases,including dis assembly of the valve body ...Including NSBU to the driverside dip stick tube hole plug we don't use ... Whats left ??
I've pulled a TCM for OD lockout install no special tools either ....
If I had my Allison service manual here I could list all the special tools they say are needed .....Mostly needed for tear down ... Is your tranny out of the truck ??
The tool used for the tsb for drainback issue is just a rod with a u-shaped notch in it so that you can push in a valve and insert a pin to hold it in. A screwdriver will work the same way... As Mac said, no special tools needed for anything that they can do for a warrenty concern..
Mac, Did you guys take off the nut on the back of the trans that uses a spanner socket, looks like 4x4 socket for older chevy's? I had to modify a 4x4 socket to fit. Did you pull pistons out or just clutches? It sure would have been nice to have that L-shaped bracket that bolts to the pto cover area to hold that shaft in so it dont slip out of splines and make it not go togather, or didnt you have trouble with it? It took me another set of hands cause didnt have it or make something.
I tried searching the history for something similar, but couldn't locate anyone with the same issue . . .
I recently acquired a 2015 GMC Denali HD with about 85,000 miles on it. Since it had a gooseneck ball fitted, spent a majority of its life in the oil fields of West Texas, and no...
Quick question, I'm planning on doing the drain and fill one gallon at a time. How many gallons would be sufficient to do this process and have clean fluid in the trans.
Thanks!
Hey guys - first time posting here. I have an 09 LMM that i've had for about 4 years now. The truck has 225k miles on it. Mods are moonshine EFI live - exhaust - profab erg delete, basic stuff.
Problems started about 2 weeks ago, I drove to a friends house about 20 minutes away, all was...
Hello,
I recently serviced my Alison with the full service filter and fluid change and after driving it about 100 miles it started to shift hard from first to second. did it just a couple times, then stopped. Then after a week or so it became more often and then second to third as well...
Hello all, seeking advice regarding my 2002 LB7 with 300k. When the truck gets up to operating temperature, it seems to slip out of 4th and 5th gear when I push it much over 2000 RPM’s. Sometimes it doesn’t shift into 5th at all, and when it is cold it will cycle through all gears regularly. As...
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!
