My '03 lb7 with hypertech on level 3 towing a 22 ft. travel trailer in 5th gear and on cruise at 2000 rpm. Pulling a slight incline it "pops", puff of smoke out tailpipe, and tach jumps to 3500 rpm, and "service engine light" comes on. We pull over, take off hypertech, go to GM dealer, they tech2 it and diagnois 5th gear slipage/torque converter problem. We disabled 5th gear on shift lever and carried on. Is this a "major transmission" repair I have in the making? Any suggestions, please.

it sounds like 5th gear is slipping and its going into limp mode. what code is it throwing?
do you have any mods done to your truck?

Rebuild with a suncoast and be done with it.

Cant tow in 5th.If that was the first time it limped..Your fine,just dont tow in 5th again.Its a overdrive gear. I would do a trans service,and replace with transynd...I did in my 03 the first time I limped it,it held more power/and longer,when I limped it the 2nd time.

Don't tow with the hypertech on level III. As you have already discovered it's to much power for a stock trans with a load behind the truck. Find a reputable transmission shop and upgrade your trans. It will save you headaches down the road.

Later,
Stephen

Cant tow in 5th.If that was the first time it limped..Your fine,just dont tow in 5th again.Its a overdrive gear. I would do a trans service,and replace with transynd...I did in my 03 the first time I limped it,it held more power/and longer,when I limped it the 2nd time.

If the truck wasn't designed to tow in 5th gear then tow hual mode would disable 5th gear all together. I tow in 5th and 6th gear all the time, even before I had the built trans and never had a problem.


To the OP:
Towing in 5th with a stock trans and a tuner is a whole different story. Sounds like you slipped 5th going up a grade and limped the trans. Lower the power level and go about your business until you have the money for a built trans.

it sounds like 5th gear is slipping and its going into limp mode. what code is it throwing?
do you have any mods done to your truck?


Thanks for your help. I was so thankful that I could drive away that I didn't even ask for the code, just had them clear the check engine light. I'm not "gifted". :o:

Turn the power way down when you tow and you will probably be fine. You more than likely overpowered C2's. They will slip easier next time.

If the truck wasn't designed to tow in 5th gear then tow hual mode would disable 5th gear all together. I tow in 5th and 6th gear all the time, even before I had the built trans and never had a problem.


To the OP:
Towing in 5th with a stock trans and a tuner is a whole different story. Sounds like you slipped 5th going up a grade and limped the trans. Lower the power level and go about your business until you have the money for a built trans.

Your right!!! I forgot,its like 6000 ibs or somewhere close to that.Thanks for the correction.

well heres my problem...i started my truck and backed out of the driveway, when i put it into drive it sat there for a second then it lurched into gear. Its been doing it a lot lately and NO the truck was not cold. I had drove it an hour earlier. Then as i was driving, going about 35-40 (which is where it usually shifts into 4th gear), it then shifted up into 4th then down to 3rd then back up to 4th and down to 3rd again in a matter of 3-4 seconds. Ive noticed it slipping a little bit and my predator is only on the 65. Does anyone have a clue what my transmission is doing?

Its saying I'm toast.

yeah thats what i was afraid of.........which sucks because i dnt have any money for a tranny. its never limped though, thats why i didnt think it was done fore yet and im just thinking a clutch or something