Hey everyone. I have an lb7 and few times when accelerating up a grade I get a jerk/buck but not all the time. When I'm in tow mode with my 5er hooked to me and it downshifts I get major jerking and bucking as if I was shifting a manual and not doing it smooth. Can't figure out why and is this bad.
Shifting issues
- Thread starter Sticky
- Start date
Could be any number of things. Is the engine stock or tuned? Transmission stock or built? TCM tuned?
I experienced something like this on my first built transmission, and it turns out a couple of the springs for the trim solenoids had snapped, so the TCM couldn't reliably control shift pressures. This eventually led to repeated tie-ups that snapped a shaft inside the transmission.
Your case might be simpler. It could be as simple as dirty electrical connections. Remove the big round connector at the back of the transmission and ensure there is no fluid inside it. If there is, clean it out with contact cleaner, and see if it shifts better. You will eventually have to replace the internal harness to fix that leak, though.
I experienced something like this on my first built transmission, and it turns out a couple of the springs for the trim solenoids had snapped, so the TCM couldn't reliably control shift pressures. This eventually led to repeated tie-ups that snapped a shaft inside the transmission.
Your case might be simpler. It could be as simple as dirty electrical connections. Remove the big round connector at the back of the transmission and ensure there is no fluid inside it. If there is, clean it out with contact cleaner, and see if it shifts better. You will eventually have to replace the internal harness to fix that leak, though.
I thought that it might have played a part in it. I was running banks which.... so I have gone back to stock and removed it. Should be receiving efilive with Kory Willis tunes and we will see how bad or good it is then. Mike L this is a trans you did and I only have 12k miles on it. I feel you did good like all you jobs so Im just trying to find the secondary source doing this. Unless your want to dig into it again Mike.
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Unless we can duplicate this and get it to do it on a regular basis it will be difficult to find. Could be a dirty ground, slow wheel sensor among other things.
I was only inquiring if he had for that reason as he said it was built. I should have been more specific I guess but am at work
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That's the bad part. It most likely won't on city streets. It's really the worst in tow/haul mode with my trailer up grades. Never did it once towing or not until the trans was built. That's why I think it has something to do with the trans but with out it acting up for you I'm lost
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what year is your truck? have you ran the truck on the stock tune when it does this? how many shifting miles do you think you have put on the trans in "tow/haul" mode only? and im not talking how many highway miles, how many times you have made the truck make that bad shift since it was built. does it do this in normal mode as well?
2004. Yes in stock mode with everything disconnected. Almost ever time it downshifts to keep speed up on grades. Not as much on flat ground but does still do it. Yes it will in normal mode but not as extreme of a jerk
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Need a tech 2 to get soft codes and look at wheel speed sensors, and need to look at rail pressure too.
Mine did some odd shifts randomly (mainly at higher speeds) and it was a wheel bearing.
Mine did some odd shifts randomly (mainly at higher speeds) and it was a wheel bearing.
The experts here on this site right now, need your complete sig.They dont know if Mike L put the tranny in,what torque converter,what cp3 ,has the truck been doing this off and on the whole 12000 mi ,is your truck 2wd 4wd cclb,what eng mods,are u joints new has t case ever ran dry. Could be a 1000 things so the more info you can give, the better chance one of them may be able to help . Good luck!
First off I'm just hoping to get help on what the problem could be. Don't need to be ?ed whether or not Mike installed my transmission or not. Things happen and maybe something happened to fail internally. Stock cp3 ,4wd ,CAI, 4" exhaust, Ppe boost valve ,Airdog 165, intake horn,monitoring everything with edge insight. Yes it has been doing it throughout all 12000 miles. No u joints aren't new nor has t case ran dry. At idol desired and actually fp is 5.5. Not sure when it acts up but will monitor next time Thanks guys. Just want to fix it because it is annoying to drive
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