Chevy and GMC Duramax Diesel Forum banner

Abrupt shift from 1st to 2nd and 2nd to 3rd - 2006 Duramax 3500

945 views 7 replies 3 participants last post by  KP616 
#1 ·
I have a 2006 GMC Savana 3500 Duramax extended cargo van with 132,000 miles on it. I bought it new and am the only owner. I used it mainly to haul my dirtbikes in and drove highway miles with the occasional haul of my CAT 259B skid steer machine on a flatbed trailer (roughly 9,000 lbs total haul weight).

About 10,000 miles ago I came to a stoplight after already driving for about 30 minutes. When I accelerated from the stop light, WHAM, I felt like I had been rear ended. Turns out it was an extremely abrupt shift from 1st to 2nd, and a little less abrupt from 2nd to 3rd. Come to another stop light and did it again when accelerating from a stop. Decided to ease the vehicle home and let it sit. Took it to shop on Monday, it didn’t act up on the way there and check engine light never came on. The shop drove it around and never got it to act up again, also there were no error codes when they hooked it to computer.

I’ve since been driving with no problems for about 10,000 miles and now it’s back. Randomly occurred again after driving for 30 minutes or so and accelerating from a stoplight. Now the check engine light came on, code P0700. It happens sporadically, seemingly after the transmission warms up. But if I pull over and turn the vehicle off for a min it will go away, and eventually come back miles later. It did briefly go in to “limp mode” where it seemed stuck in 3rd gear and would only go around 55 mph, but then it cleared when restarting again.

TCM issue? Torque converter issue? Solenoid issue? Please help!
 
See less See more
#2 ·
Get a better code reader as the p0700 code is a generic code to tell it to light MIL, there should be another code or more with more specific info.
 
#4 ·
Can you clarify? What do you mean by "abrupt" shift? Did it shift early (like in 3rd at a low MPH? or a HARD shift? and normal speed and RPM when it did shift. A 'hard' shift would kind of indicate to me possibly the convertor clutches might be trying to apply in gear changes. Have you tried using Tow/Haul to see if that makes any difference?

No matter I would suspect a valve body / solenoid issue. One of the guys reently found a chaffed solenoid wire INSIDE the trans pan causing all sorts of erratic shift issues.
 
#7 ·
Sounds to me like convertor is locked up,, but as I understand it , it should NOT be on the 1-2 shift even if the tow/haul is activated. Wiring or maybe the convertor lockup solenoid in the trans??
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top