Jump to content

FirebirdNation.com is the premier Pontiac Firebird forum on the internet. Supporting Members do not see the above ads.
- - - - -

4L60E A/T won't shift from 1-2 w/o letting off gas pedal...

  • Please log in to reply
41 replies to this topic

#41 JoePeek


    Firebird Master Tech.

  • Full Member
  • PipPipPipPipPipPipPip
  • 1,019 posts
  • Gender:Male
  • First Name:Joe
  • City:Westfield
  • State or Province:IN
  • Country:USA
  • Year: 1971
  • Make: Pontiac
  • Model: Trans Am
  • Engine: 455 HO
  • Transmission: 4 speed

Posted Today, 01:20 AM

Good stuff here, missing bumpstops, panhard bar geometry, ABS codes. Isn't it great how we go looking for a particular problem and end up finding all kinds of other stuff, and how learning more about our 'birds is a never ending adventure. Just curious if you figured out the reason for the delayed shift? So it was not the TPS, but did it end up being the VSS? While the world of ABS is a fascinating area that needs to work right from a safety perspective. Kinda wondering how this has any effect on when the PCM commands a shift? Still great info, so who cares, but just curious if you figured out the delayed shift root cause? 

#42 Injuneer


    Just Trying to Help

  • Administrator
  • 12,339 posts
  • Gender:Male
  • First Name:Fred
  • City:East Brunswick
  • State or Province:NJ
  • Country:USA
  • Interests:Card carrying member - NHRA and AARP!

    Licensed Professional Engineer (Mechanical)
  • Year: 1994
  • Make: Pontiac
  • Model: Firebird Formula
  • Engine: 381ci LT1 stroker
  • Transmission: TH400 + GV O/D

Posted Today, 06:09 AM

If there's a connection between ABS faults and delay in the 2 -> 3 shift, I can't find it. Not to say it doesn't exist, just that I can't find it. I wish I knew more about the internal workings of the 4L60E. At least we're getting collateral benefits :D

Now that he has cleared the ABS codes let's see if the shift problem is gone.



381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74# injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor



0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users