Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

Recommended Posts

Hi,

I have a strange question.  I picked up a 2005 GMC Savana with the 5.3l, and about once per week, I will get a strange 1-2 upshift. It comes off the line from a stop with the engine revving higher than normal, almost like it's half in gear.  Then it seems to catch and shift like normal.  I have tried engine braking in the parking lot and it doesn't seem to be slipping.  Fluid is topped off and pinkish.  Any ideas on what could be causing it?  No codes.

Share this post


Link to post
Share on other sites

1500?  probably has a 4L60 transmission.  Sounds like maybe the forward clutch is slipping, might not set a code until it starts to happen more often.  Maybe oil pressure in the transmission is low.  Sometimes you have to put some more miles on and wait and see if it sets a code.

Share this post


Link to post
Share on other sites

That's kind of what I was thinking too.  It is a 1500 with the 4L60e.  I will double check there are no codes with my Tech2 and post if anything has changed since the last time.  If the tranny gives up the ghost, I kind of want to swap an 8.1L or a Duramax in here.  😁. I dislike the lack of torque that the 5.3L has down low.  

Share this post


Link to post
Share on other sites

If it is indeed a 4L60 (I know some 2500/3500 vans come with the 4L80), it is most likely the 2-4 band that is worn and slipping. The forward clutch wouldn't be a culprit as it comes on in 1st gear and stays applied through all the gears. The only mechanical change from first to second gear is the application of the band, which stops the input drum and sunshell from turning.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.