Shifting issues when shifting into third gear

1988 GMC C3500
130,000 MILES • 7.4L • V8 • 2WD • AUTOMATIC
Avatar
COLOSSUS
  • MEMBER
  • 1 POST
My truck is hit or miss whether it will shift into third. Has a 454 mated to a TH400 three speed transmission. The linkage on the frame that connects to the trans has been modified and causes the gear indicator on the dash to be off. It has transmission fluid and the governor has been looked at and cleaned. Anyone have any insight on the possible issue before I start ripping it apart?
Jan 9, 2017 at 5:22 AM
Advertisement
Avatar
HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
I think you answered your own question with the linkage. this truck should have a four speed not the 400. so see if you can get it adjusted better and then if it has a throttle cable make sure that is good as well as a good vacuum source to modulator on passenger side. finally make sure there are no mounts broken like engine or transmisson.
Jan 9, 2017 at 6:51 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.