1998 Chevy Tahoe Full Throttle Shift

1998 CHEVROLET TAHOE
198,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
JRAMSEY
  • MEMBER
  • 1 POST
My tahoe has 197000 miles on it. Just had a new motor installed, water pump, intake plenum, hoses, radiator, and front seal on the trans. My question is at full throttle the transmission dont want to shift out of first into 2nd unless I lift to about 3/4 throttle, then it shifts like it normally should. Any advice will be appreciated.
Apr 20, 2009 at 10:52 AM
Advertisement
Avatar
PEAR69
  • ✓ASE Certified Mechanic
  • 1,482 POSTS
  • ASE Certified Mechanic
The timing MUST be perfect on these engines. The timing CANNOT be set with a timing light or BY EYE. Just because the engine may seem to run good does not mean the timing is correct at all rpm ranges. The computer sets all the spark advances and retards. For this reason - the only way to check and correctly set the timing is by using a scan tool that is capable of this proceedure. This usually means a trip to the dealer or a mechanic with a MODIS scan tool or a GM TECH ONE scan tool.
Once the timing is correct - replace the tranny fluid and filter with the Valvoline high mileage tranny fluid. If all this does not work, You probably have the infamous sticking 1/2 shift solonoid valve issue..
Apr 27, 2009 at 9:22 PM
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.