Hey all! I serviced my trans about 2 months ago,did not effect any damage to the solonoids
and has performed flawlessly since(as it did before the service) However,now on cool mornings(40* or lower) It takes 2-3 miles for the trans to upshift into O/D! I am not overly concerned with this issue as once the trans is warm it performs wonderfully and the Jimmy still delivers 21-24 mpg! Any thoughts? (97 Jimmy- 4l60-w 4.3 -gu6 axle) 155,500 mi
THANKS ! Bill

 

Are you sure that it is not shifting into OD or is it just that the torque converter doesn't lock up fully until the trans warms up. If it is the latter, then it may be normal.

What RPM is it running when you think it is supposed to be in OD and what RPM is it running when it is in OD at say 60MPH for both?

 

Hey! I am getting torque converter lock at about 38mph (1400 rpm) but the unit will remain in 3rd hi to about 2200 @ 60mph at which time as I said it will drop into O/D and read the usual 1800 rpm or so.

Anyway I am taking the unit on a 1500 mi trip for Thanksgiving and since it is only a 2-3 mi cold issue,I have no real concerns,just was wondering if any one had experienced the same issues...Car runs awesome and I have less than $2K in it and it is a solid #3 vehicle-looks new from 30 feet! Thanks in advance for any further input! Bill

 

Those numbers sound an awful lot like typical lockup to non-lockup RPM differences.

What is your RPM at 60MPH when in 'D'? If you are correct, and the trans isn't shifting into OD when cold, it should match your previous 2200RPM. If ~1800RPM is the engine speed when driving 60MPH locked into OD, then the engine speed when locked in 3rd gear should be 2500-2600RPM since 3rd gear is a 1:1 ratio while OD is a 0.7:1 ratio.