Slow 1-2 and 2-3 shift?

[03yukXL]

Hi all,

Under light throttle conditions, I notice my 03 xl will have a somewhat sloppy, slow shift from 1-2 and 2-3. It feels like it decides to shift, does a partial engagement, and then drops into gear maybe a half a second to a second later. Almost like it shifts twice. Grab and then... drop. If I am harder on the throttle or I engage tow/haul mode it's positive (especially in tow haul, it almost bangs the gears).

Any thoughts on improving the shifting? It has new fluid and filter so it's not that...

 

[afpj]

Smarter folks will chime in, but everyone who's trying to help going to want to know how many miles on the drivetrain, has anything been replaced, and with what brand? Also, when is last time you cleaned or replaced the throttle body and mass airflow sensor? The MAF does influence transmission function to a degree as the PCM uses MAF data to guide a lot of its decisions.

 

[NickTransmissions]

Hi all,

Under light throttle conditions, I notice my 03 xl will have a somewhat sloppy, slow shift from 1-2 and 2-3. It feels like it decides to shift, does a partial engagement, and then drops into gear maybe a half a second to a second later. Almost like it shifts twice. Grab and then... drop. If I am harder on the throttle or I engage tow/haul mode it's positive (especially in tow haul, it almost bangs the gears).

Any thoughts on improving the shifting? It has new fluid and filter so it's not that...

You've pretty much described nearly every 4L60E known to man. Install a Transgo SK4L60E shift kit, Corvette 2nd gear servo and Sonnax 4L60E-LB1 boost valve kit.

Check your servo travel and band clearance as well. My guess is that it's on the high side...the Transgo kit will come with a spacer to tighten it up...

 

[03yukXL]

You've pretty much described nearly every 4L60E known to man. Install a Transgo SK4L60E shift kit, Corvette 2nd gear servo and Sonnax 4L60E-LB1 boost valve kit.

Check your servo travel and band clearance as well. My guess is that it's on the high side...the Transgo kit will come with a spacer to tighten it up...

Thanks for the advice. Pretty cool that a guy of your skill level is offering advice on this forum.

Any chance you think I could just start with the servo and see how it performs?

 

[NickTransmissions]

Thanks for the advice. Pretty cool that a guy of your skill level is offering advice on this forum.

Any chance you think I could just start with the servo and see how it performs?

You're welcome. How you'd like to proceed is certainly your call but just the vette servo will produce minor gains at best. Your soft, lazy 2-3 shift wont change at all. Plus you really need the pan and filter out of the way to dial in and check your band clearance. The shift kit paired with the vette servo is what you really need to do.

Alternatively, if it has ~150k or more miles, you can elect to simply remove the trans and overhaul it so you can build it exactly the way you want it, replacing and upgrading parts as needed/desired, like the sun shell, 3-4 pack and so forth.