3rd to 4th shift revs down funny

[Unoid]

I'm not sure if this is tune related. I have a mailorder tune from a good guy in IL.
Intake/exhaust only.

under 20-50% throttle in third gear it usually shifts to 4th at 2500-3000rpm. about 1 second before shifting the revs drops 300rpm and slowly climb a bit again then it shifts into 4th.

Any idea why its "fake shifting" with the rpms?

 

[PhLoBuS]

Do you have OD on or off?

 

[Bird]

Sounds like the torque converter is locking right before it shifts. Transmission / torque converter shift / lockup points can get a little tricky - not really something that can be tuned via mail order.

Bird

ps. Phlobus - if OD was off, it wouldn't be shifting into 4th, would it..........

 

[Ct.TOPGUN]

It is torque converter lockup and is normal.


Jim

 

[Unoid]

So its normal? I never noticed it before, truck has 60k miles now.

 

[uncooked]

Sounds normal, mine has always done the same. :beer: