I don't know if it's just me being paranoid but the tranny shifts fine no problem. The issue is, is once I reach 55 mph my Rpms will drop to around 1500. Like I'm getting up to speed shift Rpms rise shift Rpms still climb normally n then hit 55 n then boom it drops suddenly. Am I being paranoid or is there a tuning issue or what. I have a 3600 stall in it.

 

It is normal for the lockup clutch (TCC) to engage at that speed and drop your rpms by 150-200 rpm. If its dropping by e.g. 500, then your converter is too loose or your fluid is too low.

Am I answering your question?

 

I'll check the fluid levels in the transmission. But yes you are answering it. And what would cause the converter to be too loose. Should I get another stall?

 

I checked the tranny the level is good, I'll post a video later on so you can see exactly what it's doing.

 

Theres a video of what teh car does. Shifts fine but it goes really high in the Rpms then drops to 1500 ish after 55 MPH

 

Anyone. I believe it became more noticeable after I did a fast 92 nw 92 upgrade from the ls6 intake.

 

Looks pretty normal to me for a 3600 stall. It's just the lock clutch engaging like it's suppoed to.

 

Ok I'm just being paranoid thrn

 

Isn't that just overdrive? My car does it, but it does it at 40mph. I assume it's your tune, but I'd like mine set up a little higher because I have 3.27's and a big cam.

 

Any transmission gear ratio under 1.00 is consider "overdrive"; therefore 4th gear (ratio of 0.70) in a 4L60E is overdrive. Lockup is completely independent; it locks up up the converter so there is a direct connection between the engine and trans with no fluid coupling. In theory, lockup could be engaged in any gear, but it is commonly only engaged in 4th gear when a certain speed is reached. It could be as low as 40 mph, but with a performance cam, you might need between 50 and 55mph to prevent surging at low rpms. And yes, the Tune determine when lockup is engaged.

 

Good info, so thank you! Yeah my car has a 232/239 with my long gears it would be nice to raise the mph up a little. Doesn't surge, but you can't give it a lot of throttle when it drops down to 1400 while driving. I'd like to raise the mph up a little, but not as high as the ops.