Chaos07

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.

mrvedit

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?

Chaos07

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?

Chaos07

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

Chaos07

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

Chaos07

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

chikn305

iTrader: (8)

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

Chaos07

Ok I'm just being paranoid thrn

flattusmaximus78

iTrader: (1)

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.

mrvedit

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.

flattusmaximus78

iTrader: (1)

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.