Thechevyman122

iTrader: (3)

Long story short 98k miles on a 07 tahoe 5.3L 2wd and my transmission blew up on me. I had it and my torque converter replaced for $1700, and the transmission is great...But the torque converter just isnt right. It locks and unlocks at 60-70 and I can feel it locking and unlocking around town.

The stall they went back with is 1397RPM and too me it feels like that may be too low.

What is the factory stall? My gut tells me its around 1650?

Thanks
Owen

Vortec350ss

iTrader: (20)

The stall speed really shouldnd effect it once it is locked or trying to maintain TCC lock up.

What does RPM go to when you mash the throttle from a stop? Was it a factory converter they put in for you?

Thechevyman122

iTrader: (3)

Its NOT a factory stall. Thats why my thread is wondering what the factory stall is. From what I have read online factory stall is around 1650-1750.

Apparently my old TC was "loose" so they changed it with a stall that is rated at 1397 rpm.

I rarely, IF ever, felt my old TC lock up. Now I notice it locking alot around 55-60 then unlocking again if I apply any more throttle to get it to 75 ish. Once its at 73-75 it is fine. I also notice it locking unlocking alot more in town 35-50.

Its not spontaneously locking and unlocking, it is all tied to how I work the throttle, but I'm not driving any different, its just like the TC is stalled wrong, or it has a bad solenoid or something.

Atomic

iTrader: (42)

Sounds like its the wrong converter for you. I think you are right with a factory one being 1700 or so.

Thechevyman122

iTrader: (3)

Well heII. Thats what I thought, but what an inconvenience.

cams 98 silverado

Why not call a dealership, get a factory stall part number, factory stall speed, and then go to your shop and ask them the part number they used, and the rated stall speed. If it were me, I would ask them to realize their mistake and have them correct it. yeah, your going to be out a vehicle, but they did not provide a stock stall speed.

i guess I should ask, if you asked them to give you anything other than factory spec parts?

They will have to look at their PO's to trace the part number T-verter but still, if you wanted a factory stall and trans, they did not measure up.

i always wondered what a large vehicle would feel like with a tighter stall. Are there any consequences for having a tighter stall?

Vortec350ss

iTrader: (20)

I would think it'll be even less light on its feet and feel more clunky going in and out of gear. Imagine all the benefits of a looser converter from one of the sponsors and move in the exact opposite direction.

Atomic

iTrader: (42)

My converter is tight as ****, but thats on purpose because my setup makes peak torque hard and early. "Normal" converters were not tight enough and I was loosing a lot of power through them (like 15-20% loss). It hurt spool time some, but helped out top end power big time.

It is noticeable at idle (high engine load), but is great to drive otherwise; no dealy between engine rpm and vehicle motion.

Thechevyman122

iTrader: (3)

Alright so I have figured it all out. GM oem TC is a 1397 "low stall unit", Which translates to about a 1600 rpm Brake and Gas mash. My new unit is a little less, but its not broken in. Ultimately the difference that I am experiencing is due to PWM delete.

On a stock 4L60e the factory uses something called pulse width modulation (PWM) to alter the way the torque converter clutch applies and releases. This allows for partial engagement and release for smoother transmission operation. It can be deleted by altering a control valve in the valvebody. When it is deleted you will feel the lockup apply much more firmly and completely. It saves wear and tear on your torque converter clutch.

So annoying, but better I guess.

01WS6/tamu

iTrader: (36)

You'll get used to it and it does help I delete pwm on all my trans I want a solid lock. But you can always re enable pwm.