Torque Converter Problem - Or Is It?

[albi1cnobi1]

O.k., so here's my story. 99 Mounty, 5r55e tranny, at about 180,000 she developed the dreaded 2-3 shift flare. Replaced VB with a rebuilt unit as well as a new separator plate with bonded gaskets. Fixed my problems, tranny shifted like new. All shifts were almost seamless and TC performed as it always had, locking up when shifting into OD. Fast forward 20,000 miles. I went from stock size tires to 32's. I had originally thought I had 3.73 gears but had read the tag wrong, I have 3.55's. Since the new tires I have noticed that I have trouble maintaining highway speeds, like I need more pedal to keep it at speed. I also now find the TC is not always locking at the OD shift, usually after, and it seems as if I need to let up slightly on the pedal for it to lock up. And main thing I've noticed is when driving at highway speeds for a while the TC unlocks and the OD light starts blinking. Shutting off the truck clears the light, but the code is 741(I think) TCC circuit stuck off or malfunction. If I turn off OD the TC locks up and works fine. I'm getting ready to change my gears to 4.10's which according to my calculations should put me pretty darn close to stock. I guess my question is does anyone think the combo of 3.55's and 32's have caused this problem? And do you think the 4.10's will fix this problem? I'm open to all opinions and suggestions. Any insight would be appreciated. Thanks.

 

[drdoom]

4.10s won't fix it, you'll likely need other repairs like maybe a torque converter or maybe some valve body work or both.

 

[albi1cnobi1]

Valve body and all solenoids were replaced about 20k ago. Might tend to agree on the TC though. I guess only time and gears will tell. My theory of the gearing issue is based on this: TC lock up is contingent on several things. Mainly, TPS input, OSS sensor, and VSS input. The computer uses these, among others to control the TC lock up. If these inputs aren't in sync, so to speak then the lock up is affected. Just my theory anyways.

 

[albi1cnobi1]

bump

 

[drdoom]

I would think the TPS, OSS, etc. would throw specific fault codes aside from the 0741. From my own experience, I recommend replacing the torque converter & the seal on the pump stator. So then you have it all out, so might as well put a kit in the transmission, and flush the coolers too.

 

[albi1cnobi1]

I'm inclined to agree with you about the torque converter and pump seal. I was thinking of doing this before, only because of mileage. The VB was replaced with with a rebuilt a short time ago, including solenoids so I'm thinking I'm good there. I've been wanting to do the gears anyway, so I am going to do that and see where that takes me. My guess is it is going to take me to a new TC and pump/seal. Thanks drdoom.