Lockup in 3rd too early on 03 (48RE)

[BILTIT]

So ever since i have purchased this truck it has done this occasionally.

It goes through the gears fine until its in 3rd and locks up way to early (~60kmh/40mph) for about 3 seconds then unlocks and carries on until it gets into OD (i am assuming this is lockup and not OD when this happens but i could be wrong?). When it does this (usually once or twice a day to/from work) i just let off for a second and get back on the throttle and it shifts as per normal.

It seems to do it more when lightly on the throttle, if i am heavier on the throttle it doesn't do it.

Cold or hot fluid doesnt seem to change anything. I recently adjusted the TV cable and am just fine tuning it now (backoff one more notch tomorrow).

I have changed gov sol/transducer, tcc/lockup solenoid pack, flushed oil and have a smarty installed (pretty sure it did it before the smarty but i could check that).

Looking at places to start as this is getting annoying, especially when my son or gf drives. Any tests i can perform?

I have a smarty touch so am able to log some things or can take a video if it helps.

 

[BILTIT]

Anybody want to take a stab at it?

 

[promisedland]

Not sure, but one thing to that will help you know when lockup happens is a led light wired in that lights up when the TC locks. I love mine.
Sorry I can't help but maybe this will help a little

 

[BILTIT]

I will look into that, thanks!

 

[JKosten]

A complete stab at the darkness, but have you checked the calibration on the TPS? The PCM may be thinking you have a lighter load in 3rd so if locks the converter in early.

Here is the description of the TCC logic from a service manual: The torque converter clutch is controlled by the Powertrain Control Module (PCM). The torque converter clutch engages in fourth gear, and in third gear under various conditions, such as when the O/D switch is OFF, when the vehicle is cruising on a level surface after the vehicle has warmed up. The torque converter clutch can also be engaged in the manual second gear position if high transmission temperatures are sensed by the PCM. The torque converter clutch w ill disengage momentarily when an increase in engine load is sensed by the PCM, such as when the vehicle begins to go uphill or the throttle pressure is increased.

 

[BILTIT]

Hmmm interesting, I will look into the TPS also.

Thanks!

 

[Bob4x4]

The Smarty produces more torque at a lesser tps setting........

 

[promisedland]

The Smarty produces more torque at a lesser tps setting........

Would this be affected by diff Smarty PoD settings?