Just did a 4l80E segment swap into my 2000 RCSB 2wd. I built the 94 80E and bought a new circleD 278mm converter. Everything works great. Firm shifts, good line pressures, smooth operation. What is happening is the TCC will not re engage after letting off the throttle at speeds above 65 mph. It will re apply all the way up to 65 but once past it it will not lock up. I know the 80E's all have that feature where the TCC turns off and on in respect to the throttle but it will not re engage after 65mph. S I grabbed a tech 2 and verified the PCM isn't commanding it on. I can manually override it with the scan tool and turn on the TCC so I am confident it isn't a hydraulic issue. I guess my question is what parameters does the PCM monitor that dictates when the TCC is applied?

 

is it a stock tune besides the segment swap? also does the truck have a different cam?

a few first guess is someone fudged up the lu settings and it wont stay in lu over 65, or its registering a misfire from a camshaft which would cause it to kick out.

 

Stock cam. It's more less a stock lq9. I had the PCM adjusted for the 4.10's and 28" 275/40/20's. the tune is not stock, wheatly tuned it I have been thrilled with the results since he tuned it.

 

Everything else is freakin great except for this thing with the TCC. I wonder if the ISS peters out as the rpm's increase like at highway speeds? Maybe I'll swap the VSS and the ISS and see what happens

 

you know it does have a SES light on. maybe it might be a misfire code. the thing that is wierd is it will be in lock uo at 65 them come out while i am steady on the throttle. it will not reengage until i come to a stop the go throught the gears and hit 40 again. ill check that code

 

Is this converter a single or triple disc ?
Reason I ask is. Multi disc is most definitely noticeable when locking up at any speed , and a single disc might not give the feel that the multi does ,

But I guess since your verifying you can command it to lock then I guess you are " feeling" it also ?

Did you install the different pressure spring in that usually comes with the converter ?

 

its a 278mm converter, the cheaper one. i am assuming its a single disk. it isnt a hydraulic failure since i can command it off and on with the tech2 at any time. when it is locked up i konw it beacuse when i apply slightly mor throttle the rpm's do not flare up. the tcc spring i used what ever came in the HD2 kit. its strange because it seems to nly happen on the highway

 

i know what you mean about the feel. if i am not mistaking the HD2 kit also does away with the PWM and applies the TCC at once giving you that feel of almost a 5th gear