Transmission Issue

[Drazz100]

2000 gt 4.6l with automatic
First,car has 4.10 gears and previous owner didn't have the computer flashed so the Speedo is off 20 mph.
here is what it does.
some days,when you start it up,shift into R,the car doesn't move.If you rev the car a few times,it catches and might back up or will back up and slip out of R.
Same way with D.On the days the R is acting up,D will also do the same thing.
Once you get it going,it shifts fine.
It will aslo "search" back n forth from OD to 3rd and back if I am in town running about 40 mph.If i press the OD button,take it out of OD,the car shifts thru town fine.But it doesn't want to take off from a dead stop unless I give it some gas and sometimes it yanks the car.
Would flashing the ecu fix this?
Torue converter bad?
TCU fried?
Fluid is nice and clean and full.
I can shift in it in D,Press the brakes and do massive burnouts.I figured if the TQ was bad,the burnouts would be harder to do.
thanks for any help

 

[dimaiox1]

Sounds like it may be a bad clutch ring. But make sure the cable is not streched and miss shifting. May be hitting neutral instead of drive of reverse. Also on the trans there an arm the cable bolts too could be lose so. And first and fore most check the fluid.

 

[nyuk98gt]

Drazz100:

The hunting/shuffling you are feeling could just be the torque converter locking and unlocking. The PCM should be corrected for 4.10 gears, imho. For th e+99s, you can have this done with a tune. While you are getting a tune installed it would be an excellent time to adjust the shift and lock schedules. Shift points can be set by either MPH or RPM (you chose) and you really need to adjust the WOT shift points because the 4.10s will cause the rev limiter to be hit often.

I'm not trying to spend youre money for you but correcting for rear gears is pretty important.

The manual lever position sensor (MLPS) could be out of adjustment. This can cause the 'non engagement'. As mentioned, the fluid level and condition can affect shifting. If you want to know what is going on, you need to datalog (example: SCT XCal + laoptop). Once you see what is going on, it makes fixing the problem a lot easier.

HTH,

Chris

p.s.--Welcome to the forum!