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weird shifting

matuva

matuva

Tropical 6.5er
Messages
1,996
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Location
New Caledonia. An island in south west pacific, cl
on a 1994 K1500, shifting from 1st to 2nd is rough. We can easely fell a choc while it shifts.

2nd to 3rd is a lot less rough, 3rd to OD is OK.

Couldn't read any code as my GMTDScantech license has been deleted.:eek: Probably after I updated my laptop from XP to 7.
Stefan will send me a new one.

We did remark that, with tranny on P position and engine idling, if we step the brake pedal, the speed needle raise up to 60 kph, and the odometer runs like crazy, sometime increasing, sometimes decreasing :confused:
Brake pedal released, speed drops down to 40 kph and odometer slows a lot or stops running.

Do you think it's rather an electrical gremlin than the 1st-2nd solenoid in tranny ?

Other than that, she runs fine, except sometimes she experience random stalling or no restart...
 
The VSSB module may need to be replaced, although I dont know the failure rates on those.

It will impact the speedo, as well as shift points. If you use the free version of GMTDScan you can monitor PCM vehicle speed and speedo, see if they track the same and also compare to GPS. If any are way off then shifting will be bad. Also monitor throttle position and see if it seems about right to your foot. TPS% plays a huge part in determining tranny pressure and shift compensation pressures.

If you just need to correct the speedo for some off the wall tire tire size you can put some dip switches in like I like to do, or just change the jumpers. Reference this website http://www.tbichips.com/drac/
 
I know you probably have checked the grounds(you're no newbie), but sounds like ground/electrical issue. how about alternator voltage, pos,neg cables good as well as both batteries good.
 
Yup, I, agree with you, sounds electrical...I told the guy to check all grounds.
I haven't seen him yet so I don't know what's going on. He's gone fishing for the week-end (sunny and no windy days :coolgleamA: )

I hope at least he will bring me a lobster :D
 
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