speed sensor?

[hvychy]

I have a 92 ty. Now I have to go over 40 mph. to get the truck into 4 th gear. Then after that the tc dos'nt lock up. then if I go under 40 mph the tranny slips back into 3rd. Now the first owner put a shift kit in the tranny is shifts hard in all gears. I've tried to adjust the detent cable but the same. If anyone has had the same problem please let me know how to fix or what the problem is . thanks

 

[Mephisto]

well its not the speed sensor. my sy threw a speed sensor code, and i thought i messed up some shit underneath the truck, because my odometer, and speedometer werent working. a few days later i go to pull the chip out of my truck, and notice a wire harness wasnt hooked up... :sarcasm on: i can sleep better at night now knowing, that its possible that my sy has 100k miles on it, since all you need to do is unhook a wire harness to turn off the odometer, once again a fine display of quality GM engineering :sarcasm off:

 

[myclone]

Both my Sys have/had the "drop into 3rd below 40mph" syndrome.

I think its normal for the most part. Something I have noticed is if you click the shifter into neutral and back into OD real quick the trans will go into OD at about 38mph. If the trans is cold then this usually wont work.

I know VERY little bout trans but I believe that the 3-4 shift point is governed by the governor, fluid press, and temp. Im sure J Waller or B Hartman can shed more light on this than I ever could.

My point?? IMO your trans is acting normal.

 

[0-60N4]

Can you tell me exactly where this connector is? I've been getting some speed sensor codes after changing chips.

 

[jwaller]

the speed sensor has nothing to do with shift points. it does and will affect the TC lockup though. The Myclone was correct about what controlles the shift points. governor and detent posistion is what does it.

 

[myclone]

On 2002-03-21 17:39, jwaller wrote:
the speed sensor has nothing to do with shift points. it does and will affect the TC lockup though. The Myclone was correct about what controlles the shift points. governor and detent posistion is what does it.

Whoo hoo!!! I got something right :grin:

 

[hvychy]

ok so can the speed sensor cause the tc not to lock up and still not throw a code. I have no codes showing. I just waste a crap load of gas on long trips im at 70 mph in fourth gear and im doing over 3 grand on the tach. there is just no lock up

 

[jwaller]

isnt that what I said. " it does and will affect the TC lockup though. "

 

[hvychy]

thanks

 

[V6 Kompressor]

The module that most likely got un-plugged, used to be called the drac, now called the vss buffer. this is the white, plastic module, located next to the ecm, where the pulse signal is taken from the speed sensor, located on the transmission, and through a series of jumpers, multiplied/divided and adjusted for tire size & gear ratio and sent to the dash speedometer, cruise control and ecm. This is the module that needs to be re-calibrated if you change gears, tires with a different outside diameter, ect. I got the jumper calibrations from diy-efi.org if anybody needs them...