ok so my truck decided it doesnt want to shift into O/D until im doing about 57mph, and drops out around 50mph, is this adjustable at all? most speed limits here are 45-50mph and driving around in 3rd gear is reckless on MPG's

i put this up on monteC's thread and he suggested TPS needs adjusting? i recently replaced it when i put on my 50mm TB, how would i go about adjusting it to fix this?

not really sure when this occured i noticed it after i changed a lot with the truck, wheels, tires, trans, TB, rear lift, etc etc

 

there's not really any adjustment to TPS, other than wallering out the screw holes and rotating it a tad to achieve an ideal zero point voltage of .6 or something like that? i've lost all my links, but somewhere there's a diy on that. personally i think its a waste of time.

could monte have been talking about a TV cable adjustment? that controls the sensitivity of the up/down shifts.

your truck might have something to do with the pcm's perceived speed. the OD and torque converter lock are electronically controlled.

for what its worth - with my stock pcm and bigger tires and out of adjustment speedometer, mine used to shift into OD at about 45 mph (way too low). i installed a hypertech, but it wouldn't adjust the speedo, and shifting stayed the same. i installed a superchips and it did adjust the speedo, and it did change the OD shift point up to about 55 mph, which i think is ideal, since my truck sucks in OD at low speed and low rpm.

 

i got this from another forum, it might help
tps adjustment


The TPS is on the drivers side of the throttle body (if you have the stock airbox, you may have to remove it).
then, take a digital voltmeter and stick the positive tester into the back of the plug at the Black/Orange wire...then, put the negative in the back of the black/blue wire.
With the key on, engine off, throttle closed, you should see anywhere from .5 - 1.5 volts. You want it to be as close to 1 as possible. Then, open it to full throttle, it should climb to anywhere between 3.5 - 4.5 volts.
Now, to adjust it, loosen the two bolts (do not remove them), and slowly move the TPS (spinning it) in either direction (one way will raise the voltage, the other will lower it) watching the voltage at closed throttle. As I said, get it as close to 1 volt as possible. (mine only went to .7 volts, so...you may not necessarily reach 1) Tighten it up, (not too tight, remember your bolting this to aluminum). Open the throttle fully and see what the voltage goes too...as I said, as close to 4 volts as possible is best.
Now...put her back together and let her rip

 

^ that's it, but to rotate the sensor any more than a hair, you have to drill out the mounting holes. its good to check the voltage from the sensor, but if its at that .6 or .7 volts at idle, then its correct. about all you can do is replace it.

 

ill try it, but would that really affect my O/D? anyone else have some input?

 

Tire size will do it. I had the same issue running 3.55 gears and 33" only know cures are smaller tires or deeper gears.

 

didnt do anything for me because mine was already adjusted, but ive heard people getting crisper shifts and such from it

 

i had 285's before, 305's are only slightly larger but i suppose that may have done it

and ill try it just for the hell of it, but my shifts are already amazing, the guys at aamco did a great job adjusting the valvebody and i had the shift kit installed when i got it rebuilt