Transmission won’t shift

[thegawd]

have you tested the tps? the throttle position sensor sends the computer info that helps dictate shifts. a faulty tps can cause a few problems. when they fail its not going to send a red flag and get a check engine light because its not that smart. it just read incorrect or no data and that screws **** up...

I'm not sure how to test on a 95 with obd1.... theres YouTube videos and they use a multimeter....

on my obd2 I can graph it with my scanner. the graph is supposed to rise nice and smooth as the throttle opens.

a new tps on my burb made me accidentally lay some rubber when I took off.

good luck

Al

 

[Slade]

have you tested the tps? the throttle position sensor sends the computer info that helps dictate shifts. a faulty tps can cause a few problems. when they fail its not going to send a red flag and get a check engine light because its not that smart. it just read incorrect or no data and that screws **** up...

I'm not sure how to test on a 95 with obd1.... theres YouTube videos and they use a multimeter....

on my obd2 I can graph it with my scanner. the graph is supposed to rise nice and smooth as the throttle opens.

a new tps on my burb made me accidentally lay some rubber when I took off.

good luck

Al

Thank you, I’ll look into it! the tps never even crossed my mind lol

 

[1997]

a TPS sympton usually causes harsh shifts, park to D as an example, slams into gear since trans is running at max line pressure, but easy to check as stated. (also cheap to replace)

did you check voltage on ECU pins E8 and 9?
it should be .4v (or close to it, when running warmed up).
if you get battery voltage on those pins under the above conditions, its getting closer to an ECU issue.

 

[1997]

link to ECU pin out, since TAGALLEN made it really easy to find.

https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/ecm-pin-out-chart-2

 

[Slade]

Sorry for the lack of updates, hope everyone had a good Christmas and New Years! This weekend I had the chance to finally work on the truck and get it driving. The fix ended up being a $3 pig tail going into the neutral safety switch. There was just the slightest crack in the wiring that I missed the first time I checked the wiring. Thanks for all the information and advice y’all have given. It is extremely appreciated!

 

[1997]

nice job and posting "the fix".

 

[PEIslander]

Yes. So many times you read a long thread and never find out what the fix was. Thanks for telling us!