R-N-D-3-2-1 All act like a weak 1st gear

hylexer

Newbie
Joined
Sep 24, 2022
Messages
4
Points
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Make
Chevy
Model
1500
Year
2002
Miles
?
Engine
?
I found this website through a google search. What I have is an '02 Silverado 2wd. The problem the truck is having is that every gear acts like a very weak 1st gear. No matter what gear I shift to, the truck wants to go forward, very weakly. The motor is not original, nor is the transmission.
I sometimes have to run it up to 6k rpm to get some movement, sometimes the truck is just ready to go.
Sometimes the R-N-D may act a little different power wise from each other, but they all act roughly the same, a very weak first gear.
In reverse, the backup lights do come on, but the truck still wants to go forward.
The gear selector on the dash doesn't always read right, sometimes it shows R when you're in park, but the ignition/key recognizes you're in park. And sometimes the dash readout doesn't show the right gear you're in, in general.
The truck does go into park, and park functions properly.
The ignition does realize whether you're in Park or Neutral to start it.
The motor and transmission have both been replaced. I know that when the transmission was replaced, things weren't exactly the same, and some parts were put together for it to fit. But the truck drove fine for about 1 year like that. And suddenly one day, the transmission just didn't act right.

This truck was mine, then it was my dad's, and now that he's passed, it's back to me......after sitting for 3 years. I would almost let this truck just go, but it has some sentimental value.
 

grcauto

wrench
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May 29, 2014
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48
You need to start by adjusting the selector switch.
 

grcauto

wrench
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If you have a scan tool that will read it you can adjust it until it reads it correctly and also displays correctly, When it's out of whack the shifts are funky big time. There's also a procedure to do it without a scan tool or you can mess with it.
 

hylexer

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If you have a scan tool that will read it you can adjust it until it reads it correctly and also displays correctly, When it's out of whack the shifts are funky big time. There's also a procedure to do it without a scan tool or you can mess with it.
What kind of scan tool would that be?
 

nickb2

Wrench. Diagnostic Tech.
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Nov 22, 2008
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What kind of scan tool would that be?
Here are a few logical options that would suit what your looking for.

Something with live data, that will show actual trans line pressure. I know for a fact you can get this online for cheap.

Just need to do a bit of research on how to setup tis 2 web thing, and presto, cheap laptop option with dual go stuff.

 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
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Location
St-Hyacinthe, Quebec, Canada

hylexer

Newbie
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Sep 24, 2022
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Small update. The gear shift moves into park, but the selector on the dash won't show in Park, and the wheels spin freely. When the gear shift moves to what should be Reverse, the backup lights do come on, and one-time earlier the wheels actually jumped backwards for only a moment, then I could hear something underneath, and the wheel stopped almost immediately. Shifting to what should be Neutral, the truck does idle up, but maybe the wheels spin forward, maybe they don't.

On the gear selector on the side of the transmission, there is an ?8? pin connector. One of the wires coming out of the top hasn't been reconnected and is just taped up.
 

grcauto

wrench
Joined
May 29, 2014
Messages
1,218
Points
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Small update. The gear shift moves into park, but the selector on the dash won't show in Park, and the wheels spin freely. When the gear shift moves to what should be Reverse, the backup lights do come on, and one-time earlier the wheels actually jumped backwards for only a moment, then I could hear something underneath, and the wheel stopped almost immediately. Shifting to what should be Neutral, the truck does idle up, but maybe the wheels spin forward, maybe they don't.

On the gear selector on the side of the transmission, there is an ?8? pin connector. One of the wires coming out of the top hasn't been reconnected and is just taped up.
That needs a proper repair.
 
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