Transmission problems


Asked by Aug 02, 2015 at 08:23 PM about the 2002 GMC Sierra 2500 4 Dr SL 4WD Extended Cab SB

Question type: Maintenance & Repair

I have a 2002 GMC Sierra 2500 and
before i bought it from a buddy he
drove it through a very large puddle
and it cracked his block. So we
replaced the engine and then the
tranny started giving him problems. It
would jump every time it shifted until
it finally just wouldnt drive or go into
reverse. So we replaced the Torque
converter and transmission with
another one, which was fried so he
sold the truck to me because he was
done with it. The new tranny won't go
into drive or reverse, only works in 3rd.
Ive heard plenty of reasons why, such
as the fluid pump is bad, the filter is
clogged, gears are shot and whole
transmission is done. I have two,
4L80E transmissions with the same
problem, buy a new one or is there
something i can do to save me $?

3 Answers


I'd suspect an electrical problem since this all started with the big (wet) puddle. Water can wreak havoc on the electrical system of a vehicle. Is the check engine light on? If so, what trouble codes do you have? A tranny problem can trigger the check engine light and set a trouble code. Make sure all the electrical connections having to do with the transmission are clean and tight. Check for damaged or disconnected wiring as well. HTH. -Jim


The transmission that was on the truck when it went in was replaced with what we thought was a good one. Right now the one that is on the truck isnt shifting into D or R only third.

1 of 1 people found this helpful.

Ok update on transmission. Wont engage drive or reverse but 1-3 gear works and when you get it up to ~50mph it works in D

2 of 2 people found this helpful.

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