Strange behavior from 4L60E

KDGAST

MEMBER
2000 GMC JIMMY
4.3L
V6
4WD
AUTOMATIC
160,000 MILES

Replaced bad transmission with no reverse and the new to me transmission goes forward in reverse. Has a new neutral safety switch and back up lights come on but wheels turn forward.

Friday, March 18th, 2016 AT 10:02 PM

6 Replies

HMAC300

MECHANIC
48,601 POSTS

It may have the wrong clutch pak applied due to damage internally. If you got it from a junkyard get another one

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Saturday, March 19th, 2016 AT 4:34 PM

KDGAST

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6 POSTS

It didn't come from a junk yard but the truck it came from was in an accident and the owner was parting it out. I personally went to his house and witnessed the truck go in every gear including reverse.

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Sunday, March 20th, 2016 AT 9:39 PM

HMAC300

MECHANIC
48,601 POSTS

Then check harness at transmission see if there is any damage there and scan for codes. Does it do this while wheels in air or on the ground? Is the transmission full of fluid? What year did the transmission come from if it was from a pre 1995? If so then it is an OBD1 and will not work with your vehicle.

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Sunday, March 20th, 2016 AT 10:48 PM

KDGAST

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6 POSTS

With wheels in air. It is full of fluid and truck was a 1999 Chevy blazer

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Monday, March 21st, 2016 AT 7:41 AM

HMAC300

MECHANIC
48,601 POSTS

What does it do when it is on the ground? The same? Tt may be just because the wheels are in air, but I kind of doubt it. But try it. If it does the same then it has either not enough pressure for reverse or a valve body problem and a transmission guy should look at it. Have you scanned for codes?