TH400 Transmission Won't Engage

tuekwik

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Just bought a 72 AMC Jeep J2000 4x4 with a 360 and a TH400 transmission. It hadn't run in over 15 yrs according to the previous owner. Got the engine to run but the transmission will only run rough for a few minutes then it will not go into any gear. No forward, no reverse. Once it cools down for a bit it will engage for a minute or so then back to not engaging. Plenty of oil, red and clean, does not smell burnt at all. Any advise would be appreciated. Thanks.
 
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Bert is my name

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Drop the pan and make sure the filter is fully seated and sealed. If it isn't it will suck air and give you the symptoms you describe. You can also loop the cooler lines together to verify that the cooler isn't plugged. Beyond that its probably an internal problem like a bad seal or stuck valve.
 

Bert is my name

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Sitting long term is bad for seals. They dry out and stick. As soon as you fire up the vehicle they take themselves out. You will probably be chasing leaks for awhile.
 

tuekwik

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So I finally dropped the pan and nothing really stood out. No broken parts or metal shavings or any material visible. Noticed that the oil had a milky color to it. Lots of sludge at the bottom of the pan. I did notice that the filter was kinda hanging there, I pushed it up with my finger, a good inch of play. The bolt that holds the filter was tight.Good sign? Bad sign?
 

tuekwik

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Just did some research, apparently that slop in the filter is the way that GM engineered the TH400. I also read that some people shim that filter with a pair of washers. Others say it doesn't matter that it has play cause the filter is submerged in transmission fluid so no way it will suck any air into the lines. So there's that.....
 

tuekwik

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Problem solved. New oil and filter do wonders! Thanks for the help!
 
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