1979 Jeep Cherokee Transmission Question

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Pgamen
Posts: 1
Joined: Fri Jan 31, 2020 9:45 am

1979 Jeep Cherokee Transmission Question

Post by Pgamen »

My first post on here, please direct me if this is in the wrong place.
I have a question about my 1979 Jeep Cherokee with automatic transmission. While getting unstuck from some snow the other day I was spinning my rear tires and heard a clunk from my transmission and lost all gears. I was able to shift the high/low lever on the floor in front of the drivers seat to low and was driving again. I'm trying to diagnose what could have happened and what the fix would be. I'm guessing I sheared a pin or something that holds the high gear???
In neutral I can shift from low to high and you just don't feel any engagement. Anyone have any diagrams to show what could have broke or any experience with fixing something like this?
Any help would be appreciated

will e
Posts: 5096
Joined: Sat Aug 18, 2012 8:21 am

Re: 1979 Jeep Cherokee Transmission Question

Post by will e »

Welcome to the board! You've come to the right place.

If you were able to drive with the transfer case in low then it's not the transmission.

You have a quadratrac transfer case right? You mention the rear tires spinning, what were the front tires doing? Do you have manually locking hubs?

I am having a bit of trouble following along with what you are shifting when.

"In neutral I can shift from low to high and you just don't feel any engagement. Anyone have any diagrams to show what could have broke or any experience with fixing something like this?"

If the transmission is in neutral when you do the TC shifts you won't really feel any engagement.

If the truck will move under it's own power in with the transfer case in low, try this: Drive forward to about 5 mph. While you are still rolling move the TRANSMISSION into neutral. While you are still rolling try shifting the Transfer case back into high. It might take a pretty good 'shove'. Once you've got the lever as far as you can, try shifting the transmission back into drive and see if the truck can move under it's own power.

If it won't then you've probably got a TC linkage problem. This would explain the 'clunk' you heard, if the linkage is off sometimes it will jump out of its position, especially under load.

There are a lot of folks who are really familiar with this TC on this board and they will jump in with more info.
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hagar
Posts: 19
Joined: Sun Dec 31, 2017 9:42 am

Re: 1979 Jeep Cherokee Transmission Question

Post by hagar »

You most likely have stripped the splines on/between the reduction unit main shaft and planetary sun gear.
Try to locate and exploded parts diagram to visualize what I'm talking about.
From your description, that would by my guess.
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tgreese
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Location: Medford MA USA

Re: 1979 Jeep Cherokee Transmission Question

Post by tgreese »

Yes, if it moves in low range, it's a transfer case problem, not the transmission.

Not an expert - however... Re the above hypothesis (from hagar) isn't low range always accompanied by emergency mode with a Quadratrac? In that case, the splines in the cones could let go and the Jeep would still move in 2WD in low range or in e-mode, and not in full-time.

Jubilee Jeeps has a very informative Quadratrac page http://jubileejeeps.org/quadratrac/index.htm - suggest you read the whole thing.

There's lots and lots of old posts about this here and at ifsja.org
https://www.google.com/search?source=hp ... rn+splines
https://www.google.com/search?source=hp ... rn+splines
Tim Reese
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