Transmission wants to pop out of 3rd gear when you let off from the throttle hard. Transmission shot? Or is there a way to combat this?

 

Common transmission problem due to worn out bushings in transmission. Internet search should tell you all you need to know. T18 is easy to rebuild.

 

Unlikely.....it could be shifter pins, etc...typically not expensive parts.

 

Thank you. Appreciate the advice.

 

Could be worn sychros too.

 

Is this something that can be fixed thru the top cover without pulling the trans? Or can it be held off until I need a clutch, that is on its way out, without further damage?

 

It could be a worn shift fork. It usually will pop out of gear if it isn't fully engaged and that could be the fork being worn.

If it is a fork you may be able to do it in the truck. Could be a worn or sticking detent also. Pull the floor cover and see if you can access all the bolts. Make sure it is in neutral when you remove it.

You can drive it but try not to do what makes it pop out. And yes it can cause further damage, just baby it. If the issue is with any of the rotating parts then the trans has to come out and be torn down.

 

OP. take a look here. Borg-warner-T18-rebuild-thread http://www.earlycj5.net/forums/showt...rebuild-thread

There are LOTS of T18 rebuild threads on the net.