Trouble with hot transmission
 

Hi everyone. I've got an '85 GSL 5-speed with 20,000 original miles. Minimal maintenance was performed by original owner, or at least I don't have receipts for the work done (I do have a few receipts, but its not comprehensive).

I'm having an issue with shifting. When the car is cold it shifts fine, but after driving on the highway for 30 minutes the shifter gets extremely sticky. It doesn't want to come out of gear, it is difficult to move back and forth in neutral, and it's difficult to get back into gear. Even when I shut the car off, the problem is still there until everything cools down.

I flushed the fluid from below and filled with Mobile1 75w90. It did't look all that bad. I pulled the shifter out and cleaned the bushings off and topped off the fluid on top. That made shifting nearly perfect when cold...but the same issue occurs after 30 minutes of highway driving.

What else could it be?

Possibly related, I have a vibration above 50 mph that is constant. Doesn't feel like tires, so I'm thinking it is the drive shaft u-joints. There is some gunk at the tail end of the transmission as well leaving me to think the rear seal is gone. I may pull all that out in a week or two but I need to know what to do about the transmission. Do I pull it and send to a shop? Is there a quick fix I could try before then? Thanks in advance for your help!

Is the trans noisy? Does the shift lever get warm/hot to the touch when this occurs? What did the fluid in shift housing look like before topped off,any gunk,water in there?

No gunk/water. Will have to get back to you on shifter temp, it's not hot to touch the leather, but I will check the shaft.

I had similar symptoms last year when my piolet bearing went out, but at 20k I don't see how its possible. Then again stranger things have happened.

So the shifter doesn't get hot. The problem hasn't gone away after changing the oil but after a few hundred more miles it isn't quite as hard to shift as it was initially. I'm wondering if I should flush the fluid one more time to make sure all the old stuff is out.

I its only got 20K on it and has sat this long, it could be the pilot bearing being stiff with old
grease in it. I'd give it some time to loosen up and see how it does. Worst case is it actually
fails which is not unlikely even at 20K. My failed on me at about 33K when I first got the car.

^^^ good point. I guess without daily activity things break down. Mazda didn't build a paperweight after all.