agreen

98 body, 4.0, originally 2wd auto and converted to 5 speed 4x4 with a 1990 ax15.

It's been doing great since the swap back in March, but just yesterday I got the most awful grinding noise when I came to a stop. Pushed the clutch in, went to put it in 1st and it ground. Horribly. I thought I had a hydraulic issue, but the master and slave are both brand new (well, 2 months)

The more I got to thinking about it, it seems like the reverse idler was slightly engaged. If I tried to select any gear when stopped, it would grind. I killed the engine, selected 1st, fired it up (clutch in) and the grind was still there. I killed it, selected reverse, started it, had no grind. I popped it out of reverse and went to put it in another gear, got another grind.

This happened right when I got to work, so I went inside and grabbed a coworker. He comes out to listen and the noise wouldn't happen. Didn't matter what gear, it wouldn't do it. Then it did as he walked away. We tried to troubleshoot while it was doing it, but it only happened one time. So I gave up and went back inside. The drive home after my shift was smooth and quiet. Today's trip to work was also completely noise free. I've seen some forum and video talk about rebuilding the trans and having to replace the idler, which got me wondering if it's more common than it sounds? I know every person can't be so bad at driving a 5 speed that they try to put it in reverse after 5th... Seems like there might be something up with a detent or my shift selector shafts. Just sucks that I'll have to tear it back out to find out.

It's definitely going to be a little while before I can pull it out and apart. I did check the fluid level, then drain/refill it with another 3.5 qts of syncromesh. The white rag check on the way out didn't show anything crazy, just a little bit of dirt or fine particulate, but nothing that suspicious.

Guess I'll report back if/when I find something. Anyone ever had something similar happen?

lawsoncl

When mine did that, it turned out to be the pilot bearing in the end of the crank. It also would creep forward with the clutch pushed in and in gear. Happened about 30k after I rebuilt the transmission. I didn't touch the pilot bearing or clutch since I found a receipt that the previous owner had just done them. When I bought it, the dealer told me "it just needs a clutch", and it turned out to be the synchros. I'm not sure if the dealer knew the truth.

agreen

Damn I really hope it's not that. I had to use a Novak adapter pilot bushing since the engine is a 98 and the transmission is a 90. They use oilite bronze for the bushings too, so it'd be real hard to believe it's the culprit. Only one way to find out I guess. I drove it all around town today with zero problems. Idk what is going on. If I had the time I'd take it apart right now, but my backup car is taken apart. I guess I better get crackin on something.