Shift fork wear

4x4M38 · Post by **4x4M38** » Tue Jan 17, 2017 9:49 am

I've been working with Oilly for advice, but wanted to bump this subject as other folks may run into what I have.

With all of the wear on my T90 due to metal shavings in the oil, and no clutch, my shift forks are notched pretty good where they fit into the gear recesses. Is it possible to file them down to remove the sharp edges, or do the wear surfaces have to be perfectly flat?

Hope this question makes sense.

Tks,

oilleaker1 · Post by **oilleaker1** » Wed Jan 18, 2017 5:25 pm

They were machined flat when new and you can see where this original surface is. If it's close, don't worry. However, you do not want to subtract by filing. Add if anything. New forks are your best avenue, or good used. When the selector rod moves the fork, the wear equates to not as much travel into gear. Loose forks equal the same. I was wondering how you were coming on your tranny. Haven't had daily questions and pictures for a while. felt abandoned-------

4x4M38 · Post by **4x4M38** » Wed Jan 18, 2017 5:40 pm

My Bad!

We were out of town for Thanksgiving, then getting everything ready for Christmas, then a continuous stream of family from Christmas on through New Year.

Finally had a couple of days to catch our breath, and me to make a list.
Also had to save up some coin for all of the T90 stuff I was going to need.

Now only waiting on Brown Santa to arrive, then you can anticipate a few
"Ahhh, it won't fit or won't work!" calls!

I've got the replacement case pretty cleaned up. Trying to finish cleaning up the outside. Need to paint before assembly but we only had two decent days and now its cold and rainy again.

I've seen new forks going for 20 to 40 bucks a piece. That seems steep for what I need. Maybe get a couple of good photos of mine to look at?

Take care,

oilleaker1 · Post by **oilleaker1** » Wed Jan 18, 2017 5:45 pm

Pictures and emails-------we'll be in the groove again.

Check for looseness on the selector/shift rod while you are at it. just let me sleep at night OK?

4x4M38 · Post by **4x4M38** » Wed Jan 18, 2017 6:49 pm

What's sleep??

4x4M38 · Post by **4x4M38** » Thu Jan 19, 2017 9:15 am

Photos of my shift forks.

1st/Reverse:

http://willysmjeeps.com/v2/modules/gall ... tfork1.jpg

http://willysmjeeps.com/v2/modules/gall ... tfork2.jpg

2nd:

http://willysmjeeps.com/v2/modules/gall ... dfork1.jpg

http://willysmjeeps.com/v2/modules/gall ... dfork2.jpg

I slipped the clutch and the other ring over the forks in some feeble attempt to determine the gap. It looks like 1st/reverse has about .025
gap, and 2nd has about .012.

Both do not wobble on the shafts. 2nd is tight, but 1st/reverse slips back and forth a little which seems to point to the hole or the pin being worn.

A little hazing on one shaft where it slides in the housing. No scoring or scratches. Looks like that should polish out.

Thanks for looking.

oilleaker1 · Post by **oilleaker1** » Thu Jan 19, 2017 9:35 am

I don't see anything that would concern me. Looks normal. The riveted pins holding the forks to the shift rods, get loose and let the fork move in the holes the pins go through. I've had pretty good luck with new roll pins and a safety wire through the roll pin. You have to move the shift rods back until they let the poppet balls and springs out by removing those pins. A pain in design. I guess they figure you will never need to. Good part is you can take the shifter off and go to your work bench to do it. I'd try the shifter out before you leap into that. When will you test drive your Jeep?

4x4M38 · Post by **4x4M38** » Thu Jan 19, 2017 10:14 am

Morning John,
So, .025 is not too much gap between the fork and the shift ring on the clutch? I guess theoretically, nothing is supposed to be rotating or all rotating at the same rpm when you are doing this, so wear should be minimal?

I was looking at that one fork where the wear extends down below the bearing surface. And a worn pin could allow the fork to work back and forth on the ring.

If its ok I'll just plan on cleaning everything up and putting it back together with the kit.

Test drive. I need to get this back together so I can put the D18 on the bench. Then we'll see. Same zombie blood in both, but I'm hoping the majority of the heavy metals stayed in the tranny. I have not pulled the inspection cover yet. Not afraid to, but......

One thing that has me a little skeered is the output shaft where it went into the transfer was pretty pitted. I'm hoping that is an anomaly.

I mean the thing WAS driving. Nothing locked up.

Any advice on breaking the nuts loose on the flanges on the D18? Saw one recommendation to take the whole thing to a tire shop with my socket and have them break them loose with an impact gun. I tried manually doing it on the shop floor but all that happened was my head went down, my back side came up, and nothing else moved.

Thanks for the help.

oilleaker1 · Post by **oilleaker1** » Thu Jan 19, 2017 11:00 am

The fork is not supposed to rub hard again't the ring. It would totally wear out if it did. It basically moves the sliding 1/rev. And syncro collar into gear, all the way. Once in gear, torque on the gear holds it in for the most part, and the poppet balls located in the sector shaft cutouts, hold the fork in position. A bad gear like 2nd, that slips back almost out of gear, can be put back into gear by stepping on the gas. No kidding. I'd check the fit of the rear drive gear on the back of your mainshaft. If loose, replace both the Mainshaft and rear drive gear. It will hammer and make noise if loose. Your transfercase should have intermediate shaft wear with all that metal that floated around. Kit it. Output shaft bearing roughness.. etc. Use a air or electric impact wrench on the yokes.

4x4M38 · Post by **4x4M38** » Thu Jan 19, 2017 11:23 am

Hi John,
That's what I thought. I'd bet the wear is due to Bubba shifting with no clutch.
what was the old line? "Grind it to fit?"

I'm replacing the input shaft, main shaft, 1st gear, 2nd gear, idler shaft and gear, the full synchro, and both bearings per your recommendations.

I'll take a look at the main drive gear fit when I get the new main shaft. It wasn't loose on the old one.

oilleaker1 · Post by **oilleaker1** » Thu Jan 19, 2017 3:46 pm

Don't find 'em, grind 'em. , Hey, do you think those are made out of rubber? "He ground a pound". It's OK, that is a rock box". And last----------Drive much?".