Do I Need A Transmission Rebuild?

I have a 1970 CJ5 with Dauntless V6, T-14 transmission and Dana 18 T-Case.

Shifting from 1st to 2nd is smooth.

Shifting from 2nd to 3rd at 20-25 mph (or higher) will grind a little unless I hold the clutch in to give it some time.

Downshifting from 3rd to 2nd is smooth as silk at 30 mph or less.

Downshifting from 2nd to 1st must be done by either double clutching or slowing down to 1 or 2 MPH.

I have fresh fluid in transmission and t-case.

Is this normal or am I experiencing symptoms of transmission issues requiring a rebuild?

 

I can't speak as to whether it's pointing towards a rebuild, but I can say that the T14, I took out of mine, when swapping to the T98, didn't exhibit those symptoms, other than a *little* grinding on the 1-2 upshift, if I was really on the throttle.

 

There are blocking rings in the transmission that wear out. They only act going into a gear. They are basically conical clutches that force gear speeds to match when you shift. Most drivers would downshift to first very seldom... you really don't need first except from a standing stop. Second typically wears out first, because it's the most useful downshift. Third gets little wear because there's not much speed difference between the gears.

Note that these are blocking rings, and the more speed difference between the gears, the more blocking action you should feel. If the gear speeds are lined up, it should slide in smoothly.

How fast the blocking rings wear out depends a lot on the driver, and how much use is made of the blocking rings. I suggest you focus on driving so the gears don't clash. Early cars did not have synchromesh - drivers were expected to match gear speeds, and they did. If you pick the right speed for your upshifts, you won't even need the clutch.

There could be something else wrong, besides "normal" wear, that causes gear clash. That you have grinding going into 3rd is suspicious. That's not usual.

 

Thanks for the info!

I’m not sure how the Jeep was driven before I bought it. Or even how well it was maintained. Probably not very well I’m guessing.

Any thoughts on what to look for regarding the grinding going into 3rd?

 

I can only guess. You really can't do anything to a manual transmission other than change the oil without removing it and taking it apart. The blocking rings and the front main bearing seem to be the most wear-prone parts. If the input shaft were misaligned with the main shaft, that might grind going into 3rd. I'd look at the front main bearing, the input shaft pocket bearing, the pilot bushing, the 2-3 synchro hub. Just guessing.

 

Thank you!

 

Make sure your clutch is adjusted correctly. Check pedal free play and if it is more than about an inch the clutch may not be disengaging soon enough.

 

I measured the play and there’s almost an inch before the cable starts to engage.

How do I adjust this? Is this even correct?

 

There should be a threaded end on the cable, at the clutch fork, with a couple of jam nuts, for adjusting it.

 

Thanks. I’ll give that a shot.

Hoping the path of least resistance will work before diving into the suggestions timgr provided.

Thanks again for the help!

 

Your clutch just needs adjustment.

 

If it were just the clutch out of adjustment, the synchros would prevent it from going into gear unless the RPMs matched, or even grinding.
My guess is either the trans needs a rebuild, or it’s dangerously low on oil.

 

I’m afraid I can confirm the oil in both the transfer case and transmission is full.

When I take the fill plug out of both tcase and transmission I can feel oil with my finger.

I’m afraid to ask how much a rebuild might cost. Any idea what to expect?

 

Assuming you don't need any gears, I want to say I remember Novak doing a "Master Kit" for like $300-$350-ish Assuming you do the work yourself.

You can check their website easily enough.

Yeah, I just looked, and my memory is faulty. $165-ish. But they're on f*&king indefinite backorder, like just about everything else lately.

 

It’s actually not leaking (too bad). Ive rebuilt my 2g carb, re stuck my distributor, and learned how to install and adjust points. Just simple stuff.

But I’ve never done anything like rebuilding a trans before. Not sure I even have the right tools to do that.

 

My '70 cj5 had the same shifting problem you describe, except it happened shifting between 2nd and 3rd. I ordered a Novak rebuild kit. As others have mentioned, the synchronizers made of brass, had worn out.


I removed the transmission/transfer case in my garage and rebuilt it myself. I've never opened a transmission before, but the Novak instructions were good. It probably took me a month working on it here and there to go from removing the transmission, rebuilding it, and reinstalling it. The removing it and reinstalling it was not too fun, but rebuilding the transmission was fun. You can do it! Isn't there a member here on ecj5 who can remove and install a transmission in under an hour?

 

At least try adjusting the clutch before you dive into a rebuild of the transmission. Just tighten it a little and see if that helps.