Paxun

I have no end play at all when I install the pump. I did change out the old reverse input drum for the newer style and the piston. Everything appears to be back together fine. However, when I install the reverse input drum it sits down on the new bearing that I installed, which I can see clearly. However, when I drop this assembly into the trans something is causing the reverse input drum to not drop all the way into the trans (see photo) and the reverse input drum pushes up and away from the bearing about 3/8". I think this is causing the pump to smash into the reverse input drum resulting in no end play-with my level of expertise I could be completely wrong.

Does anyone have any ideas where I may have gone wrong? Thanks for any suggestions/help.

clinebarger

You likely don't have the 3-4's fully laced into the 3-4 clutch hub, Put the unit in park, Keeping turning the input shaft left & right 'till the input drum falls down away from the reverse input drum.

With everything seated, There will be slack between the 2 drums, Bolting the pump down without the 3-4's fully laced can bend the first 1, 2 or however many frictions didn't engage onto the hub.

mrvedit

Did you change anything related to the sun shell, reaction shaft carrier or the front planetary, especially the bearings?
I recall a post where the OP changed to a torrington bearing under a new reaction carrier, but also left the old-style thrust bearing in. I'm referring to part #669 in the diagrams.

Personally, in order to set the desired end play with the selective washer, I leave out the 3/4 clutch as the input drum is then trivial to install. For checking, you can also leave off the reverse drum as it does not affect the end play. Then install the pump with the bolts only slightly tightened, and measure the end play. Don't forget the pump-to-case gasket.
Remove the pump and input drum and install the 3/4 clutch. If necessary, change the selective washer to get the desired end play. Then perform the final assembly with the reverse drum and the plastic thrush washer.

As for end play, aim for the low side of .015. Personally, on a rebuild with new bearings I even aim for .010 as I find that it quickly increases a few thousands after just a few miles.

Good luck and keep us posted. I certainly would like to know what you find so that I can better help the next guy. Do any gals rebuild transmissions? Probably not, as they are too smart for that.

Paxun

Thanks for the suggestions guys. I will take a look at the 3/4 clutch plates and see if anything has happened here.

Question: The reverse input drum should rise up off of #621 (Input Housing Shaft Assembly) and away from #615 (Bearing Assembly) when installed into the case about 1/8"?

mrV: I only changed the roller bearings and bushings, that is all of the parts you mentioned. I am 99.99999% sure that I removed the old bearings before installing the new ones. However, I would hang my head in shame and admit to this mistake here if I had made it. I took new bearings out of the plastic bag, put the old one in the pack and mark with "old". I think I have #68 selective washer and the end play is gone before the pump seats back onto the gasket-I have observed this watching how close the pump is to the new pump-to-case gasket before end play becomes 0.000.

I did add the 3-4 Clutch boost spring assemblies (#600) that were removed by "Chester" the last re-builder. This was not the best transmission for a noob to be messing with.

I do recall the guy who rebuilt a few transmissions for me years ago had his daughter rebuilding for him. I almost took this transmission to him, but his daughter isn't working for him anymore and he is not easy on the eyes, so he lost my business.

Thanks again guys. Will let you know what I find out.

Paxun

Did some more digging:
1. #69 selective washer (number visible when installed) measured at .086" ;
2. bearing .132" thick black visible when installed atop of input drum;
3. .012" gasket thickness (installed for all measurements) 9pump o-ring removed);
4. removed reverse input drum, 3-4 clutches & steels no change; and
5. .037" end play when selective washer is removed (bearing installed).

From these numbers it appears I am .049" from having exactly no clearance. and if I add a minimum of .010 to that I am exactly .059" minimum from having the correct amount of clearance.

What might cause a .059"-.099" discrepancy to the main input shaft?

mrvedit

With the 3/4 clutch removed, it should be easy to test-assemble the input drum and pump to figure this out.
From a few similar posts, this sounds like a bearing problem to me - either wrong one or something is doubled up.
I assume the output shaft snap ring is fully seated.

Paxun

Bounced it gently on the tail-shaft a few times and few times on the case (tail through hole) trying to get it settle inside. It appears to have worked. End play is now .063" with a #69 measured at .086". So, I will try a #74 which should get me just within max tolerance of .036."

mrvedit

Glad you figured it out
Sorry I didn't think of bouncing the internals to make sure they were all pushed back/down.

Paxun

Know a good place to get #74? Not able to find one locally.

clinebarger

Sonnax has .015" shims you can install between your selective & the Drum, Part# 77409-15.

You can also bring up the entire Geartrian by shimming between the rear carrier support & case bearing, I prefer this method because it tightens up the endplay between the Stator Thrust & Reverse Input Drum along with total endplay, Sonnax Part# 77406-10.

mrvedit

If can't find them cheap, let me know and I will mail a few to you in an envelope.

bbond105

I’m a little confused Paxun. What is the target endplay that you are trying to reach? .036"???

Paxun

Thanks guys I found the shims cheap enough. Got them on order.

Yeah, I would like to be a little tighter than .036. So, I might add 3 shims to put me at .018.

bbond105

Yeah, I would shoot for the low side.

Dynamic396

There's something not quite right if, after changing the bearings, you have .068" end play with a #69 shim. The bearings can vary in thickness a little bit, but not that much. I think I'd do some more checking...

I set mine up at .018-.022" total end play.

mrvedit

Yeah, I missed that. If you didn't change any hard parts, the end play shouldn't change very much even with new bearings.

Too late now, but for any future DIYers reading this, it is good to measure the end play before opening the trans. That gives you some idea of the internal condition and something to compare to later.

Paxun

The trans is stamped "CJ" 1990, so it appears it was originally equipped for 2wd truck. Years later the tail shaft swapped and implanted into a 1988 GTA that was wrecked. I was looking for a core about two years ago and bought this one for $150 "working great when wrecked." It was a mess!

Pulled it for rebuild in December. The PO had changed things not in any rebuild text. Only an expert could explain what has been done here.The 5 3-4 boost springs were not present. Orange gasket sealer on the o-rings. Clutch plates ground off flat. 2 valves stuck - at least - with clutch material everywhere...! Old reverse input drum with new steel piston. Someone had been through this from top-to-bottom. Worst trans in the world for a noob.

I have changed the reverse input drum due to overheating, steel plates, all bushings, torque converter, gaskets, bearings, rubbers and all new pump components. Sure I am missing something here. Just trying to make a good transmission out of this. I agree though, I should not be this far off at this point, but it is far improved from where it came from.

Dynamic396

Sounds like they mis-matched a bunch of parts in there. The R/I drum with the steel piston is an early 700R4 drum. The later drums (aluminum piston) have quite a bit more piston surface area and a larger feed hole.

Leaving the load release springs out of the 3-4 is not a big deal. I leave them out on many builds, too.

Gasket sealer on o-rings...? Yeah, that's not good...

Paxun

Does anyone have some Sonnax shims they can check with calipers? I got mine yesterday and they are .009 thick on the two tested. Just curious....my calipers or the shims?

mrvedit

I just checked the shims I have and they are .015 each. I think they are from Sonnax, but the label is long gone.
Why do you care if they are .009 or .010 or even .015?
Use what you need to get the end play into the .010 to .035 range.
A local trans shop might have other selective washers and be willing to swap.