4L60 (1990) End Play Problems
Does anyone have any ideas where I may have gone wrong? Thanks for any suggestions/help.

Last edited by Paxun; Feb 23, 2016 at 06:44 AM.
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.
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.
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.
Last edited by Paxun; Feb 23, 2016 at 09:35 AM.
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?
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.
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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.
Yeah, I would like to be a little tighter than .036. So, I might add 3 shims to put me at .018.
Last edited by Paxun; Feb 24, 2016 at 07:26 AM.
I set mine up at .018-.022" total end play.
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.
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.
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...
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.








