Too much end play after rebuild

Rebelrouser · Sunday at 10:18 AM

rklewis1005 said:
Ok, so went through the Tom Hand book, rebuilt everything, took my time during reassembly, reviewed my disassembly pictures as I reassembled - paying special attention to thrust washers and anything that didn't look right (many other posts as I went along), and guess what - I have too much end play.

When I measure pulling the input shaft back and forth it's ~ .099. When I measure flipping the transmission over (so the output shaft also moves a tad", it's .15.

I'm measuring endplay using calipers and a steel tube across the bell housing. Same tube each time, oriented the same way (sharpie) to ensure consistent measure point.

So what's the most obvious thing to look at as I disassemble it? It seems to me there is a lot of movent in the clutch packs s as I can see the part inside move (pic). I have a 3 thrust washers left over (pic) and they are all ~ .062 thick. I replaced all but the one under the sun gear snap ring (the book didn't seem to rebuild the sun gear) - but maybe I missed it.

We're headed out camping today so won't disassemble until Sunday afternoon.

Are there thicker thrust washers I should use? Any part numbers/urls to buy thicker ones are appreciated. They all seemed to match the original thicknesses and end play on input shaft was ~ .063 before rebuild.

I have all original thrust washers as I was doing 1 for 1 replacements.

Any thoughts on typical screw ups is appreciated.

Ross

View attachment 1926856

View attachment 1926857

Just to ask, are you taking the endplay measurements with the rear output housing on or off? If the output housing and the output bearing is not snapped into the rear snap ring in the housing you will get big endplay numbers like that.

rklewis1005 · Sunday at 12:12 PM

Rebelrouser said:
Just to ask, are you taking the endplay measurements with the rear output housing on or off? If the output housing and the output bearing is not snapped into the rear snap ring in the housing you will get big endplay numbers like that.

I have not put the extension housing on yet. I'll try that first - it may lower the total endplay, but wouldn't expect it to have much of an effect on the input shaft end play.

oldkimmer · Sunday at 4:17 PM

Also u need the output shaft on the floor or against the wall to check end play correctly not floating in the air. Kim

dvw · Sunday at 9:33 PM

Tail housing must be installed to measure endplay. Output shaht must be pushed all the way forward. Best if it is resting on the ground. The 3 tab "Mickey Mouse" #3 thrust washer is used with a 1990 and up input shafts. Looking at the back of the input shaft it will be very evident if it needs a 3 tab #3 washer. Just because the trans is a 69-70 doesn't mean parts haven't been swapped. So it could have anything. This stuff is old. There are all kinds of mix and matched parts. That can be a problem when building stuff If you are not knowlegeable of what the stock stuff looks like. Can make it easy to get into trouble. I also agree with post #5 on the 2 tab washer. That looks like a over drive 518 rear drum washer.
Doug

Geoff 2 · Monday at 12:10 AM

Why does the tail housing have too be installed for endplay measurement?

Rebelrouser · Monday at 7:00 AM

Geoff 2 said:
Why does the tail housing have too be installed for endplay measurement?

because the ball bearing that supports the output shaft is snap ringed into the housing, holding the output shaft in place. There is a thrust washer on the end of the output shaft that the drum sits against when you stack them. If the output shaft is not held in place your endplay of everything in front of it will be excessive.

dvw · Monday at 1:18 PM

End play is overrated. There will always be slop where the snap ring/ bearing assy seats So what you actually meassure is minimum with the bearing in the furthest forward posistion.
Doug

Geoff 2 · 2025-10-07T00:35:47-0500

Thanks. Got it.

rklewis1005 · 2025-10-07T09:23:03-0500

Ok, today's update. I installed the extension housing and it's much better. I measure the movement (endplay) of the input shaft 2 different ways.

1. I set the entire assembly on the floor - output shaft. In this position, I wasn't able to move the input shaft back and forth much at all and measure ~ .032

2. With the assembly attached to my engine stand, I flipped the case upside down - measuring both ways. When the bell housing was facing the floor I could reach under and move the input shaft in & out slightly. When I measure endplay that way it was ~ .061

As I had many thoughts/ideas/etc in this thread, I went ahead and disassembled the front half of the transmission back to the Sungear (pics). I took the sungear apart and measured the race. I don't see anywhere to buy a new race, but that's the only part that wasn't replaced/rebuilt. Does that race get replaced or just replace the whole sungear (I don't think it needs to be replaced). If someone knows what the correct thickness of that race should be so I can check, or where to buy a new one, please let me know.

Pictures of the disassembly and measurements of the various thrust washers are in the below sequence (tried to keep them in order). I had to break it into 2 replies to get all 20 pics.

Unless someone says that my end play numbers are bad, or that the sungear race should be replaced (and where to buy), I'm likely to reassemble and call it good.

rklewis1005 · 2025-10-07T09:23:41-0500

2nd half of pics.

Dave6T4 · 2025-10-07T09:48:12-0500

As I said before, if the rear stack went together with about .010" clearance at the snap ring, everything is O.K. That did not need to come apart again. Some people were questioning whether all the clutch plates were seated properly; if only 1 plate was not properly in place, you would not have any end play, and could not turn input shaft with pump assembly bolted in. I have rebuilt many 727's, and have rarely actually measured endplay. I am only concerned with whether I can get some back and forth input shaft movement with the pump bolted in place. If there actually is excessive endplay, it can be reduced by replacing the .086" phenolic washer at the rear of the pump assembly with a .100" nylon one.

rklewis1005 · 2025-10-07T10:19:59-0500

Dave6T4 said:
As I said before, if the rear stack went together with about .010" clearance at the snap ring, everything is O.K. That did not need to come apart again. Some people were questioning whether all the clutch plates were seated properly; if only 1 plate was not properly in place, you would not have any end play, and could not turn input shaft with pump assembly bolted in. I have rebuilt many 727's, and have rarely actually measured endplay. I am only concerned with whether I can get some back and forth input shaft movement with the pump bolted in place. If there actually is excessive endplay, it can be reduced by replacing the .086" phenolic washer at the rear of the pump assembly with a .100" nylon one.

Thanks - just had to confirm for myself that I didn't miss anything. It's the only way my brain would let it go.

dvw · 2025-10-07T12:28:27-0500

Never replaced a sun shell washer, ever. Your step #1 is the proper method for checking endplay.
Doug

rklewis1005 · 2025-10-07T12:35:16-0500

dvw said:
Never replaced a sun shell washer, ever. Your step #1 is the proper method for checking endplay.
Doug

Thanks - it's hard to get a good grip on the input shaft in that position and pull it out. It moves easier in the upside down position

Too much end play after rebuild

Rebelrouser

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oldkimmer

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dvw

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Geoff 2

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dvw

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rklewis1005

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