C6 End Play Problem

C6 End Play Problem

Joined: July 2nd, 2006, 7:38 pm

May 26th, 2012, 3:33 pm #1

My 1971 F100 2WD C6 looked to be in good condition when I bought it from a wrecking yard. I checked the end play with a dial indicator on the input shaft before disassembly and it had about .030 end play. I went through the transmission completely installing new gaskets, seals, clutch disks, steels and thrust washers. I did not change the two torrington bearings as they looked perfect. I soaked the disks and the bands in ATF as directed. All went well in disassembly and reassembly. I have two shop manuals and the Ken's CD set (by the way, they are great!). Anyway, my problem is that I don't have enough end play with the new parts installed. With the pump bolts torqued I have zero. I disassembled and reassembled the transmission 3-4 times and I am sure I have everything together correctly. Just to see, I removed the pump thrust washer and with the washer removed, I have about .025 end play. Again, I checked this with a dial indicator on the input shaft and reverified it with feeler gauges. The original thrust washer I removed was .080 thick. Should I leave the pump thrust washer out? Am I missing something? Thanks!
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Joined: January 21st, 2005, 3:11 am

May 26th, 2012, 3:58 pm #2

Hi Phil, there's no question something is out of place. You don't have the tranny standing on it's end with the output shaft resting on the floor? One area you what to take a look, the needle thrust washer between the forward planet and clutch drum. Be sure it's not backwards. You will see it only fits correctly in the drum one way. Be sure the direct clutch is all the way down on the forward clutch and build the drums and sun gear shell as in the video checking the shell/direct drum lug contact. Give it another look, you'll find the problem.

Ken Collins, BadShoe Productions, How To DVD's specializing in Ford drivetrains www.badshoeproductions.com (banner ad below)
email; badshoe@myway.com
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Joined: July 2nd, 2006, 7:38 pm

May 26th, 2012, 7:05 pm #3

I dissassembled the transmission 3 more times and checked everything over and over. I'm getting to be an expert at this. My two needle thrust washers are the three piece design. The one on the bottom of the forward planet has the shell pointing in the right direction. The one on the top of the planet is not removeable as the gears are in the way. The flat thrust washers are all installed correctly. I took the drums back apart and everything meshes perfectly with no bent or broken parts. The ears on the sun gear shell are well down into the slots. I even took out the one way clutch again and found nothing. I checked the rear clutch with air and it works. The old selective thrust washer behind the pump is .078". All is fine until the pump is near seated. At that point the end play goes to zero. I really think what I need is a thinner selective thrust washer. I'm surprised it wasn't in the washer kit I bought? I did notice there is a thinner black plastic thrust washer in the kit with a single tab like my original pump thrust washer. What size selective thrust washers are available?
Last edited by flawebmaster on May 26th, 2012, 7:27 pm, edited 1 time in total.
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Joined: January 21st, 2005, 3:11 am

May 27th, 2012, 2:26 am #4

I think you said the end play was .025" with no #1 washer installed correct? There's .060" #1 washer available (maybe that's the black washer you spoke of) but that's not going to help here. Something isn't installed right. The unit had good end play before disassembly. Did you change the #9 washer to a needle bearing? A needle bearing can't be used there unless a thinner one-way race is installed. As long as the output shaft snap ring installed ok, the parts in the one-way clutch area should be correct. Did you turn the reverse drum clockwise while pushing in? Sometimes when the rear planet to drum snap ring is installed the drum has to be pulled out a little. Therefore it must be pushed back in and might need to turn the drum to seat it back. You say you have a three piece bearing on the forward planet. Is the large race in the forward drum set so the outer lip faces up, then the needle bearing and then the other smaller race has the inner lip facing up toward the planet so the lip fits in the planet nose?

Ken Collins, BadShoe Productions, How To DVD's specializing in Ford drivetrains www.badshoeproductions.com (banner ad below)
email; badshoe@myway.com
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Gregaust
Gregaust

May 27th, 2012, 8:59 am #5

If all you changed was clutches eyc as a basic rebuild something is out of whack somewhere there . You didn't change anything that would alter the endfloat that far ?? I know you've checked but something is going wrong here . I've done plenty and usually if the endfloat was ok to start with after reassembly is back to where it started .
What gasket is used on the pump? Thinner than original?

You are assembling the fwd and high drums and front planets, input shell etc as a unit pn the bench then fitting into the case?
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Joined: July 2nd, 2006, 7:38 pm

May 27th, 2012, 11:55 am #6

I removed the metal pump thrust washer and replaced it with the thinner black plastic washer in the kit. It definitely helped. With the pump bolts tight, the front and rear shafts turn free with a rag. There is still no discernable end play, but the transmission doesn't lock up. I think this means that I'm only .010 or so from spec.

My transmission has a bolt-on yoke, so there is no snap ring. I always install the "fwd and high drums and front planets, input shell, etc" as a unit with the tail housing bolted on to hold the output shaft in position by the large tail shaft bearing. I am positive all of the clutches are properly engaged. There is a gasket under the pump and it is the same thickness as the original. I have not changed any of the thrust washers to needle bearings. The needle bearing races are in the correct position.

I've thought about this and the only way this could happen is that one or more of the thrust washers I changed must be thicker than the original. All the washers that were in my transmission when I bought it were in perfect shape except for one. I pulled out the one that looked worn this morning and most of the copper metal was worn off, but it had not worn down much into the washer itself. The only thing I can do at this point is to pull the transmission back apart and check every washer. This is a hobby project, so I'm not too concerned about it. It's frustrating because I know I have the darn thing back together right.
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Joined: May 23rd, 2004, 6:30 pm

May 27th, 2012, 8:10 pm #7

you need to check the torrington pocket depth in the forward drum against the stack hieght of the front ringgear hieght old style is .330" new style after mid '76 is .400 ,you may have the wrong ringgear
Frank
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Joined: July 2nd, 2006, 7:38 pm

May 27th, 2012, 8:23 pm #8

I removed the metal pump thrust washer and replaced it with the thinner black plastic washer in the kit. It definitely helped. With the pump bolts tight, the front and rear shafts turn free with a rag. There is still no discernable end play, but the transmission doesn't lock up. I think this means that I'm only .010 or so from spec.

My transmission has a bolt-on yoke, so there is no snap ring. I always install the "fwd and high drums and front planets, input shell, etc" as a unit with the tail housing bolted on to hold the output shaft in position by the large tail shaft bearing. I am positive all of the clutches are properly engaged. There is a gasket under the pump and it is the same thickness as the original. I have not changed any of the thrust washers to needle bearings. The needle bearing races are in the correct position.

I've thought about this and the only way this could happen is that one or more of the thrust washers I changed must be thicker than the original. All the washers that were in my transmission when I bought it were in perfect shape except for one. I pulled out the one that looked worn this morning and most of the copper metal was worn off, but it had not worn down much into the washer itself. The only thing I can do at this point is to pull the transmission back apart and check every washer. This is a hobby project, so I'm not too concerned about it. It's frustrating because I know I have the darn thing back together right.
I pulled the tranny apart again and checked all the thrust washers. Every one of them is .060" thick and perfect. I assume the reason all the thrust washer tang patterns are different is so that you can't mix them up. The only one I had any question about was #8 on the back of the rear planetary. The tangs on that washer don't fit into the round holes in the planetary (2 do and 2 fit into the long slots in the aluminum planetary frame itself). With that said, #8 thrust washer sits perfectly flat between the rear planetary and the one way clutch race. The bottom needle bearing shell(open three piece design) is in perfect position with the bottom half (round end down) pointing up. The needle bearing itself sits in the bottom shell and the top half points up where it fits into the bottom of the planetary. The upper needle bearing shell and the bearing itself is sitting in the top of the rear planetary and has never been removed. The top shell of that bearing is facing up where it contacts the sun gear when everything is assembled.

All the clutch hubs are in position and perfectly seated into the clutch disks. The tabs of the reverse-high clutch fit down into the input shell slots with about 1/8 on either side of the tab.

With the pump bolts tight but not torqued and the thin black plastic selective washer behind the pump, everything turns and feels fine. I cannot detect any free play with a feeler gauge or my dial indicator.

So, what does this all mean? I had .30 end-play to start with (dial indicator and feeler gauge). My original selective pump washer was .078 thick and the plastic one is about .058. At this point, I have no end play. This means I've gained about .050" somewhere. There's nothing spongy and after 10 or so tries I can't see anything wrong or out of place. Is it possible the one way clutch race is not seated in the case? I took it out twice and made sure the oil feed hole was aligned correctly. The bolts holding it in torque down without incident. I thought I might have added an additional thrust washer, but I don't see where that's possible.

I'm totally stumped...
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Joined: July 2nd, 2006, 7:38 pm

May 27th, 2012, 9:04 pm #9

I watched the video again and can see that my rear planetary is a four gear design (truck). This may explain why 2 of the thrust washer tangs on the rear thrust washer don't go into round holes. Both washers front and back fit flush against the planetary. Are there any differences here that could be causing my problem? Thanks!
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Joined: May 23rd, 2004, 6:30 pm

May 27th, 2012, 11:43 pm #10

there are different thrust washers for a 4pinion planetary compared to a 3pinion
Frank
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