end float - how much is too much

W

weemark

Senior Member
ive been looking at my '39 transmission, had an issue with 2nd gear jumping out, the trans was meant to be rebuilt from a well known shop in the USA...

Anyway I measured the gap between 2nd gear and the thrust washer and its 0.014" so I know this needs addressed. whilst I was there I noticed the main shaft moved back and forward in the case, I thought it might be the snap ring on the rear bearing but it seems pretty tight on the bearing and there is only 0.005" of a gap between the snap ring and the groove which doesn't seem excessive. The shaft moves back and forth about 2mm - is this excessive? if it is excessive what is the best way to help remove some of the play?
 
Recheck the mainshaft (output shaft) endplay after you have installed your universal joint and tightened down the bolt and washer. This has to be in place before you can determine if there are endplay issues. The rear bearing snap ring should be 0.075 to 0.077" thick. Don't reuse an old snap ring.
 
mac the figure ive quoted is the movement on the shaft with the UJ tightened down with the washer and bolt. Sorry I didn't measure the size of the snap ring on the bearing, will do that tomorrow and will post the size of it up.
 
Hi Mark. If the rear bearing retainer is on and bolted up, and the uj is on and bolted up, the shaft should be solidly located by the bearing inner. If you have 2mm end float, it means the bearing is moving 2mm.

If you really do have that amount of play it ought to be clearly visible what is moving to give the play.

Is the UJ tightening down properly? Thick washer in place and bolt not too long??

Have another look and report back.

Mart.
 
mart your right the bearing is moving 2mm. the retainer is on and bolted up, the UJ is as tight as it will go, thick washer in place and the bolt isn't too long, I tried a shorter bolt in its place just to make doubly sure. ive got a short video of it moving, will try and upload it shortly.

below is a video of whats happening, its like the shaft is too long and as such isn't getting clamped properly, the spacing between the UJ and the shaft is wrong.

Sorry cant embed the video to play on this site.

http://www.garagescene.co.uk/stuff/newvid.mp4

https://youtu.be/_VnpylGUFGU
 
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Ok, You need to investigate why the rear bearing is moving. Is the outer part moving 2mm also? You might need to make a shim to hold the bearing hard against the case. Some replacement bearings have a thinner circlip which can make for bearing movement. But not 2mm worth.

Mart.
 
Is the rear oil baffle in place on the mainshaft? It's located at the back end of the mainshaft, just in front of the rear ball bearing.
 
The rear bearing is held in place by the rear trans, mount . Most rear bearings the ring and bearing grove is thinner. Also the the rear mount gasket is too thick . Install mount without gasket and check endplay. You will need to either use no gasket and just use Sealer or make a spacer out of shim stock that goes on the back side of the bearing into the trans, mount or make your own gasket to get the correct end play.
 
mart the spring clip on the bearing is the correct ford part and is the correct size. yep the outer part is moving as well

mac yes the baffle is on, you can kind of see it in the video I just put up.

quickchange34 there is no gasket on it in the video I put up and it still has play in it.

I wondered if plate B-5099-A was too thick and was spacing the retainer away from the bearing too much? is this possible?
 
Just watched the clip. Blimey it really is moving. On mine I made a shim to keep the bearing loaded against the transmission.

In theory, you could be right about the plate. If you can, just try the bare housing on it's own and see if it makes a difference. the plate may have been hand made and could be too thick.

Mart.
 
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a question - when you put the UJ on and tighten the bolt what does it push against to tighten the shaft/bearing into the casing?
 
It don't. It just holds the shaft tight in the inner race of the bearing. The rear mount is what holds the bearing into the box. You have got the rear mount bolted up tight?? Yes??

Mart.
 
mart yes ive got the rear mount bolted tight.

Now ive just been out again, because this is bugging me, I removed the plate B-5099-A and bolted the retainer on and it doesn't bolt the bearing/shaft in tight, there is still a very small amount of backward and forward movement on the shaft which suggests the rear retainer might have too big a register cut into it to retain the bearing and snap ring? if I got the retainer machined down by the appropriate amount would that do the trick? or should I get a spacer made to fit in the retainer?

how much forward/backward movement should there be on the bearing?
 
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That sounds normal. Ideally the bearing can be shimmed to get the play down to zero. Remember to take into account gasket thicknesses etc. I wouldn't machine down the retainer to make the register shallower. You also need to address why there is more play when the rear mount plate is fitted.

Mart.
 
Please post a picture of your B-7085 rear bearing retainer......showing the side that faces the back of the transmission.....I have a suspicion.
 
I had a real problem with the trans in my 33,never jumped out of gear ,but would make a funny zish noise when on and off the gas more load = more noise,found about .040 end ply between the input and output shafts.the problem was ,when comparing the new bearing retainer rings to an old original one, was about .0012 thinner ,this at both front and rear bearings, my fix was to machine the front bearing retainer and rear mount/bearing retainer to get zero play in the retainer ring area,net result, noise gone .
This play is in the last three trans I have done.
Its a pain to fix ,but well worth the effort.
Lawrie
 
Mac VP said:
Please post a picture of your B-7085 rear bearing retainer......showing the side that faces the back of the transmission.....I have a suspicion.
Click to expand...

mac it will be tomorrow now because it is midnight here in the uk.
 
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here is the back of it, ive not cleaned it up since taking it off so there some gasket material on there, the paint is just a quick coat from a rattle can just to stop rust.

retainer.jpg
 
It seems that the thickness of the plate plus the depth of the register in the rear mount/bearing support is not allowing the support to do what it's there for - to support the bearing and hold its snap ring tight against the casing.

What is the combined plate thickness and register depth? How much more is that than the snap ring thickness?

If the plate is necessary to support the rubber of the rear mount then is there another rear mount without the register, ie. a flat surface?
 
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