Gearbox counter shaft thrust washer.

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tomo256
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Gearbox counter shaft thrust washer.

#1

Post by tomo256 » Wed Jan 08, 2020 3:43 pm

Hi Guys.
Hopefully you can offer me some advise, just replaced the main shaft in my 4 speed gearbox and whilst replacing the counter shaft gear cluster noticed the end play was a little more than prescribed. All said and done I need a slightly thicker thrust washer between the casing and the cluster than I can find available, after doing the maths I need a washer of 0.125". Does anyone know of a source where they may be available, alternately can I install 2 together after surface grinding standard ones to thickness. I know I could rebush the casing but it is looking o.k. I know J.W. Boon does some under size that will fit exactly if i use 2 together, but he has a minimum order of around 50euro.
Thanks
Martin



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Re: Gearbox counter shaft thrust washer.

#2

Post by RUBONE » Wed Jan 08, 2020 4:43 pm

Generally when the largest available size does not work it is due to wear on the countershaft bushing (pressed in) on the right side of the case due to the washer spinning with the cluster and wearing it down.

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Re: Gearbox counter shaft thrust washer.

#3

Post by RooDog » Wed Jan 08, 2020 4:59 pm

Also, because the flange on the case bushing is considerable smaller in diameter than the thrust washer, the washer will tend to dish out, wear a groove on one side to match the profile of the case bushing. Another design flaw from the MoCo. Personally, I had a machinist buddy of mine make me a new bushing with the thrust flange the same, it could be larger, diameter as the thrust washer. This seems to have greatly reduced, if not eliminated, the wear upon the thrust washer. Sorry, I do not have any pictures as said parts are installed in my tranny. I did this mod back in 1975 and have not had occasion to go back into that tranny since then.
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Re: Gearbox counter shaft thrust washer.

#4

Post by tomo256 » Wed Jan 08, 2020 5:08 pm

Hi Rubone.
Thanks for the quick response, yes, I know I should maybe replace the case bushing but they do seem fine at the moment. J.W. Boon actually do a thrust washer 0.115” so oversize is available, just not the size I require. The gearbox was running great, just had a damaged key way and I thought better replace it.
Martin

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Re: Gearbox counter shaft thrust washer.

#5

Post by tomo256 » Wed Jan 08, 2020 5:45 pm

RooDog.
Yes seems like a good fix, just a step too far for me at the moment. I was looking for a simple fix at a reasonable cost. There is still plenty of meat left on the bushing and the box was working perfectly well before the strip down.
Martin

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Re: Gearbox counter shaft thrust washer.

#6

Post by 1950Panhead » Wed Jan 08, 2020 8:07 pm

Clearance over .100" means bushing is worn out.
The bushing and thrust washer are hardened, but only so deep, replace the bushing.

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Re: Gearbox counter shaft thrust washer.

#7

Post by RooDog » Wed Jan 08, 2020 9:20 pm

Sure, if you got that gear box torn down this far, and you're not going anywhere this weekend, then go ahead and replace the bushing and buy a set of thrust washers and select fit the one you need. They're cheap compared to paying someone else to work on your stuff, and you'll know for sure what has been done....
....RooDog....
PS: If it were me doing this job for my self, I would have a wide flange bushing made again like I did 45 years ago, but then, I'm running only 5 speeders now, even in my '68 FL....

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Re: Gearbox counter shaft thrust washer.

#8

Post by tomo256 » Thu Jan 09, 2020 2:29 pm

O.K. guys, really appreciate the replies and advise, don't know if I have been convinced or beaten into submission, but I am going to replace the bushes in the box. Next question. I have access to a press and am happy to remove and replace the bushes myself. Do the bushes require any reaming or not ?
If so surely the bush on the kicker side will have to be reamed before fitting ?
Martin

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Re: Gearbox counter shaft thrust washer.

#9

Post by 1950Panhead » Thu Jan 09, 2020 2:51 pm

If so surely the bush on the kicker side will have to be reamed before fitting ?
No machining needed.

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Re: Gearbox counter shaft thrust washer.

#10

Post by RUBONE » Thu Jan 09, 2020 3:12 pm

The bushings merely locate the countershaft in the case. There is no movement between them and no fitting is necessary, just warm up the case, tap one out, tap the other in, done.

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Re: Gearbox counter shaft thrust washer.

#11

Post by tomo256 » Sat Jan 11, 2020 11:50 am

Thanks again guys, new bushes ordered, everything in the U.K. has to be mail ordered. Managed to push the old ones out using a G cramp and some suitable sockets after warming the case a little.
Martin

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