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I'm working my way thru the drivetrane on my 1969 4spd bb. my transmission yoke is pretty badly worn. Can anyone recommend a reasonable source to get a replacement? Also is it difficult to replace the rear seal and bushing on the Muncie transission? Thanks, Bill
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Re: transmission yoke...
The seal in the muncie is easy to do, I just collaspe the old one with a screwdriver then install the new one. The bushing is a little more difficult, you don't mention if the trans is in or out of the car. It is much easier to remove the bushing with the rear housing off the trans. I have never tried to do one in the car.
The yoke is availble from any good driveline shop, they can replace it and service the u-joints cheaper than you can buy the parts. -
Re: transmission yoke...
Wally, The transmission is in the car, how difficult is it to remove the tail section of the muncie? The driveline shop that I deal with wasn't able to get a replacement yoke, he has a used one that is 1/2 and inch longer than the one that was in my car. Thanks, BillComment
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Re: transmission yoke...
Bill-----
The transmission rear yoke for your application, GM #3868728, is still available from GM. That's the good news. The bad news is that it carries a current GM list price of $176.00. You should, however, be able to buy this from competitive dealers for at least 25% off that price or about $130. You might also try driveline shops that sell/service driveshafts and universal joints. IF THEY HAVE IT, you can usually get very good prices. However, this particular yoke is primarily a Corvette-only piece, so I doubt that you'll find one. Also, I believe that Spicer has discontinued it. But, it's worth a try to a few driveline shops. Give them the GM number that I provided and they should be able to cross reference it.
As far as the seal and extension bushing goes, I've got more good news and bad news for you. The seal is easily replaced. It is currently GM #8673526 and GM lists for $9.88. Simply carefully pry out the old one and install the new one.
Unfortunately, the bushing is not so easy to replace. To replace it, you really need to remove the transmission from the car and remove the extension housing. The bushing must then be pressed out of the housing and a new one pressed in. It is very easy to do with the transmission out of the car and the extension housing removed, but essentially impossible with the transmission in the car. And, especially if your present yoke is in bad shape, YOU MUST REPLACE THE BUSHING. If you don't, you'll likely destroy the new yoke in short order. The bushing is also still available from GM under part number 6260048. It carries a list price of $2.77.In Appreciation of John HinckleyComment
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Re: transmission yoke...
Bill, that rear housing would be very difficult or impossible to remove in the car. Like Joe said trans out its easy to do. I'm checking suppliers for the yoke in my area right now and will let you know what price I come up with.Comment
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Re: transmission yoke...While we're on the subject
Is there an accurate way of determining if your bushing is worn out while everything is still installed? I have always just grabbed the yoke and felt for radial play, but this has always seemed too subjective.
Is there an actual limit or other method?
NCRS Quebec ChapterComment
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Re: transmission yoke...
Shop here in Maryland has the yoke for $50 or $60, it depends on which joint it uses, how it is held in place. Yoke is made by Spicer.Comment
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Re: transmission yoke...While we're on the subject
The seal puts a fair amount of pressue on the yoke, I guess you could get a better feel for play if the seal were out. How much play is a good question, I don't know how much is to much.
The bushing will last damn near forever if the drive shaft and the u-joints are serviced and kept running true. Only when thinks get out of alignment or the u-joints fail will it take out the bushing. Notice I said normally.Comment
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Re: transmission yoke...While we're on the subject
It's funny you mentioned that "U-joints are serviced and running true" because I when I had the u-joints replaced, the shop checked the drive shaft for balance and found it was out of balance and had to add weights. The u-joints were OK but I had them replaced anyway just so that I have a starting point for myself. Thanks, BillComment
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Re: transmission yoke...While we're on the subject
Bill-----
As Wally mentioned, the bushing is USUALLY a long-lived piece. However, if there is wear on the outer surface of the yoke, which is usually the only reason that folks replace them, the bushing MUST BE REPLACED. This bushing is a steel-backed bushing overplated with babbit/tin/bronze. It is much softer than the yoke.
Incidentally, these bushings are very similar in construction to those used for the steering box Pitman shaft and the alternator slip ring end bushing.In Appreciation of John HinckleyComment
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Re: transmission yoke...While we're on the subject
Wally, Joe,
I spoke with my parts man at GM and he said he'd sell me the yoke at a pretty good discount. I think I'll take the transmission out also. Thanks for all the info and help.
BillComment
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Re: transmission yoke...While we're on the subject
IF he is not willing to sell it to you for sixty or less, by the Spicer yoke. The GM unit may be made by Spicer and marked up a load.
Good luck with the trans!Comment
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