Need advice on changing a transmission tail housing bushing

[Tom P.]

Re: Need advice on changing a transmission tail housing bushing

And yep, that method WILL work. A little crude backyard type method, but it definitely will work.
I personally have not used any of these methods for many years because when a bushing/rear seal had needed to be replaced, I've had the tranny out and dissassembled, so I just use the tool which drives out the old seal and drives in the new seal.
It's been so long since I last used the tool which pulls the bushing out while in the car that I can't remember when it was.

[Joe L.]

Re: Need advice on changing a transmission tail housing bushing

Here's some more dimensional information.

The output shaft is nominally 1 1/8" with 27 splines and the 6260048 bushing ID is 1.505", That leaves a radial clearance of about 3/16" inch, so the tool needs to be no more than 1.5" OD at the "hook" end when retracted and 1 1/8" ID. I don't see how the spline count would make any difference, and I would expect that other transmissions that use the 6260048 bushing also have the same output shaft OD.



It looks like the set in the first link that Gary C posted has three different size tools.

So, Tom, is does the tool you have conform to the above dimensions?

Duke

Duke------


The GM #6260048 bushing is the same one used for all 57-70 Corvettes with 4 speed transmission as well as all 1955-69 with 3 speed transmission, all 1955-67 Powerglides, and all 1975-82 with THM-350 or 700R.

[Duke W.]

Re: Need advice on changing a transmission tail housing bushing

Thanks very much to all for helping out. I'll be contacting Tom about borrowing his tool.

It's interesting that the T-50 has the same input and output shaft size/spline count as many vintage transmissions used on V-8s. The last version of the T-50 has a 205 lb-ft max input torque rating with a maximum input speed of 8500 revs. My earlier version is somewhat less on both.

But the T-50 is known to be somewhat delicate. It definitely doesn't like drag racing type shifts, but it never gave me a problem with roadracing shifts, which are somewhat slower and more deliberate, at least with the warranty replacement transmission that is currentlyl in my Cosworth Vega.

The original seized up at 7000 miles while I was driving northbound on the San Diego freeway just before my exit at Artesia Blvd in the city of Torrance. I was in the left lane and needed to move three lanes over to the right lane. Traffic was clear, and I began the yaw. About halfway into the no. 2 lane the car suddently slowed as if the brake was applied, then the axle started hopping. I intuitively understood what was happening and steered more to the right, but the car when into oversteer. I finally came to a stop on the shoulder at about a 45 degree angle to the road, with the left rear just barely out of the traffic lane.

Probably about half of the 700 or so '76 Cosworth Vegas built with T-50s seized up, and it was usually within the first few thousand miles, though I have heard of original T-50s seizing up at 40K. The problem was that first gear would seize to the mainshaft, which means two gears are engaged, and when that happens the whole thing locks. up. It was only a problem on the high revving Cosworths, not on the low revving four, V-6, and small V-8 engines.

I was so infuriated with GM's initial response to my problem (later resolved) that I wrote the newly formed NHTSA a letter about it, but never got the courtesy of a response. Nowadays there would definitely be a recall if not a national news story.

I was concerned the first few years I tracked the car that the replacment T-50 might do the same thing, but after a few years, a dozen track events, and a another 20K miles, I stopped worrying about it, and the replacement T-50 has functioned perfectly until the recently diagnosed worm tail housing bushing.

The T-50 is full of uncaged needle bearings and I dread the day that I have to overhaul it, but I think it will hold until the next owner buys it from my estate.

Duke

[Tom P.]

Re: Need advice on changing a transmission tail housing bushing

Duke,
My 76 Cutlass, which I ordered new, and still have, came with that 5sp and the small V8. After going through 3 of them, I built a healthy 455 Olds engine and installed a Richmond 5sp behind it. That was back in 88. Several months ago, I pulled the 455 and rebuilt it to a 468/W30 specs with Edlebrock heads/intake. Haven't touched the Richmond since installing it in 88.
My point? Those early 5spds were basically junk.

[Duke W.]

Re: Need advice on changing a transmission tail housing bushing

Yeah, there were actually three versions of the T-50: wide ratio (3.41, 2.08, 1.40, 1.00, 0.80:1), close ratio (3.10, 1.89, 1.25, 1.00, 0.84:1), and then there is what I refer to as the heavy duty wide ratio. This one was available on the Olds 260 gas and diesel V-8s, and by the last year of T-50 availability, 1979, it was the only version in production. It was improved over all earlier versions and the ratios are 3.40, 2.08, 1.39, 1.00, 0.80:1 . Internal improvements include different tooth counts, but AFAIK, first gear still was steel on steel and did not use a bushing on the ID of the gear to mate with the mainshaft.

The high revving CV engine which causes very high relative velocity between first gear and the mainshaft is why they seized up on CVs. The should have used a bronze bushing, like on M-22s.

Given my paranoia over the T-50, I located and bought a '79 version about 15 years ago, the last as described above, and keep it as a spare.

The CV doesn't approach the torque input limitation, but it does approach the input RPM limit.

At one point I considered installing a close ratio version with a 4.56:1 axle ratio. That would have provided better high speed accleration on the track, but would have been too buzzy for road trips, so I decided against it.

Now, I just take the CV to cruise nights and use it occasionally for errands and local trips. (It's VERY fun to drive and VERY RARE), but once in a while I like to buzz it to 7000 revs through at least the first three gears when opportunties arise.

Most guys think the T-50 is a PoS, and I tend to agree, but it does have well spaced ratios for a torque-shy high revving 2-liter four, and the replacement T-50 in my CV survived 5000 miles of race track hot-lapping without a major issue, so with a new tail housing bushing and seal it expect it will continue to serve me well with my more moderate driving schedule.

Here's another piece of trivia that came from my extensive T-50 research. As originally planned, it was to have a direct drive fifth gear. But the Japanese manufacturers were hyping "overdrive five-speed" in those post-first-gas-crisis years, so the design was changed to a direct drive fourth and overdrive fifth.

A direct drive top gear is best for fuel economy because overall efficiency is 98-99 percent in direct drive, but drops to 95-96 percent when the power has to go through the countershaft. BTW, the Richmond direct drive five-speed is certainly an excellent box. It's got high torque capacity, excellent ratio spreads, and will accept a lot of abusive shifting.

Duke

[Richard M.]

Re: Need advice on changing a transmission tail housing bushing

Duke, I have a O.E.M. Products P/N 2030 Rear Transmission Bushing Extractor you are welcome to borrow, I also have the matching Bushing Driver P/N 2040 if
you need it.

Richard Mynatt

[Steven B.]

Re: Need advice on changing a transmission tail housing bushing

If it is decided to collapse the bushing, you might want to try a cape chisel as opposed to a screwdriver. It can be used anywhere on the diameter of the bushing. I have removed bushings successfully with this method. The cape chisel will tend to leave the boss with little to no scarring. I would also be inclined to try to remove the bushing from the output shaft housing as opposed to leaving it in the transmission. IMO the puller would be the premium way to extract the bushing.

Steve

[William F.]

Re: Need advice on changing a transmission tail housing bushing

Stephen,
What's a cape chisel? Any pic?
Thanks

[Steven B.]

Re: Need advice on changing a transmission tail housing bushing

William,

Cape chisels are basically a half round with the end ground at an angle. The pictures here are of an older one that I ground lightly to clean up the end just a bit after years of use. This one has seen some automatic transmissions which are heavily bushed. You can Google cape chisel images, and get quite a wide variety of examples. This is the first time I've inserted an image. I hope it comes through OK.

Steve


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[Russ C.]

Re: Need advice on changing a transmission tail housing bushing

If it is decided to collapse the bushing, you might want to try a cape chisel as opposed to a screwdriver. It can be used anywhere on the diameter of the bushing. I have removed bushings successfully with this method. The cape chisel will tend to leave the boss with little to no scarring. I would also be inclined to try to remove the bushing from the output shaft housing as opposed to leaving it in the transmission. IMO the puller would be the premium way to extract the bushing.

Steve

Good suggestion Steven. But this is why you need to collapse the bushing from the oil drain hole in the tailshaft housing. NEVER try this method unless there is a similar oil drain slot to work from or you'll likely damage the housing regardless of the tool used.
Actually I built my own wedge tool, which is shown in the photo I posted. it's the (red) 3/8" piece of round stock with a wedge welded on the end, laying near the tailshaft. The bushing collapses very easily, which is why I mentioned that a screwdriver would work also.
For a bushing installer, I used two pieces of ex tubing that slip closely together and formed a shoulder to match the bushing inner diameter.
I'm not a professional, so I have to actually use my head sometimes, when working under my shade tree.