Slip yoke

I'm not exactly sure of the differences in the trannys but I know you need more the 1/4 inch play there As the suspension goes down it has to slip in to the tranny and when the truck is lifted it pulls out of the tranny so you need to put it about half way in with the weight of the truck on the suspension then measure the tube length to the rear end I would cut the tube for sure not the yoke If its to tight it will crunch something when suspension is compressed to loose and it will fall out when lifted.

I have resized over a dozen drive shafts my self cut the weld off carefully with grinder straight as you can get it its thin so don't go to deep tap it off then cut tube with chop saw the right size put the end back on making sure the end are straight to each other then with a square along the tube hanging over the end measure it straight tack it measure it again and weld or take to machine shop and the can do it much easer on lathe but I'm cheep, I do it my self. Good luck

Shortening the propshaft is the ideal solution (certainly much less headache than relocating the eng/trans).

Trimming the front of the slip yoke could get one in trouble: as the suspension is compressed, the slip yoke will ride forward on the trans' output. Although the leading edge will, subsequent to trimming, not strike the tailshaft, the yoke could bottom out on the mainshaft. The result would be a broken trans mount, bent trans mainshaft, bent driveshaft, damaged universal, etc.

Even if one verifies that this won't happen, the total engaged area of splined connection is reduced after trimming; it is therefore theoretically possible that the splines could rip out under heavy load.

Mark

If the yoke you have now has a sort of extension beyond the splined end you can swap it for a yoke that has not got the extension. When you look into the yoke if there are no splines for an inch or two then you maybe can do the swap. The extended yoke is typically found on the TH400 tranny but sometimes on other applications. The standard length yoke is used on 3 and

4 speed GM manual trannys from around 1966 and later and also the TH350.

As others have mentioned you have to be sure that the yoke has enough room to slip deeper into the tranny with suspension movement and not bottom against the speedo gear on the output shaft.

IIRC your problem comes from the location difference of the speedo gear on the output shaft from the T-10 and the Sag. Normally not a problem when swapping unless you have the long yoke.

I replaced a 4 speed tranny, Saginaw to T10, in my old Chevy 1/2 ton pick up truck. When I put the drive shaft back on I found that the yoke can't go as deep into the output spline in the T10 case as it did in the Saginaw. It bottoms out just short of where I need it to. The net result is I need less than a quarter inch taken off in back or the tranny or the same moved forward so I can fit the driveshaft on the rear end...sigh.

It seems like the easiest thing for me to do is to take off about 1/4 inch or so from the yoke. If I take it to a good machine shop, can they do this for me? The other solution I'm considering is to move the engine up just a bit. It's a retro fit 350 crate engine. Lot's space to move it is available. I only need less than a 1/4 inch.

Any thoughts on this would be appreciated.

JM

Thanks to all the responses!

The yoke I have has splines all the way to the end. The shaft is approx 3.5 inches. The yoke is 5.5 total. It fits about 3/4 into the output shaft. If I made the yoke shorter it could give me room to fit the driveshaft on and I would have the same yoke........Interesting point about the spedo gear. I'm going to take it out and see if I can fit the yoke on further. The spedometer fitting as I'll call it doesn't have gears in it. It's just a metal cylindar that bottoms out at the bottom of the case. Could it be the wrong type of spedometer fitting or something like that?

Anyway, great tip......I'll report back this weekend when I have time to crawl under the truck again. Actually, I'll make my teenage son do the crawling. :-)

John

John, removing the speedo driven gear and the cable adapter won't make any difference for what you are trying to figure out. The speedo DRIVE gear will still be on the transmissions tail shaft so the yoke will still bottom against it if that in fact is the actual problem. Try this first: measure along the outside of the tranny from the back of the speedo cable adapter to the end of the tranny tailshaft. If it measures at least as long as the yoke from where you see the seal has been rubbing to the front open end of the yoke then the speedo gear is not your problem. From your dimensions the yoke sounds like the standard length one. Don't cut it. If you have the old tranny still around measure it from the bellhousing mounting face to the end of the tailshaft and compare the measurement to the new tranny. If the new tranny is longer than the old one the best thing is have the driveshaft shortened by the amount of difference in the length of the 2 trannys. Have it done at a professional driveshaft shop. It is worth the time and money. Around here the d-shaft shops charge @ $55 for one cut / reweld and a rebalance. Any needed u-joints, etc of course are additional.

The yoke I have has splines all the way to the end. The shaft is approx 3.5 inches. The yoke is 5.5 total. It fits about 3/4 into the output shaft. If I made the yoke shorter it could give me room to fit the driveshaft on and I would have the same yoke........Interesting point about the spedo gear. I'm going to take it out and see if I can fit the yoke on further. The spedometer fitting as I'll call it doesn't have gears in it. It's just a metal cylindar that bottoms out at the bottom of the case. Could it be the wrong type of spedometer fitting or something like that?

Anyway, great tip......I'll report back this weekend when I have time to crawl under the truck again. Actually, I'll make my teenage son do the crawling. :-)

John

I sent the mail before thinking on this one.... your right , the obstruction is in the tranny. I can't remove it.

I did this swap without performing any precise measurements. On paper the T10 and the Saginaw were the same dimensions.Boy are they close!

The reason I keep going back to cutting the yoke is that the yoke was $30 bucks. I got it from a guy in Calif. If I ever needed to put the Saginaw back I might not be able to if I cut the drive shaft. The Saginaw is a 28 spline output and the T10 is a 16 spline output . The yoke outer dimensions are the exact same size. I thought I was in 'Fat City".

On paper the case dimensions were the same on the T10 and Saginaw.......I'll physically measure and report on the actual over the weekend.

My son and I are going through this together. He's 17 and is not happy that the truck is not running. The good weather is finally here in New England. A

17 year old with a 1960 Apache, V8, 4 speed is dieing to get it on the road! So am I.

Regards,

John

BTW...twice the Saginaw got jammed between 1st and 2nd 3 times in the past year. I could fix it if I removed the tranny, opened the side cover and moved the gears. The third time made me swap it. The T10 seems like a much better quality tranny. .