costpenn

Last night, I installed the driveshaft in the 72 442 vert I'm doing. I've done a TH400 to 4 speed changeover and am worried about two things

1) the driveshaft just barely went in length wise. It only shows about 3/4 of an inch yoke exposed between the front yoke fillet and the rear transmission seal. Is his right? I bought a "supposed" M/T shaft without the rubber bushing.

2) the rear joint is held to the rear end yoke by the straps with the to bolts. I had to tighten the hell out of them to get them to clamp down at all on the u joint cups. Is this correct?

Thanks

oldcutlass

Got some pictures, the 3/4's of an inch sounds about right. When you say tighten the hell out of it, do you think the threads were boogered up, and are the cups bottomed out in the clamp?

RandyS

Do the sides of the bearing cups touch the trans yoke evenly? What I'm wondering is are the u-joints too small in diameter for your yoke?

costpenn

The bolts are in as far as they will go - it' s actually torqued about 25 foot pounds more than called for in th CSM.

costpenn

The cup fits in there well. I'm just worried about the thing coming undone going down the road due to a cup slipping out. I'm thinking about grinding down the strap face a 32nd or so and see if it feels better.

joe_padavano

Proper driveshaft length must account for both the transmission AND the rear axle. The various GM axles have different centerline-to-pinion flange dimensions that vary up to an inch. In addition, the different axle flanges use different U-joints. Sounds like you have a driveshaft for a different axle.

droldsmorland

Find a good driveshaft house in your area...Fleet Pride or similar. They make, balance and stock all driveline parts, mostly big truck but lighter duty truck & automotive as well. Or give Dennys Driveshaft a call or internet search. Dennys has some good printable diagram pictures with dimension’s showing what you need to measure and where for both the U-joint series (size) and proper shaft lengths. Hybrid U-joints are made to accommodate two different series cups though its just as easy to have the rear yoke cut off the shaft and have the correct mate to your pinion yoke welded on. Or replace the pinion yoke to match the drive shaft.
IMO with a 4 speed go with solid U-joints over greaseable, they are stronger.
You want to make sure that when the rear end articulates it’s not driving the yoke into the trans tail shaft or so loose that it will come out of the splines when the rear is at full deflection. If in doubt remove the rear springs and jack the rear end up/down to fully articulate.
Always clean the bolts straps saddles cups threaded holes etc. I don’t recommend filing them. If they don’t fit you have a compatibility issue. Don’t mess with mismatches on a drive line. Always use a dab of blue thread locker (Loctite # 242) on oil free fasteners for all driveline fasteners.
Straps and bolts will wear & stretch. Buy some new (not off shore) straps & bolts...cheap insurance.

dc2x4drvr

Driveshaft King does nice work. Is there a chance your rearend pinion has been changed for a larger U Joint? You shouldn't have to do any grinding on the straps, and over torqueing the small bolts isn't a good idea, put the straps on and measure the ID, and check OD on the U joints, you have a mismatch somewhere..

oldcutlass

Again pictures are worth 1000 words, please post pic's of your front and rear flanges and the distance the yoke sticks out of the trans.

costpenn

Lance, the U-joint fits perfectly into the circumference of the yoke on the rear end and it's the original 8.5 corporate rear end that had never been messed with. It's the right joint for sure, I'm wondering if maybe the straps are the wrong size. The shaft seems to be pretty secure - maybe it's just in my head that I shouldn't have had to run the bolts all the way in before the strap began to touch the U-joint cap, but I'm still going to call Driveshaft King. Thanks!

costpenn

Will get some pics up this afternoon.

jfb

1 more thought for cheap insurance and talk to a drive line shop first about it,How about u bolts for more strength. I have u bolts and have had much more peace of mind afterwards and have had 0 problems since straps can become a hazard with more severe use.

oldcutlass

The strap is designed to sit flat on the yoke and ujoint caps with the bolts all the way in.

costpenn

Sorry about the delay on the pics. Let me know your thoughts as to whether to start over with a new shaft. I was hoping to use this this one since it's an original TH350/M20 GM shaft with the taper, but it aint worth a shaft coming loose while I'm FRYING up those Wide Ovals

MDchanic

The straps on the rear joints look right to me.

The slipyoke looks to be a little deep in the transmission, but that will depend on the position of the rear suspension - up or down.

- Eric

ah64pilot

Hey Joe, having done a few TH-350 to TH-400 conversions I can tell you that the original TH-350 driveshaft has to be shortened 1" and the yoke changed to a TH-400 yoke.

Given that you have an M20 driveshaft I'm not sure how long it is but if you would like I can measure the length of my 2 driveshafts and the amount the yoke sticks out of the transmission. Also, the pinion looks right to me. The u-joint caps are secured on the "Y" axis by the recesses in the pinion yoke and on the "X" axis by the straps. As long as it's tight I think you're in good shape. Maybe someone else will have something to add.

costpenn

Our Houston connection!!!! How are things? Seriously, we need to do a big CO Texas meet sometime in early 2012. Maybe you and JoeW31 could make it to our Spring Zone Show? There will be drag racing.....

If you wouldn't mind measuring, that would be awesome.

ah64pilot

On the transmission side I measured the distance from the seal lip (metal flange) to the start of the tapered area of the yoke and I got 3/4". I also measured the distance from the seal lip (metal flange) to the center of the u-joint bearing cap and got 2 1/2". I can measure total length but it'll have to wait till tomorrow.

I would love to meet up with the Dallas boys again soon I might have a new rear end to test out early next year as well...the timing might be perfect.

oldcutlass

The straps and install at the rear looks perfect. The front looks like it will work fine if the car is sitting 4 wheels down on the ground. If you have any doubts load the trunk with some weight until the rear bottoms out and then check your position to make sure your yoke does not get rammed into the trans.

garys 68

I just went through this and had a custom driveshaft made t fit a T10 and chevy axle.
Rear caps look fine. Either there was old locktite binding up the threads as they went in, or your U joint caps were binding on the trans yoke lips as it was being tightened.
On the trans yoke, you're fine with 3/4" if the cars weight is on the rear wheels/axle. When I cycled the rear axle through it's full travel, the front yoke moves very little, maybe 1/4" You need nearly 3/4" space in order to slide the rear dviveshaft U joint in place. Mine is right at 3/4" too, been driving all summer like that.
DSCN0492.jpg

costpenn

Thanks for the evaluation - my car is on he ground with the engine in, but no interior nor fluids loaded. I measured it a bit more precisely - it's almost an inch so I should be good there. I'll check those straps on last time and make sure they have a good grip on the u joint cup.

Need to do a run down to Dublin and load up on some Dublin Dr. Pepper might be a fun run.

costpenn

Thanks for the pic. I feel a lot better about it now.

oldcutlass

Good luck with that, Dr Pepper in Waco sued them and they cannot make it there anymore. No more Dublin DP.

costpenn

Sorry to dig up this old chestnut, but the issues just keep right on coming on this resto.

Got the correct 7451959 wheel bearings in, and the wheel endplay/run out issue is solved. Went for a spin around the block to confirm it, and then ANOTHER issue came up. Started getting a driveline clunking sound, and it kept getting progressively worse. (I didnt drive much more than a 1/2 mile). Pulled it into the garage, jacked it up and both U-joint differential yoke caps were missing, and the unprotected U-joint was wedged in the gap between the ears.

Like I pointed out above, I knew something was wrong with me having to tighten down the strap bolts so much to get it even a little snug. I checked the U-joint cap O.D. - it's 1 1/8th just like what it's supposed to have. (Precision # 534 U-joint) The straps looked OK before I installed them (not now!!) and if you put a U-joint cap in the "crook" of the strap, it seems to fit perfectly. I am at a loss on how to fix this. Maybe the cap is too small for the pinion yoke, but it sure seems to fit OK.

I'm wondering if maybe the strap material is too thick where the bolts go through it. I'm going to buy some new ones at O'Reilly (Precision # 530) and see if I get anymore interference. Anyone else have any other ideas?

oldcutlass

Are you saying the Ujoint caps slipped throught rear yoke straps? Or the other ones in the driveshaft?

dc2x4drvr

Joe, I measured my caps and got 1.125, so you've got the correct u joint. I'll measure my straps tomorrow, this is a strange problem..
If you want come over and take a look at my driveshaft u joint, and straps.

oldcutlass

There is a lip on the yoke that secure the caps from moving outwards. The strap secures the ujoint to the yoke in the lips on each side. The internal clips sometimes need to be installed to keep things centered.

garys 68

What oldcutlas said. There are lips on the yoke, the caps should be seated inside that.
Just curious if the U joint matches the yoke. Is it a 1310, 1330, or 1350?
Check out this for dimensions:
http://www.actionmachineinc.com/ujoi...ringguide.aspx

redoldsman

X3 on what oldcutlass and gary68 said about the lips on the yoke. Don't ask me how I know but it was an expensive lesson.

X2 on Drive Shaft King. Good guys and fair prices.

costpenn

Ah ha!!

So there is something on the outer lip of the yoke where the bearing cap sits like a tang that would prevent the bearing from sliding out? Mine does not have anything like that at all. Would installing the inner clips on those caps accomplish the same purpose?

MDchanic

Yes. The inner clips should always be installed unless they physically don't fit.

The yoke on the input shaft of the differential doesn't always have raised ridges at the "outside" to keep the caps from flying off, but the clips should engage the "inside" edges to hold the caps in.

- Eric

garys 68

There's your problem.......
Either there's a tang on the yoke that holds the caps in. A groove in the outside of the yoke for the e clip. Or the inside c clips that fit in the groove on the U joint.
See the lower example in the link I posted above.

MDchanic

Just to make it clear with the link you posted:

Some yokes are like this, and have little tabs at the outside to keep the caps from flying off:



Other caps are like this, and require the inner snap rings to keep the caps on:



- Eric

oldcutlass

That link explains it perfectly Gary.

garys 68

As long as you're checking over the driveshaft, make sure the correct retainers are on the pressed in caps on the driveshaft itself. If you look at the pic I posted a few months ago, you'll see the outside e clip style.

costpenn

Thanks to all of you. Mine needs the inner clips installed to prevent the lateral movement. Feel like a MORON for not figuring it out myself.

Joe

costpenn

I believe, but now I'm not sure of anything, that mine uses the inner clips on all four cups of the front joint, and the two pressed in ones to the shaft on the rear one. They look and feel right.

costpenn

Lance thanks for the offer, but I think I figured it out - see above. Are you bringing that bad boy of yours to the Zone Meet?

garys 68

They can press in pretty tight but they still need some type of clip to hold them in. Be sure the clips are in the others too.

oldcutlass

So sorry we did not figure this out months ago when you first brought up the issue. Glad that it did not create any other issues.