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So, just use the yokes that take the larger GM universal that are listed above. The NEAPCO N3R-3-6081X, or the AAM 7812557 both give you the GM universal size, and you can mate them up with the Ford drive shaft with 2 Moog 447s, one on each end of the drive shaft. That makes it really simple, and stronger.

Finally someone who understands what I have been trying to say! Thanks Fred.


Mike--94MSP9C1
 

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Thanks Mike, and you others. Quite the bank of intel for the future. And a generally good title for searching. There's even been enough chat to point out differences between the aluminum and MMC variants.
 

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Finally someone who understands what I have been trying to say! Thanks Fred.


Mike--94MSP9C1
I got it the first time, that is why I did some further research, and found the alternate yokes. They were listed right under the OEM unit on Denny's Driveshafts.
 

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Discussion Starter #24
I am just glad we got this dialog going and found more alternatives to the slip yoke that I found. That is what I like about this message board- we work together to solve problems and I'll admit, I was not impressed with the 1310 joint. But, now that Fred found the others, I'm going to order one and swap out the yoke with the smaller joint for the larger one. I don't mind taking the hit on buying a paper weight if it helps us all as a community. FWIW- the 1310 is rated at 800 ft/lbs, and the 1350 at 1200 ft/lbs.
https://pssupply.com/torque-and-speed-ratings-for-universal-joint-driveshafts/
 

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The 1310 is 1.062", and the 1350 is 1.88", so interpolating that, the stock GM unit, at 1.125", should be about 1000 lb/ft. That is maximum short duration load.

According to the chart, the maximum instantaneous load interpolated for the Chevy universal should be about 1900 lb/ft.
 

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All fine and dandy til you start measuring the actual cross shaft dia.

Depending on brand and grade, I have seen 3R and 1310 have the same cross shaft dia , with the extra .062 made up in the cup and bearings.

Also, goes without saaying, if you use the weaker greasable joint, make sure to assemble it so the threaded grease hole is under compression when accelerating.

As in trying to close the hole , not open it.
 

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Discussion Starter #27
With the NEAPCO N3R-3-6081X we are back to being too long again. It will fit, but there is less than 1/4 of an inch forward movement in the driveshaft before it bottoms out in the transmission. For now, the stocker is back in the car. I'm going to order non-greaseable joints and install them in the 9c1 parts car driveshaft and use it.
 

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With the NEAPCO N3R-3-6081X we are back to being too long again. It will fit, but there is less than 1/4 of an inch forward movement in the driveshaft before it bottoms out in the transmission.
What bottoms first, spline or seal?
If spline, i have seen some 4l60s with a huge chamfer on the shaft making the last 3/8 or so not doing anything .
Not suggesting, but if you are looking for a little more room,,,,,,

Havent done it myself, as I dont have a 4l60 and just tossed money at mine with a custom driveshaft.
 

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Discussion Starter #29
It is the splines bottoming out. There is still about 1/2 to 3/4 of an inch before it hits the seal. I remember a friend's Corvette 700r4 output shaft had a flat end with no taper and was thinking...but not today.
 

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If the 1/4" clearance is with the rear in the air and fully relaxed, you might revisit my post on the 18th to check whether that clearance increases as the suspension is compressed. It may be only my car, or the affect of extended LCAs, but I theoretically could have installed the MMC shaft without milling off the end of the yoke by just compressing the suspension until the rear joint slipped past the pinion yoke.



Interested what you find. The only thing comes to mind is it would make it critical if replacing shocks not to getting a different brand with even a little longer stroke as it would increase potential of hard bind.
 

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What is the maximum length between the universal center, and the end of the yoke to not bind?
 

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It is the splines bottoming out. There is still about 1/2 to 3/4 of an inch before it hits the seal. I remember a friend's Corvette 700r4 output shaft had a flat end with no taper and was thinking...but not today.

My case too - a good fat 1/2" before hitting the seal. I knew milling less than half that amount from the end of the yoke (3/16") would not create bind.
 

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My case too - a good fat 1/2" before hitting the seal. I knew milling less than half that amount from the end of the yoke (3/16") would not create bind.
So what you are saying is to mill 3/16 off of a NEAPCO N3R-3-6081X would be sufficient to have a non binding fit?
 

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I believe the interference point is the end of the shaft to the plug in the yoke, isnt it?

The end of the shaft would need shortening if this is the case.

The heavy chamfer on the end (if it has it ) could be removed without loosing spline.
 

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Apologies. I know there must be multiple points of potential for confusion. Remember I'm working from the initial basis like others who needed a "longer driveshaft that was also a measurable material upgrade" after getting extended LCAs (in my case Gen I METCOs). These were advertised as 3/4" extended LCAs v. one or more others that are manufactured shorter to answer concern of "over-reducing" spline engagement if retaining stock shaft.


So 2 years ago I learned about the MMC shaft (not to be confused with Ford's other aluminum one), and tried to install it. No way. Too long by just a fraction. I originally thought.

Snipped from Post #181 from this thread:
https://www.impalassforum.com/vBulletin/5-drivetrain/271635-cheap-aluminum-driveshaft-those-extended-control-arms.html

[Note Clarification]
1. I ended up having 1/4" sliced off the end of the yoke to provide a safety measure of travel before bottoming out on the unfluted end [forward side] of the output shaft..

Which brings us to:

I believe the interference point is the end of the shaft to the plug in the yoke, isnt it?

The end of the shaft would need shortening if this is the case.

The heavy chamfer on the end (if it has it ) could be removed without loosing spline.

In my case, [MMC shaft - refitted with new conversion u-joints (listed in Post #67 of that thread above) - and using early METCO 'not quite' 3/4" extended LCAs], it turned out the yoke ran out of output shaft spline. Cutting off 1/4" of yoke still left some travel to the seal, and barely allowed bolting up the rear u-joint. I recall my outshaft had a chamfer, but (again in my configuration) that was not the hit point.


The OPs issue is different from mine in that he's installing the 3/4" longer shaft without any type of extended LCAs.

My biggest takeway from all this is just to compress the suspension a little and see if installation is possible and then let it hang free to check that some net clearance is retained before binding seal or between yoke and shaft.


And final final note - I saw from that other thread where I originally caught reference to an "early '60's Pontiac" application for an alternate yoke (I falsely recalled it earlier here as a "GTO yoke").


More confusion to follow. ;)
 

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I checked on the "GTO" yoke, and it has a different spline count.
 

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So what you are saying is to mill 3/16 off of a NEAPCO N3R-3-6081X would be sufficient to have a non binding fit?
Follow-on Fred. I used the retrofit joints in listed in Post #67 of this thread:
https://www.impalassforum.com/vBulletin/5-drivetrain/271635-cheap-aluminum-driveshaft-those-extended-control-arms.html

But it was a different starting base than the OP's. It sounds like he's taking a similar (tedious but ultimately 'best-fit') route with his configuration as I did mine.

To yours and Gerry's points it strikes me "too long an output shaft" could surface as an additional issue on top of my simple "too long a yoke" was.
 

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I checked on the "GTO" yoke, and it has a different spline count.

Check - thanks. All this has been over 2 years back, and I may have found that the case, but ended up definitely easier finding that perfect machine shop (30 miles away) to just alter my original yoke. And found it interesting reviewing that old thread that even after all my 'measure 20 times - cut once' that I must have wussed out and added a 1/16 to the 3/16" what I distinctly remember calculating as perfect shortening. lol
 

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I did not learn anything new from the other thread.
 

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To further confuse.

Way back, in 70 and older,
The Chev used the 1310 and Olds Pontiac Buick used 3R.

My 70 Cutlass's used a short 3R yoke with its 4 speed and TH 350 ( think the same as "glide too"

I think the "GTO" reference would be differentiating from Chev 1310.
BUT this would only apply to stick cars as the GTO auto was always a TH400 with large spline.

The TH350, late Glide, 70 down sticks, 7004R, 4L60 , all were 27 spline far as I knew.

About 72-and up all the typical GM cars went R3 and also, I think, got the longer trans yoke that most are used to seeing.
 
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