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Bob -

Here are the measurements from the coupe:

Tranny : 24 1/4"
Shaft : 53 7/8" end of cradle loop to end of cradle loop
Pinion Yoke: 4 3/8"

I didn't take the measurement for the slack in yoke, but guessing right around 1".

The pinion yoke probably isn't original, so length could be reason the shaft is very, very near the measurement of the FMX shaft length...that surprised me.

And to previous post, I haven't experienced any issues with a non rubber split shaft.

Also, seeing that you're from NJ, I certainly hope you are not a Giants fan with all this help! Originally being from NE PA, us Eagle fans look a little leary towards the Giant fans...:beer:
 

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Discussion Starter #22 (Edited)
Elroy said:
Pinion Yoke: 4 3/8"

I didn't take the measurement for the slack in yoke, but guessing right around 1".

The pinion yoke probably isn't original, so length could be reason the shaft is very, very near the measurement of the FMX shaft length...that surprised me.
Thanks Rod, will check shaft length against the ones I have. The pinon yoke, what protrudes from the front of the differential carrier right? I am confused by what you mean by slack in that? I take it from your explanation that your pinion yoke would be shorter then resulting in a longer driveshaft (close to or FMX length).

I think the way the lengths are specified are not end to end of the driveshaft (apparently cup center to cup center?), I found mine to be longer than any of the lengths that Dave posted from his MPC.

Elroy said:
And to previous post, I haven't experienced any issues with a non rubber split shaft.
Me neither, I ran solid one for many years without issue.

Elroy said:
Also, seeing that you're from NJ, I certainly hope you are not a Giants fan with all this help! Originally being from NE PA, us Eagle fans look a little leary towards the Giant fans...:beer:
Who are the Giants? For that matter, who are the Eagles? Is that a sports reference? Yes, Rod, you are talking to a bonafide motor head. I honestly do not the have time or inclination to sit around and watch TV almost at all, let alone sports! I would go to a game in person though, haven't done that is while...

Have a great weekend and thank you for your ongoing interest and help.

Bob
 

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Bob -

Sorry for the confusion.....yes, the pinion yoke is the piece protruding from the third member. Sometimes these come in different lengths, depending what application the rear came from (only issue is if the third member has been a transplant).

The slack in the yoke that I was referring to is the slack between the driveshaft yoke and the tranny rear. You need the slack so the driveline doesn't bind as the suspension moves (up and down, and when rear rotates a little when you plant the tires...) - part of the yoke sleeve that is showing.

Have a great one!

Rod
 

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Discussion Starter #24 (Edited)
Elroy said:
Sorry for the confusion.....yes, the pinion yoke is the piece protruding from the third member. Sometimes these come in different lengths, depending what application the rear came from (only issue is if the third member has been a transplant).
Thanks for the clarification Rod.

Elroy said:
The slack in the yoke that I was referring to is the slack between the driveshaft yoke and the tranny rear. You need the slack so the driveline doesn't bind as the suspension moves (up and down, and when rear rotates a little when you plant the tires...) - part of the yoke sleeve that is showing.
Gotcha, thanks.

Last question (and I think I already know the answer): "end of cradle loop to end of cradle loop" basically means the length of the extremities of the driveshaft, from one extreme to the other, which is the outside edge of one hole that the U-joint cup goes into to the same thing on the other end, correct?

Amazing how hard (at least for you and I) it is to describe the part of the driveshaft we are talking about! There must be a more succinct description, but I don't know what that would be...

Thanks again Rod.

Bob
 

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1969XR7Vert said:
Last question (and I think I already know the answer): "end of cradle loop to end of cradle loop" basically means the length of the extremities of the driveshaft, from one extreme to the other, which is the outside edge of one hole that the U-joint cup goes into to the same thing on the other end, correct?
You are correct!

1969XR7Vert said:
Amazing how hard (at least for you and I) it is to describe the part of the driveshaft we are talking about! There must be a more succinct description, but I don't know what that would be...
Next time, maybe pictures......

Rod

Ps - notice that I split up the quotes this time??
 

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Discussion Starter #26
Alles klar, Herr Kommissar!

Good Job on all Rod (and you learned how to quote in parts, very good!).

I will confirm tonight, but I am pretty sure (going by what you reported) that the FMX driveshaft is the right length (wouldn't that be nice).

You have been a tremendous help. Thank you for your willingness to provide information and the time it took to get and report it, it is very much appreciated.

:beer:

Bob
 

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Discussion Starter #27
Measurements of what I have

Okay, my FMX driveshaft measures 55". Seems to me that the MPC listings must be shorter, maybe U joint cup center to center?, as the dimensions of "real" ones are invariably coming up longer (end to end measurement).

My Pinion Yoke is 3 7/8", but I am probably not measuring it the same as Rod. I measured from the front of the seal protector to the edge of the U joint cup where the U bolts go through the yoke. If I had included the protector or measured from the bearing retainer flange, I would probably get 4 3/8". Rod, any comment?

4 Speed Trans, must be the same at 24 1/4", I included the output shaft protrusion from the tailshaft, guessing Rod measured only to the end of the tailshaft.

Looks like driveshaft shortening for toploader is in my future.

Bob
 

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1969XR7Vert said:
My Pinion Yoke is 3 7/8", but I am probably not measuring it the same as Rod. I measured from the front of the seal protector to the edge of the U joint cup where the U bolts go through the yoke. If I had included the protector or measured from the bearing retainer flange, I would probably get 4 3/8". Rod, any comment?

Bob
Bob -

Same measuring method as you did assuming you mean outer edge of cup. As stated earlier, mine might have been a transplant. I can't remember if I used the original pinion yoke or just left the one that came with the newer upgraded third member. The pinion yokes lengths vary from application to application.....9" inch rears are pretty interchangable, but the pinion yoke varies in length.

Tranny's are probably same size. There really is only two lengths I believe, ours and the 27" Torino's.

I'll also try to get you the part # for the correct shifter mounting plate if you're using a Hurst. Having the right one will ensure the shifter alignment is true into the car itself - that or did what I did years ago and heat the base of the shifter handle and bend - not particularily a good idea....

You might be best to just wait until you get ready to put everything together - try your shaft, if it doesn't fit, take it to the shop, then have them cut it down, reweld and balance - if there is one nearby. They can usually turn them around very quickly - usually a couple of hours. Just be careful to incorporate slip slack in your measurement.

Continued, Best of luck!

Rod
 

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Discussion Starter #29
Good "Sticky" material I thought and here is what in particular I wanted to make readily available:

The MPC for 1969 Cougars lists 5 different driveshafts.
C9WY - A 53 9/16" 351 w/ FMX
C9WY - B 53 1/4" 351 w/ M/T
C8WY - B 49 41/64" 390/428 w/ C6
C7WY - B 53 1/32" 390 & B302 w/ MT
C8WY - A 53" 428 w/ MT
E-Bob
 
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OK, I have a 69 Eliminator that Im putting back together. Its not been running in probably 15 years. The driveshaft apears to be the correct length but, I cannot connect the two. The yoke engages fine but, I cannot push it any further forward and i still hit the rear end yoke. Ive never had this issue before. Wrong yoke? Help
 

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Discussion Starter #31
Does the trans yoke go all the way into the trans until the knuckle (that the U-joint cups go into) hits the seal in the back of the trans? If no, either the yoke has twisted splines, the output shaft of the trans does, or both.

Also, did you change differential carriers? There are a few different sized yokes for the carrier, some longer than others, some for different sized U-joints.

Hope this helps. If you have further questions post again and give more details.

Regards,

Bob
 

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Like Bob says I've seen the splines slightly twisted in the yoke that give the results you describe. Not easy to see the twist
 

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If I ever start up a punk band I'm calling it "twisted yoke"! I remeber scouring the internet for lenght and info for this when I put my AOD in never found it - I agree this is a very useful reference. BTW - FMX to AOD (from a late 80's truck/van) needs to lose 1" if anybody cares.
I'm not sure on the 2 piece shafts either? Seems like they are more common on manuals but you do see them on different apps sometimes? Could it be it was handy when they were building and just used it anyway..? IDK
 

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Discussion Starter #34
My parts car (AT) had the two piece driveshaft. I would never use one myself.
 

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I know this is an old thread, but I have a '69 XR7 351W-FMX and I did a 4spd top loader conversion back in 1987 and re-used the same drive shaft. The local Ford dealer provided measurements and they were very close. I have no issues with the yoke bottoming out inside the trans.
Just my $0.02
cheers
James
 

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Discussion Starter #36
I know this is an old thread, but I have a '69 XR7 351W-FMX and I did a 4spd top loader conversion back in 1987 and re-used the same drive shaft. The local Ford dealer provided measurements and they were very close. I have no issues with the yoke bottoming out inside the trans.
Just my $0.02
cheers
James

The difference between the FMX DS and MT DS is the MT shaft is 5/16" shorter. So, it is not too big a surprise that you made out okay. Me, I had mine cut, rebalanced and the new, strong, sealed Spicer joints put in.
 
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