Is my driveshaft modified?

[soundcontrol]

Hmm, took my driveshaft off today. First of all, the bolts holding the rear u-joint to the third member was long metric allen bolts(!), going thru with a nut on the end.... Then I notice a weld on my driveshaft, close to the rear u-joint, there not supposed to be welded there right? Is my driveshaft modified?

[roadman5312]

I would say so, and metric fasteners not

[brads70]

Mine doesn't look like that....

[soundcontrol]

Yep, confirmed, I got a driveshaft with a 1350 u-joint in front and a smaller 7290 rear.
I'm getting a new all 1350 driveshaft from DrDiff, I already got a new 3.55 third member, just need to change the yoke.

[Chryco Psycho]

Changing the yolk could lead to problems if it has a crush sleeve it will mess with the brg preload , if it has shims you should be OK

[soundcontrol]

Changing the yolk could lead to problems if it has a crush sleeve it will mess with the brg preload , if it has shims you should be OK

I dont know much about the rear end. What is crush sleeve and brg preload? My new third member is a complete one from DrDiff. (not the one on the car now).

[1 Wild R/T]

If Cass built it he should be able to tell you if it has a crush sleeve or not..... If it does swapping the yoke without taking the carrier out & adding a shim to increase the crush is questionable... The better approach would be to add a crush sleeve eliminator...

[soundcontrol]

Yeah, Cass built it, I'll ask him. Now I gotta read up on this so I learn something.


Few hrs later... So now I know what a crush sleeve is.
Here a video that explains it for anyone who is interested and did not know, (like me). Not a Mopar, but I'll get the function of it.
https://www.youtube.com/watch?v=mByWwsrMUMQ

[soundcontrol]

Good news for me is that Cass already put a crush sleeve eliminator in my new case, so changing the yoke should be easy.

[rUNCHARGER]

Yes: Cass is fortunately much smarter than the guy that welded that driveshaft.

Sheldon

[Topcat]

this might be needed.

http://www.ebay.com/itm/Mopar-Rear-Axle-Yoke-Holding-Tool-PROBLEM-SOLVER-Cuda-Charger-Dart-R-T-GTX-/321621889375?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4ae228915f#ht_940wt_788

[soundcontrol]

I'm assuming a previous owner found a suregrip third member with the smaller u-joint and just cut the driveshaft from the donor car as a quick fix.
A new driveshaft might also fix some vibrations I had, that I thought was something else. I did not see this when I bought it, even though I examined the car on a lift.
Was mostly looking for rust under though.
That tool was a smart one, I saw Rick Ehrnberg came up with it, I believe he is behind the selector support I got for the steering also.

[soundcontrol]

Driveshaft lenghts confuse me now, trying to measure it, to get a new one, looking at this:
http://board.moparts.org/ubbthreads/upload2/4563759-PartNoDriveshafts.pdf
Why is there 2 different 340-727-8.3/4 lenghts avaiable? And very close in lenght also...And was there a 318/727 option? with a different longer driveshaft 1970...
Hmmm. My car is a G code, don't know if it came with a 727 or a 904 originally. I measure 49" from yoke CL to end of tailhousing, then I guess driveshaft lenght is
measured center of u-joints right? If that correct, it gotta be one of the 2 shorter driveshafts.