Driveshaft for '68 Fury (2-piece / bushing ?)

[MoPar~Man]

This was posted recently to FB. Someone with a 68 Sport Fury, wondering if this is a 2 piece driveshaft with a rubber bushing connecting them. Were they really made like this? My '67 Monaco has nothing like this (the photo is at the differential end).

He's asking "If I have a new 1 piece made will I have vibration problems?" I would guess not if it's balanced. Mine has a bit of a flywheel at the transmission end, I don't see that on this one.

 

[bronze turbine]

Yes, they really did have 2-piece driveshafts with rubber in between. My '68 New Yorker has it. When we bought our '68 300 it did not have this 2-piece driveshaft but it was dented and the car had a vibration so we used the 2-piece driveshaft from the New Yorker until we were able to have a new driveshaft made. It was supposed to make the cars smoother and quieter, but I doubt you would really notice a difference. You would think that rubber would tear up but the 2-piece driveshaft we have besides being almost 60 years old has over 120,000 miles on it and is still fine. I don't think you could buy one new today. I think it's gone the way of the reverse threaded lug nuts. I would be interested in hearing more about these driveshafts since it seems to me they are hardly mentioned.

 

[CBODY67]

This is a different "two-piece driveshaft" than many are used to seeing.

I'm wondering if this was some engineering experimentation that was supposed to make the car run smoother, or they were chasing some harmonic that the rubber dampened? Might even have been a pesky vendor that wanted to sell those driveshafts like that, as the "next new thing"?

Sometimes, the OEMs will try things in a small model run, then track those cars as to warranty claims to see if the change worked before putting it into normal production. Back in the 1980s, there was mention of a desire to make Imperials (somewhere in the 1964-1966 time frame) run smoother and quieter, as they were seriously competing with Cadillac to build Imperial sales.

They had a group (about 60 or so?) of 413s built to really tight tolerances to decrease engine noise and vibration. Then they were going to track those cars to see if any complaints were made about engines not being as smooth as they should be. All was working to plan. Monitoring network was in place. Engines were built to min-spec tolerances and made ready to ship to the assy plant. The plan got de-railed when the wrong truck driver picked up the special engines and they went into regular Chryslers instead of Imperials. Chronicled in the "WPC News", back then.

Best way to proceed is to get a quality drive shaft shop to build a new one and be done with it. Balancing and all.

Just some thoughts,
CBODY67

 

[bronze turbine]

I've seen that 2-piece driveshaft mentioned in Chrysler sales literature so it's definitely a factory item.

 

[bronze turbine]

I just did a quick google search and I found this is called a "tube-in-tube rubber-isolated driveshaft".

 

[Big_John]

I just did a quick google search and I found this is called a "tube-in-tube rubber-isolated driveshaft".

They used those driveshafts in a lot of cars, not just Chryslers.

Generally speaking, they aren't called "2 piece" as that's what you call a driveshaft with a carrier bearing and basically 3 u-joints. That's kind of nit-picking on my part, but it's sometimes important to know if you are dealing with a driveshaft shop and you want to use the correct terminology.

Here's a pic of a 2-piece Imperial driveshaft that also happens to be rubber insolated.

 

[MoPar~Man]

My searching just now, came across mention of these rubber-isolated shafts in a couple of ford groups, specifically mustang and cougar. Interestingly both mention 1968.

Also an FBBO post from 2016 where someone discovered one of these on a '67 318 Charger with non-original drive train (converted from 3spd to 4spd). Someone in that thread said "Never seen one on a MoPar but plenty of Fords used them in the 60's" and "These insulated drive shafts were common and mainly came on the 6 cyl, or small blk applications. The idea was the insulator damped the shift shock to the rear end and made for a more quite ride. It is not performance, and I would ditch the shaft for a solid tube shaft."

Also some talk of these being in early 70's slant-6 Darts and Valiants. I can't see the reason here being to give a more quiet ride.

But curious - with the addition of more rubber isolation in C-bodies in or after '69 and the torsion-quiet thing and isolated mount upper control arms, I would think that if any Mopar had rubber 2-piece drive shaft it would be Imperial?

So I wonder what played more of a role in determining when a car would have these rubber-isolated 2-piece drive shafts?

- transmission (standard vs auto)
- engine (small block/slant-6 vs big block)
- rear end (2.76 vs 3.x)
- high-line (Chrysler/Imperial) vs economy (Plymouth/Dodge)

You'd think it would show up on a build sheet?

 

[mrfury68]

Wow, I've been into these cars for nearly 50 years and this is the first I have seen or heard about these driveshafts. Learn something new everyday.

 

[CBODY67]

I would suspect these rubber-infused driveshafts were indeed to quieten some noise transfer and minimize any harmonics which the long tube would transfer/amplify.

The OEMs used several methods, singularly or in combination, over the years. One is the driveshafts with the smaller end on the front, as the tube diameter decreases prior to the u-joint. This could also allow the use of smaller u-joints and transmission yokes. The rubber-isolated driveshafts seemed to accomplish this with the use of two different tubes, separated by the rubber isolators.

Additionally, the OEMs also inserted long pieces of cardboard into the tubes, too. Otherwise, they could, as I recall reading about Ford doing in some model years, insert rubber do-nuts into the tubes. Usually two of them. End result, the resonant frequency of the driveshaft tube was moved out of the frequency range which was causing issues.

In the 1980s, we had issues on manual transmission 3/4 and 1-ton pickups (not Dodge) having a ringing sound transmitted by the driveshaft. As we sold a lot of them, I became friends with a good driveshaft shop we used to build complete new 1-piece driveshafts. Of course, the tubing they could get was the same size, end to end. Absent any cardboard (which might catch fire during the welding processes), their solution was to drill a 3/8" hole at one end of the tube and pout a two-part expanding urethane foam mixture into the tube. This generally worked well, until the foam broke apart and caused a vibration. Our service customers were long-time customers and knew we'd take care of that, so no issues among friends. This usually happened several years later, so we had a new shaft built for them.

Just some thoughts and observations,
CBODY67

 

[Vaanth]

Chrysler introduced the Internal Vibration Absorber (IVA) propeller shaft (aka drive shaft) for certain applications for the 1966 model year. Applications were determined through Noise/Vibration/Harshness (NVH) studies. Two approaches include the addition of the inertia ring at the front of the shaft, or a rubber isolation with inner and outer shells added at the rear of the shaft. These approaches were phased out in later years as other NVH control methods were used in body structure, suspension mounting, etc. 1966 was also when the constant velocity joints were dropped in favor of cross and roller universal joints on all models except Imperial.

From:

Additional industry-wide information for the IVA Propeller Shaft can be found in SAE technical paper, " Axle Noise Control - The IVA Propeller Shaft", Product Code 690259, Jan 31, 1969.

 

[carrman]

My '68 Newport had one until last year. I replaced with a new custom made drive line with bigger u-joints