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Feel like I'm having a one-sided conversation here, but I bought a Mopar adjustable pinion snubber from Jeg's...

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Feel like I'm having a one-sided conversation here, but I bought a Mopar adjustable pinion snubber from Jeg's...

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What rpm is the engine turning when the vibration starts and can you drive through it? Say it starts at 3500 and vibrates til 4800??? will it vibrate in neutral at the same rpm???

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I don't like pinion snubbers. They hinder suspension travel. If the universal joint is going that high from axle wrap it's the fault of weak leaf springs.

Is the vibration speed or rpm related?


I correct my statement. I don't like adjustable pinion snubbers. The factory one will not hinder travel.

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The snubber should help the pinion angle stay in a safe area if the rear springs are overcome by the weight transfer of the car. Many say no pinion snubber is needed however I am of the opinion that if you have to have soft springs to get the tires planted a pinion snubber will be very helpful in keeping the pinion angle safe. What springs are in the car now? I would def. have the drive shaft balanced by a known good shop with the new u-joints installed. That said let them put the joints in if you do not have the proper tools or experience. If this is the case as if you can watch. I've seen several shafts ruined by inexperienced, overzealous shadetree mechanics. At the age of 16 I started that list! If you have trouble getting a response shoot me a PM or I'd be hapy to share my experiences.

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Sounds good. Make sure to check all of the trans bolts, etc. while you are under there. I had a nasty driveshaft vibarto and it shook all kinds of bolts loose and almost wrecked the bellhousing. I also suspect that is ate up the trans mount. Had a new d-shaft cut and all was good other than lots and lots of loose bolts. I learn the hard way so others don't...

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What did you determine on the length?
Length should be 50.39" ctr-ctr.

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Driveshaft shop says the front u joint is bad. They'll replace it with a solid joint, straighten, and balance it. Should be back in the car this evening. Maybe I can take a test drive without getting pulled over this time...

Thanks,

Scott

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Are you running a poly transmission mount, or a stock (rubber) transmission mount?

What is the angle of your transmission centerline? Up or down toward the rear?

What is the angle of your pinion centerline? Up or down toward the rear?

How much driveshaft travel before the slip yoke bottoms out inside the transmission?

Does the slip yoke fit fairly tight inside the transmsission tail bushing?

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Driveshaft shop says the front u joint is bad. They'll replace it with a solid joint, straighten, and balance it. Should be back in the car this evening. Maybe I can take a test drive without getting pulled over this time...

Thanks,

Scott

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Why would the front joint have gone bad if the rear was what hit the floor?

Also STRAIGHTEN ??? , straighten WHAT ???

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Whoa whoa whoa....

If you are rolling along at 80 mph and the vibration is there...and you put the car in N and the vibration goes away...

would you not want to investigate the converter/flexplate/flywheel balance? If the driveline was causing this the vibrato would still be there even in N when the car is rolling. Personally I'd think about finding a different driveshaft shop. It is straight or it's not. If not it needs to be retubed or it will never be correct.

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Sorry man I did not mean to sound harsh. 'Just thinking out loud to isolate your problem. You'll get it, just takes time and some new gray hair.

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What did you determine on the length?
Length should be 50.39" ctr-ctr.

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Scott,

Hate to chime in late here but I now find myself in your situation, just a little bit worse... Funny thing is I have the same set up in my car, 68 Road Runner-426-727-4.10 dana and live in Virginia...go figure... Car is a total restoration,and I had my drive shaft balanced prior to installation with new joints. Up to this point I had only driven the car around the neighborhood and a few small burnouts in front of the housewith no issues. I drove the car through town (3 miles/40MPH) for the alignment. After that was done I took it out for the highway run it it felt really good under throttle to about 70 or so and then I let off the throttle and it started the vibrations pretty strong. I slowed down and varied speeds and it seemed like it was more pronounced during deceleration. I took it home and put it up on the lift and everything looked and felt OK. In my mind I was thinking something from the rear end since the vibration was in the body and not the steering wheel. I took it out one more time and still had the same problem...all of a sudden the vibration went away and for a second or so I was pretty happy until I looked out in the mirror and saw nothing but smoke...and I mean a LOT of smoke... The heavy smoke cleared up but I was still getting intermittent puffs as I slowed down and got off the highway. Once off I pulled into a parking lot and discovered trany fluid everwhere under the car. I nursed the car back to the garage but had to go under 25 MPH as the car had vibrations bad enough that I did not want to chance anything by pushing it. Once under the car I found the tail shaft housing in two pieces, it broke just after the mount. Once I got things cleaned up a bit I pulled the driveshaft (the weights are still in place)and the U-joints still feel good through full travel. I spun the shaft out the back of the tranny and it is straight as best as I can visibly see. Good thing was that there was no damage to the body other than the mess from the tranny fluid.
This happened last weekend and I had to leave town before I could have the driveshaft re-checked... I also still need to drop the tranny pan and see if there may be any suprises...I love this hobby...

Anyone else ever bust a tailshaft housing???

Jim
68 Hemi Road Runner

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Is the vibration in the steering wheel or in the seat of your pants?

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Is the vibration in the steering wheel or in the seat of your pants?

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Vibration is in the seat of my pants.

Thanks,

Scott

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