I AM CURRENTLY HAVING A DRIVE LINE VIBRATION PROBLEM WITH MY 71 MAV. 2 DOOR 200 SIX AUTO. I RECENTLY SWITHED TO 5 LUGS WITH A 68 MUSTANG REAR IN GOOD CONDITION. THEM SWITCHED THE DRIVE SHAFT (NEW U JOINTS) STILL VIBRATION. SWITHED TO A 75 MAV REAREND STILL VIBRATION. THE VIBRATION SEEMS MORE LIKE A SURGE, NOT AT ALL STEADY. I HAVE TRIED THE USUAL TRICKS LIKE ROTATING THE DRIVE SHAFT 180 DEG. ANY ONE GOT ANY ADVICE? I HAVE DONE THIS TYPE OF SWAP A DOZEN TIMES BEFORE BUT THIS ONE HAS ME STUMPED! THANKS MARK
When did this problem begin to occur? Are you sure the vibration is coming from the driveline? Make sure that yout bellhousing bolts are tight...
Make sure driveshaft has 1 inch free travel into tranny with car setting to ride. Also check your pinion angle. Check u-joints for free rotation by hand in all directions. New joints may still bind. Put car in air with jack stands under rearend and have someone run it while you watch driveline. Tires need balanced??
While you're under there, it might be worth while to unbolt the driveline from the rear end and rotate it half a turn and bolt it back up. Had a Mustang once that vibrated, rotated it half turn, and the problem disappeared.
If you switched the rear end and the "vibration" started, then you changed the driveline and still had the "vibration" it must be in the rear end. You used two drivelines and even rotated one to see if that would help and all that work did nothing. You didn't have the vibration before the rear end was changed but you had it immediately after it was changed then it stands to reason it is in the rear end. If it makes a surging type of vibration and sound like vvrrrruuuuummmmm vvrrrruuuuummmmm vvrrrruuuuummmmm and the car seems to pull back a bit and then move forward slightly in regular intervals that are tied to your road speed then there are a couple of places to check. Check the tire balance. Check the oil level in the differential. Check the axle bearings in the rear end. ( I would just replace the axle bearing right off.) My bet is that they are bad. Replace them and try driving it again. If it isn't gone then you can check the other things. Oh, after you replace the bearings - fill the differential. It will lose some oil when you remove the axles.
Thanks for all of your advice. I have replaced the leaf springs with new 4 leaf units the rear shocks, the wheel bearing were replaced on the mustang rear. but not in the mav. rear. the third member was rebuilt with a used, but in good conditon 3.25 ring and pinion, and new instalation kit. I have tried 2 different drive shafts one with a ballancer on the yoke and one without but with new u joints in both. I also tried to use my old dif in the other housings, which only had 36,000 miles on it. but the vibration persists. Tires have been ballanced. could it be in the drums, one has a small place missing on the outer section of it, looks like someone tries to hammer it off. O rcould the axle be cocked to one side? It seemed that the rear could get out of square when I put it back in the car. Thanks again for your advice! Mark
You can check the driveshaft by jacking up the car and supporting it securely (gotta put the "safety" stuff in there) and put it in gear (running) and watch the driveshaft, look for any run-out the entire length. Any wobble, could be causing the problem. The technical way would be to find out what "frequency" the vib is, everthing, tires, driveline, engine, all have a different frequency level. We have a hand held recorder at work to figure this stuff out.
Following your advice, I raised the rear of the car up and noticed the left rear brake drum scrubbing in one place. It seemed as if the drum was out of round, though I just had them turned. could the rear axle be bend, if so what is the best was to check this? I have access to a dial indicator. on the passenger side with the wheel on there was a noticable wobble at the wheel. I tried my spare and this seemed to mostly go away. the drive shaft was dead on no wobble noticed. Thanks for your advice. Mark
Might be a dumb suggestion this far into it, but make sure you are not overtightening the nuts on the u-joint. 8-15 ft/lbs only. That is just lightly tightened with a wrench. Much more will cause bind and those kinds of noises.
one other point to check is the trans mount. Mine started to vibrate and three different shops thought it was my ujoints that i just replaced. when i replaced the trans mount i found it had worn and shifted right about an inch. now it doesnt vibrate at all.
...and the rear transmission seal, from what i have heard... Not sure how that can contribute to play, but if the mount is bad, you probably need new seals anyway.
maybe they are refering to the ...tailshaft bushing...i had a bad vibe and that is what it was. i think when my u-joint went south it took out the bushing and when i replaced the u-joint i still had the vib....frank...
I have a vibration too and i thank you for all this advice,it looks like i have a busy winter ahead.Derek.
