Hi everyone,
I have a '87 D100, Slant Six with an A-833 O.D. 4spd.. Did a first-ever complete clutch replacement which included having the flywheel turned..On the first test drive, the new clutch was engaging smoothly and seemed okay without any noticeable slippage.
I am experiencing vibration cruising at 65 mph and up. None at all below 65. However, at driving at about 50-55, the vibration is present when the clutch is engaged, but momentarily. It doesn't do this below 50. Very weird.
Everything that needed to be marked for reference upon reassembly was marked: driveshaft, flywheel, clutch cover. Even though the new clutch kit included a new cover, i lined up my new cover with my old one, which was marked, and ''transferred'' the mark onto the new cover..

Could it be an over-turned flywheel? or a bad trans input shaft? I hope not.. I was thinking of the input shaft also because me and the helper did had to wiggle the tranny case into position. does it take alot of effort to bend the input shaft?
Has anybody had any similar experience in general?
All help is appreciated

I don't know the english name for the small bearing that is inside the crankshaft for the trans input shaft, but did you change it also?

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Sorry, my english is not very good

Hi Joug, the english name for that would be a pilot bushing (or bush), and it still felt smooth inside with a finger, so I thought Id leave it alone. I had a new one supplied with the clutch kit, which I saved.

Ive rechecked the driveshaft and everything was still tight and reference marks right. I may just have to crawl back under there tomorrow and start taking loose the tranny bolts

"pilot bushing" Thanks

You said that You had some difficulties when assembled tranny back. I thought that maybe that pilot bushing is worn. If it's missing needles (Normally I have seen needle bearings with other cars), it might be that clutch plate is not centering correctly.

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Sorry, my english is not very good

Can we use a pilot busing with needle bearings like other Mopar motors use ?

Yes, 68 and up "big hole" cranks will accept the newer needle bearing pilot bushing.

As for the mystery vibration, it soulds like it is vehicle speed and not RPM related. I would rotate / move the drive shaft into another position, just as a test. Are all the U-joints in good condition? Did the rear U-joint get correctly "seated" in the rear-end yoke, well centered with no crud under the cups?
DD