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Discussion Starter #1
I've purchased a 91' Spider with 52,000 miles on it with the knowledge that it would need a little bit of work. For the last six years the car sat in a garage. The major issue it had was a loud clunking noise it would make off the line. I immediately turned to the U-joint, found that to be the issue and replaced it. After replacing that, I am now left with two, very soft clunking noises that I cannot explain when the car accelerates off the line. The drive shaft seems solid to me as does the transmission. The car does not make noise at any other time of the trip. There is a good amount of play in the slip differential that seems like it could produce that noise. I wonder, is that just the spider gears and all is well or have the gears in the differential worn away? Though the sound exists, it does not seem menacing, it is quite melodic... Always off the line, always two knocks, doesn't return until I am back accelerating from 0. Thanks for the input.

13,741 Posts
Welcome to the board, I think we're going to require pictures.
Those of your car will suffice, but really we'll take about anything as long as they don't break forum rules.

Some questions to open with:

1) What is the condition of the rubber doughnut/giubo that ties the transmission to the driveshaft?
(anything but looking like new is usually the wrong answer. cracks, splits, fine crazing or anything that looks like wear including a permanant twist or wrinkles where it might have twisted is a bad sign and warrant its replacement. chunks missing or large cracks near where the bolts pass through is severely dangerous. Like 'get your leg ripped to pieces if it lets go while you're moving' dangerous)

2) Are you positive the u~joints (there are two, and they should have been replaced as a pair) you got were the correct size?
(if done via a local parts counter, the item they handed you fits in there, but in all likelyhood is the wrong size and will begin to thump in short order. Basically most of the counters computers are stuck around the 1970's when it comes to spider parts, and they all say 'fits from 1972~94' even if it doesn't, which in the case of u~joints, and starter motors, they don't)

3) If the driveshaft was taken apart, did the front and rear yokes get indexed correctly?

4) If not taken apart, was the index correct to begin with?
(yoke holes should be in direct line with each other, not off 90, or any other amount of degrees)

5) What is the condition of the driveshaft center carrier bearing?

6) What is the condition of the transmission mount?
(a bad mount will sag the transmission making for driveshaft misalignment, noise when the trans moves under torque load, and some general vibration too if it's bad enough to let the tail section lay down in the mount yoke)

7) How about the engine mounts?
(sagging mounts let the engine move enough to touch things it shouldn't)

8) Do you have a sump guard installed?
(poor mounts or a bent guard can cause the sump to bump the guard and make noise)

Don't try 9, 10 and 11 until 1 has been checked and confirmed safe

9) If you can make the noise from a dead stop, can you also make it by cruising along at around 40mph in 3rd and suddenly dropping off the gas pedal?

10) How about suddenly mashing it?

11) How about suddenly mashing then just as quickly releasing the gas pedal when at a cruise?
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