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1987 944S CV Joint Noise


Vehicle Information: Year: 1987; Total Mileage: 200,000+km;

On a highway trip in 2003 the car developed a tapping in right hand turns; worse when the tank was filled. Under these conditions, the cv's run at a greater angle, so I cleaned them and re-greased them; there was no sign of galling or dryness. They were just as noisy afterward. By the time I returned home, the problem was worse. I pulled the half-shafts, and swapped them from some of my other 944 cars, 1986 and earlier; they seem similar in overall length. The car has no wheel bearing play, either side, and I am good at finding and measuring it (after pulling the pads back to not contact the rotors.) There was sort of a lot of diff side flange movement, so I swapped in a 1983 trans. I had wanted to know that the trans is fine, so I can sell it (I bought that car bent). The trans seems fine, but the noise is the same. The noise does not appear until the car has been driven a few blocks. There is a normal amount of free play in the steel shaft, axially, so it is not that the balls are being driven to the ends of their grooves. The tapping frequency is a multiple of wheel rotation velocity, dependent on the amount of power being applied (or engine decel) and still dependent on cornering, bends in the road. The diff c/l is about an inch lower than the wheel brg c/l, so the cv's are not past their angular comfort zone.When noisy halfshafts go into another car, they are silent. (I am not sure if the cv angle is less in all the other cars).I checked the 1987 trans, and it still has proper diff side brg preload, the play was just between the side diff gears and the diff housing. the parts all look nice; a light coating of iron on the maget was cleaned off before I put the 1987 trans back together, without doing anything else to it.question 1. The gray drive shaft connector that joins the trans input to the central drive shaft: are they all the same length? mine would not fit. Is this a function of the year? I will measure more carefully next time. One bolt was OK, but the second could not line up with the grooves in the input shaft.question 2: Does this sound like a clear case of cv wear? Should I raise the car to get the diff as high as the wheel brg c/l? Most of my other simmilar cars 'live long' with fairly large angles.Q 3: I have a friend with an early 1985 944. His is noisy when in right hand bends, but he has loose wheel bearings. He is about to buy new wheel brgs. His car is much lower in the rear, so he is being tougher on his cv's. Should he clean/inspect his cv's first?

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