1963 Powerglide Option

[Jeff B.]

Re: 1963 Powerglide Option

I had the same problem with a 1967 300hp Powerglide. Turned out to be the rubber cushion sandwiched between the rear end housing forward extension and the frame. The cushion had deteriorated to practically nothing. Car did have over 100k miles, so maybe justified. After replacing cushion, everything returned to as-new performance.

[Andreas S.]

Re: 1963 Powerglide Option

I had the same problem with a 1967 300hp Powerglide. Turned out to be the rubber cushion sandwiched between the rear end housing forward extension and the frame. The cushion had deteriorated to practically nothing. Car did have over 100k miles, so maybe justified. After replacing cushion, everything returned to as-new performance.

Thanks Jeff, I'm going to have the complete drive line and rear assembly fully inspected again as Duke suggested.

[Joe L.]

Re: 1963 Powerglide Option

I had the same problem with a 1967 300hp Powerglide. Turned out to be the rubber cushion sandwiched between the rear end housing forward extension and the frame. The cushion had deteriorated to practically nothing. Car did have over 100k miles, so maybe justified. After replacing cushion, everything returned to as-new performance.

Jeff and Andreas-------


Another thing that can cause this problem on C2 Corvettes regardless of transmission is elongation of the holes on the side of the forward differential bracket. On a 1963, these are the holes for the 4 short bolts which thread into the carrier housing. Over time, these holes in the bracket elongate and result in a "clunking" sound when the driveshaft first turns after a stop. GM improved the bracket later in C2 production by adding welded-on thick washers to one pair of the holes. This helped but it did not really solve the problem. The real fix came for the 1969 model year when thick plates were welded to the sides of the bracket with the holes drilled through.