'63 one year only clutch housing # 3788421

[Ruud Z.]

I will swap the incorrect Muncie transmission for a correct BW T-10 on my early '63. I already bought the correct clutch housing #3788421 and it is still on it's way to me in Europe. I need to know what the measurement is of the transmission bearing hole. All literature says "identical to later#3858403 except for a smaller transmission bearing hole". It does not give me the size of the hole. I have measured the front bearing retainer and I need to be sure that it will fit the clucht house. I am not sure if the correct bearing retainer is on the transmission. So if anyone knows it pls let me know.
Thanks Ruud

[Bruce B.]

Re: '63 one year only clutch housing # 3788421

On the 421 bellhousing the transmission opening is approxamately 4.175 inches in diameter.
The front bearing retainer on a standard T10 is about 4.675 inches in diameter.

[Joe L.]

Re: '63 one year only clutch housing # 3788421

I will swap the incorrect Muncie transmission for a correct BW T-10 on my early '63. I already bought the correct clutch housing #3788421 and it is still on it's way to me in Europe. I need to know what the measurement is of the transmission bearing hole. All literature says "identical to later#3858403 except for a smaller transmission bearing hole". It does not give me the size of the hole. I have measured the front bearing retainer and I need to be sure that it will fit the clucht house. I am not sure if the correct bearing retainer is on the transmission. So if anyone knows it pls let me know.
Thanks Ruud

Ruud------


The correct T-10 will have a main case of casting T-10D-1. This is a difficult-to-find transmission as it was only used for early 1963.

The front bearing retainer is unique to 1963 and that's why the unique-to-1963 GM #3788421 bellhousing must be used with this transmission. The original bearing retainer was aluminum and was, as far as I know, the only aluminum bearing retainer ever used on a Corvette. Problems with this material caused GM to replace it a LONG time ago with a cast iron version for SERVICE. The cast iron version was GM #604932 but it was discontinued quite some time ago.