First off lets correct this, the Hydra-Matic was first offered in the
1954 Chevrolet model year trucks, not before then.
Second, the 1/2 ton trucks, whether Hydra-Matic, 3sp.or 4sp manual, had a rear
transmission support and were enclosed drive shaft up to and including 1954.
Third, all the 3/4 ton AD's had two piece drive shafts with a center support.
Prior to '54 the front drive shaft was enclosed and the rear open.
1954 and later had open drive shafts front and rear. None of the 3/4 ton manual
transmissions, 3sp.or 4sp. had a rear transmission support or cross member.
With months of searching behind me, I've been unable to find anyone who can supply me
with a picture of an original 3/4 ton that had a factory installed Hydra-Matic. So I cannot
say with any confidence whether the 3604 with the Hydra-Matic option had a rear
transmission support and cross member.
I have reason to believe that the 1955 1st. 1/2 ton with factory installed Hydra-Matic
had an open drive shaft. This I have not been able to confirm since I've not been able to
find a stock 1955 1st. 3100 with a factory installed Hydra-Matic to date.
The 1955 1st. 3104 that my Hydra-Matic came out of had been modified over the years
so I have no way of telling if it was factory correct. The transmission case does say it’s a
1955 and it does have an open drive shaft rear housing.
I also cannot confirm whether the 3105 rear transmission mount and cross member are
the same as the 3104. From what little information I've seen, they appear to be the same.
That sound correct Tim or Greg????
Denny Graham
