C1: 1961 T-10 transmission question

[Barbara S.]

I've been reading over the NCRS Information Manual and Judging Guide and would appreciate any thoughtful input on my question concering the transition from a cast iron to aluminum transmission main box for my 4spd Warner T 10.

When did Chevrolet stop using cast iron main cases for the Warner T-10's in favor of the aluminum main cases? Now the NCRS judging book says it was as late as VIN 2,400 cars (mid-October,'60 production cars). In talking with J.T.'s, who does about as many T-10 rebuilds as anyone, I'm told that the earliest aluminum Warner T-10 4spd that they have ever seen was date stamped Nov. 18, 1960. If that's the earliest, then it would move the transition from cast iron to aluminum to early Dec, 1960 cars.

Why is this a big deal to me? I'm switching my transmission and my car was built on Nov 15, 1960. My engine is correct as is my rear end, but my current T10 is date stamped in Feb, '61 and I want the correct dated transmission in my car. Unless someone can suggest otherwise (other than just quoting from the NCRS book), maybe J.T.'s is right and my car (VIN 2809) should be included in pre-aluminum group.

Does anyone know of an aluminum Warner T-10 4sp main box that is dated in October, 1960?

Thanks,
Tony

[Mike M.]

Re: C1: 1961 T-10 transmission question

tony: tha last word in your second paragraph should read 1961 cars, not 1960 cars as a nov 1960 tranny would have been installed in an early 61 vette, not a 1960 vet. anyway, the refernece to vin 2400 61 vet as possibly having a cast iron t-10 main case is correct. i helped write the judging manual and that guesstimate was based on a 61 vette i once owned with vin less than 2400 that had its original t-10 with aluminum case with vin # stamped in case. mike

[Barbara S.]

Re: C1: 1961 T-10 transmission question

Mike. Just so I'm clear, it's my belief that perhaps the 61 cars manufactured in November, 60 also had cast main cases. The judging manual suggests that the switch from cast to aluminum occurred at VIN 2400 or so, but I'm suggesting that perhaps the switch was made in early Dec, '60 cars, which would be approx VIN 3500. I don't think an aluminum tranny dated November 18, '60 would be installed in a car any earlier than Dec 60.

If that's the case, then I don't think 61 model cars made in November, 60 would have aluminum main cases. Maybe the judging manual should be amended to bump the VIN transition from 2400 to about 3500.

alternatively, have you ever seen a Warner T 10 aluminum 4sp main case dated prior to Nov 18, '60?

Your thoughts?
Tony

[Mike E.]

Re: C1: 1961 T-10 transmission question

Tony--
I mean no disrespect when I say this, but Mike clearly said that he personally owned an aluminum-case 61 in the pre-2400 range, yet you want to disregard that, go with what Piper said, and put a cast iron case one in your 61.
Could your car have come with a cast iron case T-10?--possibly. It wasn't like one day in the plant, they said "no more cast-iron case T-10's". They used whatever was there and closest to the door. Could our wording in the manual (and I've chaired three 61-62 revisions, so I can suggest we're not perfect) be better? Should we say that the transition between cast iron and aluminum began prior to 2400, but we don't know when it ended? Possibly.
However, I'm always uncomfortable when one is "building" a part for a car, and strongly advocates that it is correct. If yours had the original in the car, and we studied and documented that, that's a whole different story. But just because one rebuilder hasn't redone one earlier than a specific date doesn't mean that we're going to adapt the judging manual to that.
Regards,
Mike Ernst

[Barbara S.]

Re: C1: 1961 T-10 transmission question

Mike. I'm not disregarding the other Mike's previous answer. Some people just want the "right answer" and others want to understand why it is the answer. I fall into the latter category.

From what I can gather from both answers, it would seem that both cast and aluminum trannys were originally installed in Oct/Nov '60 in the production of '61 cars. I am curious when the use of cast trannys finally ended. The judging guide doesn't really suggest when that occurred.
Regards,
Tony

[Mike E.]

Re: C1: 1961 T-10 transmission question

Tony--
You're right about that--and that reason it soesn't is that we would rather not put something in unless we're pretty certain--and on that, we're not certain!
Mike