Transmission and rear end ID

[trapper]

I have just purchased a 63 convertable with a NOM 327 and am trying to identify the rest of the components. 4- speed transmission has GM markings 3885010 and differential on lower side reads 080 E1 (i think, very hard to read). Car is an outstanding "Mutt" that deserves more mechanical attention than it has received recently. Help with tranny specs and rear end will help because I have a 62 327 non corvette # block, and not sure where rest of drive train dates to

 

[Tom Bryant]

welcome

Welcome Trapper,
I thought this was going to be easy. Well it won't be too hard I just don't have the right books within reach. Need to go to the archives (closet). Have to leave for work shortly so I'll try to find what you need when I get home.

Tom

 

[Montana]

Trapper

Hello Trapper,

Welcome to the CAC. I bet Tom can find your info. He's one knowledgeableness guy. (New word in honor of our country's president). Sounds like you have a nice ride, come on spring!

Montana

 

[Tom Bryant]

Trapper, I didn't forget you.

I put in about a 15 hour run last nite and just got up. Have to leave in 1/2 hr to work again. :J :J Hoping for a shorter night so I can do some middle of the night research. :L

Tom

 

[trapper]

Thanks for responding- Been spending the last week working at my real job or underneath the car. Changing oil, antifeeze, greasing, spark plugs, replacing hoses etc. Haven't done much of this since the early 80's when one could work on cars without plugging them in or having a degree in emissions. Slow progress do to inexperience and previous owners shortcuts. I am probably the only guy in wisconsin that isn't ticked about the losy weather. Up on jack stands yet so I can't est. tranny and rear end under speed. Can't find anything stamped on tranny and numbers on rear end don't make sense to any thing I've found. Some of this is a pain but it's still my first vette and a long, long time goal and rewarding when you finally figure stuff out. Thanks, Mark (Trappers the dog)

 

[Tom Bryant]

'63 knowledgeableness

Mark,
Let's see what I can find.

Transmission

Most '63s used a Warner Gear 4-speed. '63 used an aluminum case. On the right side of the case is a casting # of T10D1. Next line is "W.G.DIV" Casting date is in the upper center of the rt side of the case. Date is made up of month by letter. "A"= January and so on. Then the day of month and then the last 2 digits of the year.
The year may be omitted on some.

Late in '63 the Muncie transmission started showing up. This '63 trans is unique and differs in many ways from the '64 and newer. There is an exposed area of the machined surface at the lower rear where the side cover attaaches. The assembly code is located there. It is a stamping made up of the letter "P" followed by a date code for month and day.

On the right side will be a casting # of 3831704, the words "PAT. PEND." and General Motors Corp. In '64 the words "U.S. Patent No. 3088336" were added and they will be on all '64 and newer Muncie cases no matter what the casting #.

3885010 may be a newer Muncie if it has the Pat. No. It could be a Super T-10 also. I confined my comments to identifying the '63 transmission main cases as we are only concerned as to if yours is original to your car.

Differential

The rear carrier was used over other years so the best way to ID it is to check the stamped code on the bottom rear of the carrier. There is a 2 letter ratio code followed by the date code for month, day, year. It may take some scraping and brushing to find this.

There are 9 different codes based on ratio, posi or not, and trans. An example of what you are looking for would be: CB 11 29 62. This is a 1963 3.36 positraction manufactured on Thursday, November 29, 1962. Post your code or PM me when you find it and I'll look it up for you.

If I can heip further let me know.

Tom

 

[trapper]

Thanks Tom- I've verified that I have the patent # 3088336 on it so that confirms its 64 or up and has been added on the car, but can you ID the gear ratios from the 3885010? What's a super T-10? That sound good and it would be nice to find out since its NOM it's at least got a cool nickname!
Did some more scraping on the differential and discovered more stamping. I'm positive now that the complete code is AWW 080 E1. This doesn't tie to any codes I have current access to. I show some AW rear ends in the late 60's and early 70's that ties to a 3.08 heavy duty posi., but nothing AWW. The last part, 080 E1, doesn't seem to tie back to your date code. I polished that bottom pretty clean so I don't think any things hinding back there. Is that possibly an a non Vette or aftermarket item? At this point I'm just trying to figure out what's there to replace with proper fluids
I knew this was a NOM car but just didn't appreciate how far up the line that went! Messing with Holley 4150 non original carb tonight - I've not had a carb in my household since a 76 Trans Am that never ran right, so I'm working slow. Thanks so much for your help!!

 

[Tom Bryant]

numbers

Mark,
You definately have a '64 or newer Muncie. See if you can find the date code as I discribed to verify year. There was also a suffix code on the end of the build code to identify usage. They were: A=M20 wide ratio, B= M21 close ratio, C= M22 close ratio Roch Crusher (HD).

The Super T-10 was a Warner 4-speed that showed up in '74 as a heavy duty aluminum case trans. It was offered that year as well as the M20, M21, and M22 Muncies. All 4-speeds from '75 to '81 were Warner Super T-10s.

I feel that your axle code is AW. Many times these codes were mis-stamped or double stamped. AW was a 3.08 posi or HD posi, depending on year. 3.08 wasn't used every year. It skips a couple years and in '70 they used 3 letters (CAW). '68, '69, '71, and '73-'75 used AW. Anyway, I think it is safe to say that it is not a '63 rear end. Should be a positraction if it hasn't been changed. To check get both rear wheels off the ground. When turning one wheel if the other turns the same direction it is posi. If it turns oppisite it isn't.

Go to GM and get their Multi Purpose Diff Lube (part # 1050081) and a bottle of posi additive to condition the clutches. The same lube works in non posi rears too. I hope that is still the right part #. The cans I have in the garage are so old that the lettering is hand painted. :L

Keep me posted on what you find.

Tom

 

[vettefinderjim]

Mark, My source books show maincase #3885010, extension housing #3857584, sidecover # 3884685. These numbers were on all Muncie M-20 wide ratio, M-21 close ratio, and M-22 "Rock Crusher" HD close ratio transmissions for 1966 and 1967 Passanger, Chevelle and Corvette cars.
There should be an assembly date code on the right side of maincase, just in front of extension housing Example would be P7E03. P = Muncie 4 speed,7=year 1967, E= month (May) ( A= Jan, B=Feb etc)03= Day , the third of May.

Both cases were used for close ratio, and wide ratio. Vin#'s of vehicles were also stamped on the transmissions.........if you find one of those we can tell what kind of car it came from......no vin#, it was probable a parts dept. unit.
Hope this helps,
Jim Gessner

 

[trapper]

Wow! We are getting closer! I agree on all # except the extension housing # is 3846426 and the stamping is P1208. There is no suffix code that 59Tom referred to A,B,C,). Even had my 12 year old son look at it. Told him he should start learning this stuff with me. Guess I forgot to mention the middle age short range vision stuff.
I'm guessing but if my diff is AW which includes '71. Might this be a 1971 February 8th? If it matters it's an aluminum case.
Since now I know that I have a 3.08 I can back into gear ratios by driving at a fixed speed and the tach. Idaho Corvette club web page has a calculator that will fill in the rest. I'm pretty sure its a close ratio by the limited amount of driving that I've done.
How does one confirm if its a M21 or M22? With all of the NOM disappointments all the way up the drive train it would be fun to prove it's a Rock Crusher.
With the Holley 4150 carb on the car the HD would make more sense. But when I bought the car in Feb. the battery was not tied down, the expansion tank kind of held in place with nylon lock ties , no radiator bottom bolts, a 2" strip cut from an Italian juice can clamped over the lower hose to stop a leak. Just discovered that the carb bolts all have been stretched. They have been torqed so hard that they have a narrow area that I first thought was due to wear or rust, but the threads are sharp and spread. Never seen that before.

 

[Tom Bryant]

WOW

Must have used a looooong bar on those carb nuts.:s The only M22 I have owned was in a '70 El Camino SS 454/450hp LS6. It is very obvious if you have one. Lots of gear noise due to the reduced angle of the gear cuts. They are not straight cut as is commonly believed but are close to it. I'm not sure on the aluminum rear end. I'm also not at home where I could look it up. :L You are probably right on the date. Thankfully we have Jim here to help now. He has owned more of these things than some of us have even seen. At least you know what year case you have. I have a Muncie under the bench that I am fairly sure was built over the counter and from parts.

Tom

 

[trapper]

As I'm under the car tonight attempting to loosen the magnetic nut installed in the aluminum transmission case I remembered a scientific principal about steel and aluminum in contact. It's a square nut so my sockets don't work, can't get enough leverage on an open wrench, and looks like we have to add to the tool collection. Anyway..
A 3.08 rear end will turn the wheels 3.08 times for every driveshaft revolution, so backwards its the same. When I turn the tire one rev I got between 3 1/4 and 3 1/2 turns. It's not real precise but I think its a 3.38. Is there anything wrong with my logic?
Can any one come up with a logical explanation of why one needs a mag filler plug on an aluminum case?
This was still better than my day at work!!!

 

[vettefinderjim]

I'm Looking???

Well you got me looking. The extension housing # I have shows 3846429 not 3846426. This side cover began in 1964 and ran with two changes up to Feb 1965 production. After that it changed to 3857584 used thru 1969 production.

The AW code is heavy duty Corvette 3:08 ratio. Thats how it started life. If you trully are getting 3 1/4 to 3 1/2 turns the gears could have been changed to 3:36 or 3:55. My guess is the orginal 3:08 is present. At 70 mph you should be turning about 2700rpm with 3;08 and 3000 with a 3:36, and 3200 with 3:55. The only way to really know, is take it apart and count the teeth.

If you pull the trans you can tell if it is a rock crusher from the imput shaft. Tom is correct about the noise. Rock crusher got it's name due to the wine and gear noise. Very common noise on your road corse race tracks.........
Hope this helps.
Jim

 

[VetteGuy66]

Re: numbers

Mark,
M22 close ratio Roch Crusher (HD).

Do you mean roache or rock crusher or maybe both... heh heh

 

[VetteGuy66]

Re: I'm Looking???

Rock crusher got it's name due to the wine and gear noise.

Is that wine a cabernet or chardonney? Remember what we say to Mustang owners: Do not whine, you could have bought a Vette. I am bad, I know, and I applaud your huge history of Vette ownership. Wow!

 

[smitts]

Rear Differntial

Mark,
Let's see what I can find.

Transmission

Most '63s used a Warner Gear 4-speed. '63 used an aluminum case. On the right side of the case is a casting # of T10D1. Next line is "W.G.DIV" Casting date is in the upper center of the rt side of the case. Date is made up of month by letter. "A"= January and so on. Then the day of month and then the last 2 digits of the year.
The year may be omitted on some.

Late in '63 the Muncie transmission started showing up. This '63 trans is unique and differs in many ways from the '64 and newer. There is an exposed area of the machined surface at the lower rear where the side cover attaaches. The assembly code is located there. It is a stamping made up of the letter "P" followed by a date code for month and day.

On the right side will be a casting # of 3831704, the words "PAT. PEND." and General Motors Corp. In '64 the words "U.S. Patent No. 3088336" were added and they will be on all '64 and newer Muncie cases no matter what the casting #.

3885010 may be a newer Muncie if it has the Pat. No. It could be a Super T-10 also. I confined my comments to identifying the '63 transmission main cases as we are only concerned as to if yours is original to your car.

Differential

The rear carrier was used over other years so the best way to ID it is to check the stamped code on the bottom rear of the carrier. There is a 2 letter ratio code followed by the date code for month, day, year. It may take some scraping and brushing to find this.

There are 9 different codes based on ratio, posi or not, and trans. An example of what you are looking for would be: CB 11 29 62. This is a 1963 3.36 positraction manufactured on Thursday, November 29, 1962. Post your code or PM me when you find it and I'll look it up for you.

If I can heip further let me know.

Tom

Do you have a photo of the location of the numbers/code for the rear differential. I'm not sure where these numbers are located.
pgsmith@stny.rr.com

thanks, chris

 

[JohnZ]

Do you have a photo of the location of the numbers/code for the rear differential. I'm not sure where these numbers are located.
pgsmith@stny.rr.com

thanks, chris

The ratio code and assembly date is stamped on the bottom as-cast surface of the differential housing, between the spring retainer plate and the camber strut rod bracket; it'll take some cleaning to see it.

 

[smitts]

Rear Differntial codes

The ratio code and assembly date is stamped on the bottom as-cast surface of the differential housing, between the spring retainer plate and the camber strut rod bracket; it'll take some cleaning to see it.


View attachment 5019

Thanks for photo. I checked it out and yes it did require some cleaning to make it visible. It read CB 3 15 63 and as I understand - this means it is a 336 posi gears built march 15th 1963?

 

[JohnZ]

Thanks for photo. I checked it out and yes it did require some cleaning to make it visible. It read CB 3 15 63 and as I understand - this means it is a 336 posi gears built march 15th 1963?

That's correct.