78 L-82 4sp ?
02-18-2006, 09:48 AM
#1
Le Mans Master
Thread Starter
Member Since: Feb 2006
Location: In The Hardwoods Up North
Posts: 7,419
Likes: 0
Received 1 Like
on
1 Post
78 L-82 4sp ?
I'm looking at a 78 L-82 4sp. members JK78SA and hunt4cleanair said in earlier posts that L-82s came with close ratio m-21s and wide ratio m-20s was wondering if there is a way of identifying which borg warner it would be from markings on the case? .. thanks Ray
02-18-2006, 09:54 AM
#2
Le Mans Master
I'd like to know that answer also, because I have a 79 L-82 4 spd, but I'd be willing to bet more often than not, if the original owner opted for the L-82, then likely they also opted for the close ratio trans. I asked this same question a few weeks ago and never got a good answer.
02-18-2006, 10:14 AM
#3
Melting Slicks
"....A total of 12,739 had the optional L82 engines, 3,385 Corvettes had the M21 four-speed close-ratio gearbox...."
Someone with a Black Book can probably break it down further, build sheet would tell you for sure with RPO codes.
Someone with a Black Book can probably break it down further, build sheet would tell you for sure with RPO codes.
02-18-2006, 10:27 AM
#5
Le Mans Master
Thread Starter
Member Since: Feb 2006
Location: In The Hardwoods Up North
Posts: 7,419
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by C3 4ME
if the original owner opted for the L-82, then likely they also opted for the close ratio trans.
02-18-2006, 10:39 AM
#6
You can request a copy of your original dealers invoice from Allied Vaughn,a first tier supplier for GM....they maintain copies of dealer invoices..cost is $50.....these invoices are available for 77 Corvettes and newer......you need to give them your Vin #....
Rich
Rich
02-18-2006, 10:51 AM
#8
Originally Posted by C3 4ME
Rich, how do you get in touch with Allied Vaughn? I'd be interested in a copy for my 79.
Phone-(419)887-6856
Fax-(419)887-6851
They will send you an invoice request form...just complete form and send back with check....you will receive copy in mail..and as in my case,they also e-mailed a copy.....
Rich
02-18-2006, 02:26 PM
#10
Melting Slicks
My invoice reads on my 78 L82:
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
02-18-2006, 03:29 PM
#11
Originally Posted by karol
My invoice reads on my 78 L82:
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
Gear differences noted below:
Corvette 350 L82/M20 (78) 2.64 1.75 1.34 1.00 2.55 (W)3 Alu. 903 Alu.
ZT Corvette 350 L82/M21 (78) 2.43 1.61 1.23 1.00 2.35 (S) 2 Alu. 903 Alu.
Note that (W) and (S) are ratio codes....
Rich
Last edited by rihwoods; 02-18-2006 at 04:29 PM.
02-18-2006, 07:44 PM
#12
Safety Car
Member Since: Jun 2004
Location: Beecher Illinois
Posts: 4,236
Likes: 0
Received 170 Likes
on
137 Posts
OK, this is from the 78/79 NCRS judging manual. "The most obvious distinction between the two, from an external view, is the shape and configuration of the side cover. The M20(wide)side cover is straight along the bottom and has three shafts extending through it for shift levers. The M21(close)has a curved bottom on the side cover and only has two levers extending through it. The third shaft and lever assembly is located in the case extension."
Hope this helps.
Mike
Hope this helps.
Mike
02-18-2006, 08:03 PM
#13
Le Mans Master
Thread Starter
Member Since: Feb 2006
Location: In The Hardwoods Up North
Posts: 7,419
Likes: 0
Received 1 Like
on
1 Post
Well that makes it easy, thanks Mike and great info on the dealers invoice Rich and thanks to all others who replied.. "what a great board" Ray
Last edited by 78SA; 02-18-2006 at 08:07 PM.
02-19-2006, 04:23 AM
#15
Safety Car
Originally Posted by rihwoods
I have a 78 SA with the M20.....look for the two letter code "HW" followed by a series of numbers...don't know the letter code for the M21..but this should help...
02-19-2006, 04:35 AM
#16
Safety Car
Originally Posted by karol
My invoice reads on my 78 L82:
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
8ym21 four speed close-ratio trans.
The only numbers I could see on the trans is 1304-065-903.
Did not see any letters followed by numbers.
W = supplier
H = Month where A = January
12 = Day of the month
7 = model year
2 = Ratio code
This reads the supplier as Warner assembled Jun 12 77 is a M21 close ratio. The M20 would carry a 1 while a Muncie (MM4) would use an "A" for the ratio code and a slight different code format. If I find a photo...I'll post.
02-19-2006, 08:08 AM
#17
Le Mans Master
Thread Starter
Member Since: Feb 2006
Location: In The Hardwoods Up North
Posts: 7,419
Likes: 0
Received 1 Like
on
1 Post
So it looks like L-82s could have came with 3 different 4 speeds ?
edit: we need to see a build sheet with a M-20
edit: we need to see a build sheet with a M-20
Last edited by 78SA; 02-19-2006 at 08:14 AM.
02-19-2006, 08:14 AM
#18
Le Mans Master
This is great info here guys, keep it coming. I might have to go out in the freezing cold and get down on the freezing cold garage floor today to verify if mine has the close ratio trans or not. Thanks for all the great advice.
02-19-2006, 08:43 AM
#19
Originally Posted by hunt4cleanair
RH...your dealer invoice shows an MM4 four-speed equippd with an L82 in a late 78 built Corvette...quite late in production. Yet here you indicate an M20. You may have added a note below describing the codes and look of it...interesting observation though.
W= Warner Gear
G= July
8= 1978
2= 2nd shift....
Found this...scroll down to "applications"...note "MM4" designations..
http://fiedlerh.home.att.net/BW.htm
This is stamped on the rear end= OJ200
OJ= 3.70:1
Rich
Last edited by rihwoods; 02-19-2006 at 08:57 AM.
02-19-2006, 09:19 AM
#20
Le Mans Master
Thread Starter
Member Since: Feb 2006
Location: In The Hardwoods Up North
Posts: 7,419
Likes: 0
Received 1 Like
on
1 Post
even getting more interesting Rich, according to your link the 3,385 number is total of M-21 and M-20s combined, makes sense .. Ray
edit: so if you have either it makes your car even more rare
edit: so if you have either it makes your car even more rare
Last edited by 78SA; 02-19-2006 at 09:46 AM.