Canadian 12 Bolt Decoding I was wondering if anyone could help decode the 12 Bolt rear axle in my 1969 Skylark Custom. Here are the numbers I found LE 0321K Not sure if it is a c-clip setup yet. I know its currently an open rear,... Will be installing 3.91 gears and a posi carrier. It will have to take the punishment of 600 hp and 600+TQ, with a 4000 rpm stall, so I need new strong pieces. I have a TA aluminum cover on order along with no hop traction bars. Which is a stronger carrier, Eaton or Auburn? I heard there was a new worm gear carrier out there thats bullet proof. Not sure of the name though. Any suggestions for the setup would be greatly appreciated. Thanks in advance.
Graham I can help you a bit but you have the same problem that I ran into decoding a Canadian built GS rear. 03-third month 21-day of month K-GM of Canada The problem comes in with the LE designation. I can't find anything that matches that or the LG that was on my Canadian 12 bolt. Turns out that we just took the gears out and it was a open carrier with 3.31 gears. As far as the aftermarket posi unit I think you'll find that most people say that the Eaton is the stronger of the two. My brother has been talking with some rear end shops and thats been the general opinion. The worm gear unit is the Truetrac from www.detroitlocker.com and that is a pretty stout unit as well. Also with that kind of HP you'll probably want to get rid of those c-clips as well. Either by using c-clip eliminators or by having bolt on ends welded to the end of your axle tubes.
Todd, Thanks. What a mystery... My chassis service manual does not list any data either. Maybe someone else might chime in here and lend some insight on these 12 Bolt code issues. Here is also some good info on the 10bolts: http://www.442.com/oldsfaq/ofdif.htm#DIF Differential Codes 12 Bolt TrueTrac Build Up: http://chevyhiperformance.com/techarticles/0508ch_trac/
Canadian 12 Bolt Codes Todd, Here is some interesting information I dug up at a local dealership. It lists your LG 3:31 code. But it still dosent have my darn LE code.... hmmm
Cool Graham. It's pretty tough digging up info on the Canuck GS'. Weird though how yours isn't listed. Is it a clear stamp because I've heard of the stampings being poor to the point that they are hard to read.
Todd, I will post a pic of the code shortly. Here are 2 pics that are clearer on the Canadian 12 Bolts
1966-1967 Axle Codes Kinda getting off topic for a second here but thought people might appreciate the info.
Yep.. That's definately clear enough to see. I guess we'll find out when you take the diff cover off.
You wanna hear something weird? My axle has the LB code, ('68 2.93) . I have a 69 though. And when I pulled the cover and counted the teeth, it's a 3.07. Which would be correct for the Canadian 12 bolt, which is what I have. So my tube should have an "LD" stamped on it, not an "LB". Just goes to show you the "quality control" back then.
Yea, I agree Ken. I will pull the cover and post what I found. Bet mine is a strike"o" as in typo. :spank: In the meantime I ordered a new Eaton 3 series posi carrier $343, 3:90 Gears $211, Complete overhaul kit $140. From www.markwilliams.com. Way better pricing than I could get up here. :grin:
Hey Graham, what was your original ratio? I know that the lower numerical ratios you are limited sometimes as to what you can install. For the 2 series and low numerical 3 series I've always understood that you can only go as hi as mid 3's or something. Did you confirm all that before buying?
I know if you go with the 4 series Eaton you can go down to 3.73 gears for it. If you get the 3 series it looks like you can go up to 4.10 You are right though Ken. It used to be where the cut-off was cut and dry but now they are making some of the same gearsets for both carriers.
Ken & Todd, Brian at Mark Williams explained that I could go as high as 3:90's with the 3 series carrier. On the same token he explained that one could order as low as 3:73's on the 4 series carrier. I really appreciate you guys asking these kinds of questions, to possibly save me some time, money and grief. I'm kinda new to the rear end and gearing game. Brian was adimant(sp?) the 3:90 on the 3 series carrier combo would work fine. I was glad to hear that because I was under the impression I'd be stuck with the 4 series carrier for that 3:90 ratio. Will have them make me some 30 spline axles and use the C-Clip eliminator Kit. This was my choice for that gear: I'm planning to run a 30" tire with the 3:90's which should get me through the traps at around 58-5900 rpm max. Launching with a 9.5" tight 4000 stall converter should utilize the 614lbs TQ @ 4500rpm well. My max horsepower is 601 @ 5500rpm, hence max 6000 rpm redline. This 464 has an almost unbelievable FLAT torque curve. I'm running the TA 413 Cam, possibly the highest HP ever made from that cam but its all in those TA Stage 1 Heads. Level 4 race port c/w 2.26" intake & 1.88" exhaust valves. This is what I calculate for a sea level near perfect run: 3700LB car/600HP/30" tire/3:90 gears/5500rpm(not including 200-300rpm slippage on converter thru traps) = 10.33@128mph o No: This will be a 40/60 street/strip machine. If anyone has more to add please speak up.
Hey Graham check Ebay for the complete 12 bolt set up some of the places sell the kit for a decent price
