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Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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here is a pic(if I loaded it right) of the code TAY W175 2 pass. side near the top by brake tee. :chevy:
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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Always a chance one was omitted in the charts or a housing got stamped wrong. If you take the cover off please post up the numbers on the ring gear so there is a record of it in the thread. Thanks, LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
You know I found a thread where a guy had the same thing going on. His was a 3.07 non posi. My front end is 3.07 so I assume I've got the same. If I take the cover off I will be sure to post pics.
Thanks again, Chefk85 |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Good information!
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
I don't know what the C14 is about, but I just looked at my 1967 C10 pickup and there is an HA stamped clear as day on the top side of the passenger tube, pretty close the the pumpkin.
3.73. Super. I was really expecting to see something like a 5.10 or higher based on the fact that I am at 3000 rpms at 65mph. I see a 3.23 rear gear in my future. Anyone know what diameter the ring gear is? I want to say 8.5", but I also know that GM did an 8.625" ring gear as well. Anyone know? |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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I always just figured the C14 was a misprint but I can't prove that one way or the other.... LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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So is this out of a 70 with posi I was told it was out of a blazer with 3.73 gears. It was in the truck when I got it if I remember right we pulled and checked gears but that was 20 yrs ago . I'm sure they could have been changed at some point
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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TPR..... It shows that code for a '70 KE-10, 3.07:1 ratio and a '71 G-10, 3.36:1 ratio. Yep, in 40+ years anything is possible. LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Thanks for posting this but I have a question. My axle code is TDE which just shows 3.07 gears. I thought my rear TDE was posi traction. The rear is not in the truck but if I lock one axle and the yoke in place the other axle will not turn. I thought this meant posi traction.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Thanks this is all great info
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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LockDoc |
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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This might be a stupid question be where exactly do measure from to compare to the stock rear end . I can find a width online and I tried to measure but it's a pain cause it's in the truck.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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I believe it is from flanges where backing plates bolt on. It can be tough when they are still in the truck.... LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Thanks I'm just trying to figure out what it's out of. It seems wide but when I measured today it was pretty close to 60" which makes me wonder why it seems so tight. I was told it was out of a 76 blazer but now I have no clue, it is 6 lug
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
If the truck has posi-traction, would it most likely be listed as an option on the SPID?
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Sorry, I missed this somehow.... Normally they would be an option and listed on the SPID, unless it was added later by someone. The posi rears also had a plastic tag on the fill plug with instructions to use positraction fluid in them. That could be missing though. LockDoc |
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Thats what I thought...wishful thinking I guess. Thanks, |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Thanks guys for showing the axle charts. My Blazer was a RAW, so 3:73 is the axle ratio but what about the numbers stamped to the right of the RAW? Mine is W (then what looks like the upper part of a '3' ) 47
So W 347 ? Thanks. |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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Here is the stamp on my rear axle. RAY for 3.07 open. I'm going to guess it was built on the 251st day of the year, 1st shift.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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Larry, I always thought it would be the 25 day of the 1st month. Don't know for sure. LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Where is Keith Seymore when we need him?:lol:
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Having a RAY code, that's a 1972 KE 10 3.07 open rear end. There's a letter in front of the 251. It's very faint, and looks like a W, which would mean it was built in Warren, MI. 251 would be September 7th (the Julian date, which is the day of the year), and the 1 is the 1st shift.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
My 67 gmc starts with a HA
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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That would be the 3.73 ratio non-posi then. LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Interesting and helpful thread. I'm currently having the rearend in my '68 rebuilt due to many many issues of wear and the cross pin bolt was broken and barely hanging on. I have not sought out the stamped code on the axle housing, but It does have a 3.07, open carrier in it. Along the ring gear are the numbers to confirm the ration, as well as "72" stamped on it. Would this indicate gear possibly transplanted from a 72?
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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I don't think they were date coded but I'm not 100% sure about that. LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Great info ... Thanks :metal:
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
Very good info
Subscribed |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
The charts do indicate what GM offered, but, GM could have offered more ratios to fill the bill more precisely. We had to wait for the square body years for the 3.42 ratio for C 10's and the 3.73 ratio for C 20's.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
I ran the numbers on 2 differentials I have.
One, [TPF 1204w] which I had on my '68 C/10 Stepside, but was damaged in a side impact collision, I thought we pulled off a '69 GMC shortbed fleetside. It had been under my Stepside since the Mid '80s. 3.73 Eaton posi. Chart says 1970, not '69, but who can tell the years by looking at a GMC? The diff I replaced it with [HR 0316w] is [going by the charts] off a '67 P/10 4.11 open. It was a longbed because the 5' handbrake cables didn't work on my 115'' wheelbase C/10. The guy who sold it to me said it came off a '65 or '66 truck. I had it rebuilt with new axles, bearings and 3.73 gears. Still breaking it in. |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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The rear end that was in my truck when I bought it was one of the wider units from a 1970. It had 1970 written on it in yellow paint marker, probably from a wrecking yard. It also measured at the wider width found on 70-72 rear ends. Code stamped on the top of the passenger side axle tube was TDA 11 06 W2, which translates to 1970 3.73 built November 6th. There was also a date code cast into the differential housing that read J 31 9 which translates to October (J) 31st, 1969, which would be appropriate for an early-built 1970 model year.
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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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I purchased a replacement rear end that had the following codes:
HA 05 06 W = 1967-69 3.73 May 6th D 17 8 = April 17th, 1968 The odd thing is that I pulled it out of a 1967 Suburban. I'm guessing it wasn't the original rear end though due to the date code on the differential casting. The cool thing is that it is a reasonable date for my '68 truck that was built in the summer of '68. |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
I have a 1970 leaf-spring 6-lug 3:07 posi, which is "TPO 0422". I decode this as:
What is the meaning of CA vs CE? At first I thought it might be leaf spring rear suspension vs. coil spring rear suspension, but I see the same with K-series so this is ruled out. |
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CE = '' V8 CS = '' L6 CM = '' V6 |
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I just wanted to thank everyone for adding to the thread and say that I'm glad it is still helping people out. LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
This is one awesome thread! So the stamp on my axle is TPR 0612w2 E. It is decoded as either 1970 KE 10 3.07 w/ posi or 1971 G-10 3.36. The gears are 3.07 I can confirm but not with a stamp, rather an engraving where the stamp usual is. This is a 12 bolt unit.
Is the KE designated as 4 wheel drive rear end? Any literature on decoding the casting #s on the outside of rear end? #3896839 My truck is a 1970 k10 swb. Im curious id that 12 bolt was an option on a 1/2 ton truck. The SPID does not say that. Most likely added later by previous owner? |
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E = Eight cylinders. Other designators are -- KS, KM, KA. S = Six cylinders [L6] M = Six cylinders [V6] A = All trucks. Front wheel drive [only] was not an option in this era. All vehicles were primarily rear wheel drive. Front wheel drive assist was actuated by locking the hubs. You have to get out of the truck, stand in the mud, stoop down and twist the levers on each side to engage. The Corporation 12-Bolt differential was standard on all 1/2 tons. [There may have been ''Heavy Half'' variations optioned, but I won't get into that. ] dlyons321 -- Is your truck an automatic? Manual gearshift trucks got 3.73. Automatics got 3.08. 3.36 is an unusual ratio for a pickup. G/10s are 1/2 ton Vans iirc. |
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I understand everything other than the 12 bolt coming standard on 1/2 ton trucks. I have been under the impression that 1/2 ton got 10 bolts and 3/4 ton got the 12 bolts. My truck is automatic and has Dana 44 with 3.07 gears in the front. |
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