Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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LockDoc |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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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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Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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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 |
Re: Rear Axle Ratio Charts For 1967 - 1972 GM Trucks
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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
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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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