1970 12 bolt axle length? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70 SUB · 08-22-2002, 05:15 PM

I am going to buy new axles from moser but I need the length of the axle. Has any one already done this? It's off a 1970 suburban with coil spring rear end. I would like to buy the axles without taking her off the road for so long.
Thanks

6869704X4 · 08-23-2002, 05:48 PM

You might have to bite the bullet and yank yours out and measure them then put them back and drive it untill you get your new ones. Most it will cost you is some gear lube, gaskets and a couple of hours.
Only way to be sure.

**MikeB** · 08-26-2002, 05:06 PM

All I know is that the 69/70 axles are shorter than 71/72 axles. Have you asked GMC Paul if he knows the length?

BadHabit · 08-27-2002, 02:28 AM

When I converted my 70 1/2 ton to 5 lug I bought used axles out of a 76 chevy 1/2 ton. So long as you know for a fact that your axle is a 70 model it won't be problem because 69 and back used different spider gears in the diff. What was different about the spiders was the spline count. Bye the way, 71 and 72 axles WILL slide right in to a 70 diff. I tried that for myself once a few years ago. If you want to retain the 6 lugs you can get a set of axles out of any 12 bolt 1/2 ton 4 wheel drive rear up till around the mid-eighties. Also if you want beefy rear brakes you can go with the later model 3" wide setups. You will need the backing plates and associated stuff off of a donor axle for this swap. If it is hard to believe just give Randy's ring and Pinion a call and ask them if the part number is the same for a 71/72 axle as it is for a 76 axle. Remember that 6 lugs remained standard on all Chevy/GMC 1/2 ton 4x4 trucks thru 87, however, the 12 bolt rear phased out slightly before that. Happy hunting...been there, done that.

Bamm · 08-27-2002, 05:10 PM

Measure!!!!!!! BadHabit is partially right. 71 & 72 axles will slide right into SOME '70 rears, but not all. I know, I now own a 3.73 posi '70 rear that is the same length as the 68-9's. I have since learned from multiple sources that some of the "early" '70 trucks came with the '68-9 width rears. The time it takes you to pull the axles will pale in comparison if you order the wrong length by mistake................JB

*Fast68Chevy* · 09-08-2002, 03:03 AM

70-up all 12 bolt are same length shafts, even with wider brakes in 77-79 big 10 models,.

spiders are no different in any of them, only except in the light duty van 12 bolt some years particularly 74, there were five different rates 12 bolts,
from 2400 to 3600lbs
pickups and blazers and burbs use the heaviest ones

70-up are 31 3/16" overall length, not including wheel studs

4x4 and 2wd are all same shafts cept for studs

Bamm · 09-08-2002, 09:58 PM

You need to measure. Period. I know that a lot of guys here know a lot of things about these trucks, but I know that '70 rears came two different lengths. I bought a 3.73 posi rear out of a '70 truck and the axles were a different length than the '72 rear axles in my truck now. This was an original rear out of an early '70 truck. Suburbans, i'm not so sure about, but I know if it was me I would rather measure than take someone's word for it and buy new axles and they be the wrong length. Don't get me wrong, I value everyone's advice on this board, but I like to be sure about things when there's that much money on the line...... Good Luck........JB

08-22-2002, 05:15 PM	#1
70 SUB Registered User Join Date: May 2002 Location: Va Beach, VA, USA Posts: 31	1970 12 bolt axle length? I am going to buy new axles from moser but I need the length of the axle. Has any one already done this? It's off a 1970 suburban with coil spring rear end. I would like to buy the axles without taking her off the road for so long. Thanks

08-23-2002, 05:48 PM	#2
6869704X4 Registered User Join Date: Jul 2002 Location: SE NM Posts: 769	You might have to bite the bullet and yank yours out and measure them then put them back and drive it untill you get your new ones. Most it will cost you is some gear lube, gaskets and a couple of hours. Only way to be sure. __________________ The more I learn about women, the more I love my truck.

08-26-2002, 05:06 PM	#3
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,597	All I know is that the 69/70 axles are shorter than 71/72 axles. Have you asked GMC Paul if he knows the length? __________________ Mike 1969 C10 LWB -- owned for 35 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!

08-27-2002, 02:28 AM	#4
BadHabit Registered User Join Date: Aug 2002 Posts: 11	Axles... When I converted my 70 1/2 ton to 5 lug I bought used axles out of a 76 chevy 1/2 ton. So long as you know for a fact that your axle is a 70 model it won't be problem because 69 and back used different spider gears in the diff. What was different about the spiders was the spline count. Bye the way, 71 and 72 axles WILL slide right in to a 70 diff. I tried that for myself once a few years ago. If you want to retain the 6 lugs you can get a set of axles out of any 12 bolt 1/2 ton 4 wheel drive rear up till around the mid-eighties. Also if you want beefy rear brakes you can go with the later model 3" wide setups. You will need the backing plates and associated stuff off of a donor axle for this swap. If it is hard to believe just give Randy's ring and Pinion a call and ask them if the part number is the same for a 71/72 axle as it is for a 76 axle. Remember that 6 lugs remained standard on all Chevy/GMC 1/2 ton 4x4 trucks thru 87, however, the 12 bolt rear phased out slightly before that. Happy hunting...been there, done that. __________________ 70 Chevy SWB 4x4 350/350/203. 02 Honda VTX. 98 Honda XR400. 88 Honda prelude Si 4WS. 99 Nissan Maxima SE. & one spunky little Jack Russel.

08-27-2002, 05:10 PM	#5
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Measure!!!!!!! BadHabit is partially right. 71 & 72 axles will slide right into SOME '70 rears, but not all. I know, I now own a 3.73 posi '70 rear that is the same length as the 68-9's. I have since learned from multiple sources that some of the "early" '70 trucks came with the '68-9 width rears. The time it takes you to pull the axles will pale in comparison if you order the wrong length by mistake................JB __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

09-08-2002, 03:03 AM	#6
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	70-up all 12 bolt are same length shafts, even with wider brakes in 77-79 big 10 models,. spiders are no different in any of them, only except in the light duty van 12 bolt some years particularly 74, there were five different rates 12 bolts, from 2400 to 3600lbs pickups and blazers and burbs use the heaviest ones 70-up are 31 3/16" overall length, not including wheel studs 4x4 and 2wd are all same shafts cept for studs

09-08-2002, 09:58 PM	#7
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	You need to measure. Period. I know that a lot of guys here know a lot of things about these trucks, but I know that '70 rears came two different lengths. I bought a 3.73 posi rear out of a '70 truck and the axles were a different length than the '72 rear axles in my truck now. This was an original rear out of an early '70 truck. Suburbans, i'm not so sure about, but I know if it was me I would rather measure than take someone's word for it and buy new axles and they be the wrong length. Don't get me wrong, I value everyone's advice on this board, but I like to be sure about things when there's that much money on the line...... Good Luck........JB __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

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