Spline count on a 12 bolt rear??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Injected68LS1 · 12-11-2003, 01:32 AM

Does anybody know what the spline count is for stock axles from a 68 chevy 1/2 ton. It's a non-posi carrier with 3.73 ratio.

Thanks in advance

lukecp · 12-11-2003, 01:39 AM

I'm thinking its 30 spline....not completely sure though...better wait for a second opinion.

**Red68ShortFleetside** · 12-11-2003, 01:55 AM

Yes, the spline count is 30. I just checked on a set of 72 axles. By the way, 72 axles will work in a 68 rear end, they are just about 0.75 inches longer.

Injected68LS1 · 12-11-2003, 02:11 AM

I thought it was 30 too. So if the 72 axles will work in the older housing, what happens to the extra 0.75"?

**Red68ShortFleetside** · 12-11-2003, 03:06 PM

The extra 0.75 inch length just moves the rear wheels out that much. It also causes the drums to not exactly line up with the shoes. It can be solved by spacing the backing plate out 0.75 inch also. It was easier on my truck since I have disc brakes on the rear. You realize that the drum or rotor has to change also since the 72 axles are 5 bolt.
I originally got into this because I put a complete 72 rear end under my 68 to gain a positraction unit. I thought I could just install my 68 6 bolt axles and rotors so I would not have to change wheels. Wellllll, it kinda works if you do a little cutting and grinding. The 72 axle housings are longer than 68 axle housings. The 68 axles will slide in, but they hit the ends of the 72 housing before they can be pushed in far enough to install the C clips. I cut off about a 0.25 inch from the 72 rear end housing which would allow the 68 axle to slide in far enough to install the C clips ( but I still had to use a couple C clamps to force the axle in far enough). Unfortunately this also usually screws up the axle seal. After fighting with this arrrangement for a couple of years, I finally switched back to my original 68 axle housing, installed the positraction carrier and installed C clip eliminators from Barry Williams. This arrangement has been working well.

Injected68LS1 · 12-11-2003, 07:59 PM

Is this your daily driver? I heard from Mark Williams that their c-clip eliminator isn't suited very well for daily driven cars. How are yours? Any problems with the seals leaking??

**Red68ShortFleetside** · 12-11-2003, 08:21 PM

The 68 used to be my daily driver (daily driver for me was 20,000 miles a year) until about 5 years ago. I quit driving it when the maintenance was consuming all of my spare time.
Anyway, I don't know if I will have problems with the rear wheel bearings, since i just installed the C clip eliminators last month. The bearings that Barry Williams uses are a taper design which look like they will handle the side loads well. I suspect that if the truck is not road raced, it should last quite a while.

12-11-2003, 01:32 AM	#1
Injected68LS1 Registered User Join Date: Jul 2003 Location: So. Cal. Posts: 389	Spline count on a 12 bolt rear??? Does anybody know what the spline count is for stock axles from a 68 chevy 1/2 ton. It's a non-posi carrier with 3.73 ratio. Thanks in advance __________________ 1968 Chev SWB with 1998 Corvette LS1 305hp and 320 ftlb to the wheels (stock engine!) AEM EMS and wideband O2 sensors Bowtie Overdrive's 700R4, stage 3 Baer 4 wheel discs and 20s http://iciclelanding.com/aperture?album=2049&view=album

12-11-2003, 01:39 AM	#2
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	I'm thinking its 30 spline....not completely sure though...better wait for a second opinion. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

12-11-2003, 01:55 AM	#3
Red68ShortFleetside Registered User Join Date: Dec 2003 Location: Iowa City, Iowa Posts: 38	Yes, the spline count is 30. I just checked on a set of 72 axles. By the way, 72 axles will work in a 68 rear end, they are just about 0.75 inches longer. __________________ Ike 68 swb fleetside heavily modified TPI engine. Ford AODE automatic (yes Ford!), 12 bolt 4:11 positraction rear axle, 4 wheel disc brakes, wood dash and LED instrumentation, BMW bucket seats, outside stock except for dark red paint.

12-11-2003, 02:11 AM	#4
Injected68LS1 Registered User Join Date: Jul 2003 Location: So. Cal. Posts: 389	I thought it was 30 too. So if the 72 axles will work in the older housing, what happens to the extra 0.75"? __________________ 1968 Chev SWB with 1998 Corvette LS1 305hp and 320 ftlb to the wheels (stock engine!) AEM EMS and wideband O2 sensors Bowtie Overdrive's 700R4, stage 3 Baer 4 wheel discs and 20s http://iciclelanding.com/aperture?album=2049&view=album

12-11-2003, 03:06 PM	#5
Red68ShortFleetside Registered User Join Date: Dec 2003 Location: Iowa City, Iowa Posts: 38	The extra 0.75 inch length just moves the rear wheels out that much. It also causes the drums to not exactly line up with the shoes. It can be solved by spacing the backing plate out 0.75 inch also. It was easier on my truck since I have disc brakes on the rear. You realize that the drum or rotor has to change also since the 72 axles are 5 bolt. I originally got into this because I put a complete 72 rear end under my 68 to gain a positraction unit. I thought I could just install my 68 6 bolt axles and rotors so I would not have to change wheels. Wellllll, it kinda works if you do a little cutting and grinding. The 72 axle housings are longer than 68 axle housings. The 68 axles will slide in, but they hit the ends of the 72 housing before they can be pushed in far enough to install the C clips. I cut off about a 0.25 inch from the 72 rear end housing which would allow the 68 axle to slide in far enough to install the C clips ( but I still had to use a couple C clamps to force the axle in far enough). Unfortunately this also usually screws up the axle seal. After fighting with this arrrangement for a couple of years, I finally switched back to my original 68 axle housing, installed the positraction carrier and installed C clip eliminators from Barry Williams. This arrangement has been working well. __________________ Ike 68 swb fleetside heavily modified TPI engine. Ford AODE automatic (yes Ford!), 12 bolt 4:11 positraction rear axle, 4 wheel disc brakes, wood dash and LED instrumentation, BMW bucket seats, outside stock except for dark red paint.

12-11-2003, 07:59 PM	#6
Injected68LS1 Registered User Join Date: Jul 2003 Location: So. Cal. Posts: 389	Is this your daily driver? I heard from Mark Williams that their c-clip eliminator isn't suited very well for daily driven cars. How are yours? Any problems with the seals leaking?? __________________ 1968 Chev SWB with 1998 Corvette LS1 305hp and 320 ftlb to the wheels (stock engine!) AEM EMS and wideband O2 sensors Bowtie Overdrive's 700R4, stage 3 Baer 4 wheel discs and 20s http://iciclelanding.com/aperture?album=2049&view=album

12-11-2003, 08:21 PM	#7
Red68ShortFleetside Registered User Join Date: Dec 2003 Location: Iowa City, Iowa Posts: 38	The 68 used to be my daily driver (daily driver for me was 20,000 miles a year) until about 5 years ago. I quit driving it when the maintenance was consuming all of my spare time. Anyway, I don't know if I will have problems with the rear wheel bearings, since i just installed the C clip eliminators last month. The bearings that Barry Williams uses are a taper design which look like they will handle the side loads well. I suspect that if the truck is not road raced, it should last quite a while. __________________ Ike 68 swb fleetside heavily modified TPI engine. Ford AODE automatic (yes Ford!), 12 bolt 4:11 positraction rear axle, 4 wheel disc brakes, wood dash and LED instrumentation, BMW bucket seats, outside stock except for dark red paint.



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