Lost the rear end this weekend - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Travis Byrne · 11-05-2002, 06:37 AM

Hello all, I have lost the rear end in my 72 chevy half ton. I found some teath, they look like they are from a spider gear. You can also see where the pinion gear is rubbing the carrier. My question is how hard is it to change the carries and the pinion gear. I think my axels an all should be ok. Do I need to do any shimming or anything? Thanks Travis.

Travis Byrne · 11-05-2002, 06:38 AM

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hanssolo · 11-05-2002, 12:44 PM

Sorry about your diff. dude. If your ring and pinion are still good you can get a spider gear kit from U.S. Gear or Richmond that uses heavy duty strength parts. This will make a 12 bolt very strong as the little gears, cup shims and spacer bar are the weak point in a 12 bolt. Hows the teeth on the ring and pinion? Any chewing?

Travis Byrne · 11-05-2002, 03:10 PM

I can't tell for sure if the pinion and ring gear are ok. After I found what was wrong I drove it to my Da's house to actualy work on it. I figured on changing out the whole carier and pinion gear. I figure the way it sounded the parts were not any good any more. the pinion had already left marks on the carir and it had only been driven less than a mile. I drove it almost 10 to my parents place. How much does the spider gear kit cost? How hard id it to install?

hanssolo · 11-05-2002, 09:34 PM

It was in a Jeg's catalog. I don't have one right now. If I remember right it was somewhere around $125. It is'nt difficult to install- unless its your first time in a differential. But you may want to take this time to rebuild the whole unit. That way you can get your ideal gear ratio.

*Piston* · 11-05-2002, 09:45 PM

Replacing the spider gears is very simple.. but like it or not your going deeper lol. Ring and pinion is nothing to take lightly... If you havent done this before and dont feel comfortable with it, have a reputable shop do it for you! You'll need a pinion depth gauge, backlash check (dial indicator), setting bearing preload, getting the correct contact pattern on the gear's. Any one of those readings/measurements can ruin your new gears.

Of course you'll also be replacing all bearings, including axle bearings. Everything in there has been running gear oil with metal!

Sorry to hear about the rear-end. that does suck indeed.

hllblly1972gmc · 11-06-2002, 12:33 AM

Being that the pinion gear rubbed, that bearing is shot. personally i would replace both ring and pinion. You do have to shim to set preload on the bearings. On a 12 bolt, you can shim without buying the dial indicators. Just shim until you have the proper gear mesh using paint to see you engagement marks. Also your carrier and axles should be ok. If the pinion gear made any sharp edges in the carrier, just smooth them with a die grinder or file.

Fred T · 11-06-2002, 01:25 AM

First tool you'll need is the factory shop manual. It does a pretty good job of spelling out what to do.

11-05-2002, 06:37 AM	#1
Travis Byrne Registered User Join Date: Jul 2002 Location: Corydon, IN Posts: 82	Lost the rear end this weekend Hello all, I have lost the rear end in my 72 chevy half ton. I found some teath, they look like they are from a spider gear. You can also see where the pinion gear is rubbing the carrier. My question is how hard is it to change the carries and the pinion gear. I think my axels an all should be ok. Do I need to do any shimming or anything? Thanks Travis. __________________ 1972 Custom/10 Longbed In the works

11-05-2002, 06:38 AM	#2
Travis Byrne Registered User Join Date: Jul 2002 Location: Corydon, IN Posts: 82	I forgot it is a12 bolt . __________________ 1972 Custom/10 Longbed In the works

11-05-2002, 12:44 PM	#3
hanssolo Registered User Join Date: Sep 2001 Location: central Ill. USA Posts: 447	Sorry about your diff. dude. If your ring and pinion are still good you can get a spider gear kit from U.S. Gear or Richmond that uses heavy duty strength parts. This will make a 12 bolt very strong as the little gears, cup shims and spacer bar are the weak point in a 12 bolt. Hows the teeth on the ring and pinion? Any chewing? __________________ 69 C10 longbed: 357c.i. /TH400/3.73s/AC/ beige primer/saving $ for paint ______________________________

11-05-2002, 03:10 PM	#4
Travis Byrne Registered User Join Date: Jul 2002 Location: Corydon, IN Posts: 82	I can't tell for sure if the pinion and ring gear are ok. After I found what was wrong I drove it to my Da's house to actualy work on it. I figured on changing out the whole carier and pinion gear. I figure the way it sounded the parts were not any good any more. the pinion had already left marks on the carir and it had only been driven less than a mile. I drove it almost 10 to my parents place. How much does the spider gear kit cost? How hard id it to install? __________________ 1972 Custom/10 Longbed In the works

11-05-2002, 09:34 PM	#5
hanssolo Registered User Join Date: Sep 2001 Location: central Ill. USA Posts: 447	It was in a Jeg's catalog. I don't have one right now. If I remember right it was somewhere around $125. It is'nt difficult to install- unless its your first time in a differential. But you may want to take this time to rebuild the whole unit. That way you can get your ideal gear ratio. __________________ 69 C10 longbed: 357c.i. /TH400/3.73s/AC/ beige primer/saving $ for paint ______________________________

11-05-2002, 09:45 PM	#6
Piston Account Suspended Join Date: Oct 2002 Location: Olathe, KS Posts: 2,301	Replacing the spider gears is very simple.. but like it or not your going deeper lol. Ring and pinion is nothing to take lightly... If you havent done this before and dont feel comfortable with it, have a reputable shop do it for you! You'll need a pinion depth gauge, backlash check (dial indicator), setting bearing preload, getting the correct contact pattern on the gear's. Any one of those readings/measurements can ruin your new gears. Of course you'll also be replacing all bearings, including axle bearings. Everything in there has been running gear oil with metal! Sorry to hear about the rear-end. that does suck indeed.

11-06-2002, 12:33 AM	#7
hllblly1972gmc Registered User Join Date: Nov 2002 Location: colorado Posts: 16	Being that the pinion gear rubbed, that bearing is shot. personally i would replace both ring and pinion. You do have to shim to set preload on the bearings. On a 12 bolt, you can shim without buying the dial indicators. Just shim until you have the proper gear mesh using paint to see you engagement marks. Also your carrier and axles should be ok. If the pinion gear made any sharp edges in the carrier, just smooth them with a die grinder or file.

11-06-2002, 01:25 AM	#8
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	First tool you'll need is the factory shop manual. It does a pretty good job of spelling out what to do. __________________ Fred There is no such thing as too much cam...just not enough engine.



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