gear change out info wanted - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cypress TX 72 · 11-26-2005, 02:28 AM

I have been contiplating replacing the 342's in my 12 bolt, and have seen that jegs has a ring and pinion 411 posi set for sale for 495.00...
I have never done this and don't plan on doing it myself, but can someone tell me if I purchase these gears can they be put into any twelve bolt, or is there much more to it. do I order them specifically for my rear-end or are they all the same??
Thanks for your knowledge.
TS

68Stepbed · 11-26-2005, 02:55 AM

You'll have to make sure they are for a truck 12-bolt. Car and truck diffs are different.

What are you gonna do with the 3.42's? Sell? Keep? I may be interested.

**john** · 11-26-2005, 08:58 PM

Heres a TTT for you. Someone can answer your question, but you might need a different carrier. John

Hunter · 11-26-2005, 09:18 PM

My '70 shortie has a 12 bolt posi with 4.11 (coil springs) and I was thinking of going up in gears to get some hiway speed. LOT easier to swap entire diff's...... I'm in Northern AZ. H.

neonlarry · 11-26-2005, 10:26 PM

As long as you get the Posi carrier that goes with those gears you will be OK. Your center carrier will not take 4.11's.

**N2TRUX** · 11-27-2005, 12:18 AM

Quote:

Originally Posted by neonlarry

As long as you get the Posi carrier that goes with those gears you will be OK. Your center carrier will not take 4.11's.

Like neonlarry said you will need to change your carrier if you want to go to 4.11's. The carrier usually go from 2.xx to 3.73 and 3.xx to 4.xx. I may be off a bit on my numbers but I think you can see what I am saying.

I am curious why you want a 4.11 gear. Assuming you are running a T350 transmission, and a 28" tall tire you should consider a 3.73. That gives you good low end torque and still allows a moderate rpm at highway speeds.

11-26-2005, 02:28 AM	#1
cypress TX 72 Saving one 72 at a time!! Join Date: Sep 2005 Location: Cypress, TX Posts: 261	gear change out info wanted I have been contiplating replacing the 342's in my 12 bolt, and have seen that jegs has a ring and pinion 411 posi set for sale for 495.00... I have never done this and don't plan on doing it myself, but can someone tell me if I purchase these gears can they be put into any twelve bolt, or is there much more to it. do I order them specifically for my rear-end or are they all the same?? Thanks for your knowledge. TS

11-26-2005, 02:55 AM	#2
68Stepbed Registered User Join Date: Mar 2005 Location: 10-Uh-See Posts: 5,609	Re: gear change out info wanted You'll have to make sure they are for a truck 12-bolt. Car and truck diffs are different. What are you gonna do with the 3.42's? Sell? Keep? I may be interested. __________________ Matt 68 C10 stepside, LS1/700R4, TCI Engineering suspension system

11-26-2005, 08:58 PM	#3
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: gear change out info wanted Heres a TTT for you. Someone can answer your question, but you might need a different carrier. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

11-26-2005, 09:18 PM	#4
Hunter Lovin' Arizona Since 1961 Join Date: Jul 2004 Location: Camp Verde, Arizona Posts: 173	Re: gear change out info wanted My '70 shortie has a 12 bolt posi with 4.11 (coil springs) and I was thinking of going up in gears to get some hiway speed. LOT easier to swap entire diff's...... I'm in Northern AZ. H. __________________ "Religion is like a toothbrush: Everybody should have one, but I don't want yours" - Will Rogers

11-26-2005, 10:26 PM	#5
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Re: gear change out info wanted As long as you get the Posi carrier that goes with those gears you will be OK. Your center carrier will not take 4.11's. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI



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