Rear End Gears

[70chev383]

does anyone know if you can use a ring and pinon from a 67-70 six lug axle in a 71- 72 five lug axle if they are both 12 bolt?

[SS Tim]

Just did this last night. Consider the costs and what you want to do.
http://67-72chevytrucks.com/vboard/s...68&postcount=4

[70chev383]

ive already changed the axle housing I was just wondering about the ring a pinion it self, I have 3:08 from a 71 in mine and I have someone that wants to trade then for 3:73 but they are out of a 69 axle

[SS Tim]

Looks like you still have a question here.
Carrier or gears its still the same answer.
Yes the gears can be transfered over.
They must be reset (reshimmed to the new housing)
You will need some new parts too, at least an install kit.
Bearings might be needed depending on condition.
No better time for a posi too.
Sometimes used gears don't seat well in a different housing like this.
Find a local shop for an estimate and even if they will install used gears.
The axle housing will really need to come out for the change.
Your gear change will spin the engine about 20% faster for a given roadspeed. About the same as shifting out of O/D to direct in many late vehicles.

[70chev383]

thanks that helps a lot
I have put a brand new tremec transmission in it and it has been geared to run at highway speeds with 373 at around 1700rpm
we are both appetences at a local dealership so changing the gears out and setting it all is not a problem
thank you for that information

[SS Tim]

If you are going to the hassle of changing gears and setting them up you might as well do the bearings, a posi and new gears. Old gears develop a wear pattern and with the miles we are talking on these its unlikely you will ever get them quiet (a noisy hypoid gear is not happy). Plus with an O/D you will be spinning at a pretty good clip trying to do 75 in 5th. Not saying it can't be done it has but often there are used gear issues.

[SS Tim]

Training isn't what it used to be. Somehow learning in a dedicated GM drivetrain lab (Burbank for me) seems a lot better than the current "distance learning" via on line videos. Many dealerships do not have people qualifed to set gears. Even those that do don't do it often enough.

[70chev383]

yes i am going to do a posi and a new set of gears at the same time but I drove it a little bit with 3:08 and its way to high and im graduation in about a month and I want it done so I can drive it so the used it a temporary thing

yeah its changed a lot but I've done it a couple times and I know quite a few people that are more then capable