rear end gear replacment

[78-5.3]

how hard is it to replace the gears in a 12 bolts i wanna go 3.73 whats the process of replacing them??

[71meangreenc10]

If you have never done it, I would advise this is not the area to do for fun.

If its an open carrier, its really not that hard IF you have all the special tools.

But if you dont have a dial indicator to set the back lash, the orginal pinion shims to get the pinion depth close, (youll need a tool to set that), paste to check the ring gear pattern, inch pound torque wrench for the pinion pre-load check, and lots of patience, plus a press I wouldnt touch it......

Smitty

[nlped]

^^^ What he said. You can very easily screw up a set of gears if you don't know what your doing. It is a much better idea to just find someone who does this on the side and pay them to do it.

[68 TT]

3.73's in the truck 12-bolt are fairly common. You might be able to pick one up at the local pull it yourself junk yard for less than even the gear install kit costs. At mine it would cost me $85 for any truck / SUV rear axle assembly.

You can also just get the ring & pinion / carrier assembly if you have the tools to get it out for about $27 or hit the main yard and have them get you one off the shelf for $42 if they have one that old.

With this the hardest part is setting the pinion preload when you are putting it back together. It really takes a dial indicator type inch-pound torque wrench to do it right. Not a common tool and not cheap. If you are not going to do this more than once you are better off financially to have a rear end shop replace the bearings and install the gears/carrier into your housing.

You could always go with the 88-98 new body style rear axle assembly that pushes the tires out closer to what the front track width is on the square body trucks. That rear tire inset vs. the front bugs me on our trucks.

[Cherub]

Can you use a 90 91 suburban rear end. i thought they came with 3.73 or 3.42 with posi

[Lo78]

if you put a rear in from newer truck dont you have to do some moving and welding to get things to line up?

[3r!c84]

Originally Posted by Lo78

if you put a rear in from newer truck dont you have to do some moving and welding to get things to line up?

yes

[78-5.3]

up here in MAINE there isnt any pull it yourself places thats what crappy about living in a salt belt LOL

[Matt Man]

that is one of the things i will never do on my truck i always let the pro do it because of the special tools you need.

[Justins76]

Not all that hard a job, just time consuming and requires a few specialized tools. You must have a inch pound dial torque wrench and a dial indicator. Impact wrench helpful too. I found the hardest part was getting the old pinion races out.

[3r!c84]

Originally Posted by Justins76

Not all that hard a job, just time consuming and requires a few specialized tools. You must have a inch pound dial torque wrench and a dial indicator. Impact wrench helpful too. I found the hardest part was getting the old pinion races out.

but i did stay at a holiday inn last night

[68 TT]

Originally Posted by Cherub

Can you use a 90 91 suburban rear end. i thought they came with 3.73 or 3.42 with posi

My old 91 Suburban had 3.08's with the 4L60 trans and it wasn't posi.

[68 TT]

Originally Posted by Lo78

if you put a rear in from newer truck dont you have to do some moving and welding to get things to line up?

Yes you do, glock35ipsc just did it on his project Fred LS swap truck and explains what he did on about post #955.

http://67-72chevytrucks.com/vboard/s...t=fred&page=39

If you don't have the tools to do it then sticking with the truck 12-bolt is the best idea or maybe it is a good excuse to get a good 220-volt MIG welder and a cutting torch setup or plasma cutter.