Anyone ever change rear end gears?

[Shvegel]

Hi,
While I am waiting for my body to come back from the metal shop I have decided to continue on with a couple of other projects. One of which is to replace the 4.10 rear axle with a lower(numerical) gear ratio. I purchased a complete rear years ago from a forum member that is a 3.46 ratio but the housing is broken where the boot seals onto it so rather than weld up the housing I would rather just swap the gears from one to the other.

My question is will the 3.46 gears fit into my current 4:10 housing and carrier?

[Garry]

Simple answer is no.
This has been discussed a lot on the forum. e.g.

http://www.sl113.org/forums/index.php?topic=11261.msg76104;topicseen#msg76104

Most of these cars had the 4.08 ratio.  I have not heard of a 4.10 before, you may care to check the number on the rear diff housing.
Garry

[ja17]

Hello Pat,

It would be easier to repair the original housing. The malable casting has a high steel content and welds fine. I just had one repaired.

Some of the V-8 diffs have a larger "pumpkin" with larger ring and pinion gears and cannot be swapped. Just count the number of bolts around the pumpkin and look at the size of both units to confim.

[Garry]

Joe,

Are you saying that some of the V8 pinion gears can be swapped? Or is Pat not talking about a W113 it is going in.  

[Shvegel]

Joe,
The rear is out of a V8. It has cooler lines etc.  I guess It will have to wait until I get the two together. I will have to do a search of my toolbox and see if I still have the bits of the housing.  I have experience swapping gears as well as a pinion depth gauge etc so I'll make a decision then.

The repaired diff looks just like mine broken in the same 2 pieces. Gee...might have to take a TIG course from Lincoln welding here in Cleveland. A friend of mine did the course and one of the instructors welded up my Torque converter. Always wanted to learn anyway.  In case you are wondering yes I am converting to a 5 speed Getrag. 

Garry,
Probably is a 4.08 I am going from memory. I sent the car off for metalwork 4 years ago and the diff is 700 miles away.

[ja17]

Hello Gary,

I believe all the V-8s did use the larger "pumpkin" (diff. casting) which had the larger ring gear and pinion gear. So to use the V-8 gears you would still need to use the laerger V-8 "pumpkin". The V-8 gears do not fit in the 6 cylinder pumpkin. As Pat mentioned, identify the V-8 diff by the oil tube.

Pat, I have some junk diffs out back, if you end up needing the missing section of casting to weld in.

[Shvegel]

Joe,
Believe it of not I remembered tossing the broken bits into the top drawer of my tool box about 7 years ago. I went to look last night and they were right where I thought they were.