The Great Pumpkin

[68Roadster]

Well after about 4 hours and one broken thumb, the Great Pumpkin is out for a much needed rebuild.
It wasn't as bad as I thought it would be, the only problem being now that it's out, I see all the other stuff I would like to clean up, replace, sand blast, paint, etc.....
Does the rear end have the VIN number on it like the engine and the transmission?? It's pretty rusty right now and I can't see many numbers.

Thanks in advance....

Cee

 

[72Mako]

Stamped on the underside of the rear carrier will be:

Rear axle ratio ex: 3:36 positraction
Name of axle plant ex: Warren axle plant
Assembly date ex: 28th day of the year
Positraction manufacture ex: Eaton Positraction Manufacture

carrier casting date will be on the driver's side of the housing directly above strut arm bracket.

Charles

 

[mike weyman]

mako, are you saying that the gear ratio is written on the casing??good info, i'll have to look. can you change gears , or do you change the whole unit?

 

[cwerve74]

Here is a picture of the loaction for the gear ratio stamping. You are looking at the bottom just infront of where the spring would mount. Just behind the camber strut mount. In this case (hard to see) it is AX 348 E1. It decodes to AX= 3.36 348= don't remember?? and the E1 is Eaton rear on a manual shift car. On the side to the carrier case you will find a casting date like K183 K = November 18 1973.

Picture taken after replacing rear cover.

 

[eants]

The other day I found that the top two ears on my diff were busted off. The bolts that hold the rear-end on are still somewhat attached but I will have to replace the cover here soon.

68roadster, I was wondering where there any special tools needed to remove the pumpkin? Is there anything I should keep in mind when I decide to tackle this?


Thanks in advance

 

[68Roadster]

eants,
Nothing special to getting it out. Removed exhaust (at mid frame to rear only), drive shaft, spring, both half shafts, front cushion mount and then the four bolts that hold the pumpkin to the diff mount. Thought I was going to have to remove the diff crossmember but on mine you can get your hand and a 3/8" socket/ratchet in there to undo the four retaining bolts. Lowered it down on a floor jack, it's heavy, make sure you have it supported while you take those last four bolts out.
You should be able to get away with draining the unit, remove the spring and undo the four bolts and just replace the cover unless you want the whole thing out anyway.

Good luck, if you need any help/pictures while mine is out let me know.

 

[GTR1999]

The broken rear cover is common,it could have happened from a heavy jar like a pot hole. Also common to break when installing the rear spring and not torquing correct. I use the HD Muskegon covers when rebuilding the rear ends to add a little security to the housing. Worth the money to install it when you have it apart.

 

[eants]

68roadster,

Any pictures you have would be great.

It looks like it has been busted for awhile. There area at the break is all rusted so....

Should this be something I make a priority or can I get away with driving it for awhile????

 

[72Mako]

mako, are you saying that the gear ratio is written on the casing??good info, i'll have to look. can you change gears , or do you change the whole unit?

Mike, I don't know what the codes would be for your '75. But on my '72, the first 2 letters indicate the rear ratio and the following are what they translate to:

AX 3:36 ratio
LR 3:36 ratio
AC 4:11 ratio
AB 3.70 ratio
AA 3:55 ratio
AW 3:08 ratio

of course all ratios in '72 were positraction as it had became standard, earlier years could be had sans positraction on some ratios. Charles

 

[68Roadster]

72Mako,
I just brushed off 37 years of dirt and mine has the following:

1AM10 5 67

What does that work out to be?? I was always under the impression it was a 3:36....

eants,
Tell me what you want pictures of and I'll shoot 'em..

 

[68Roadster]

eants,
www.fastcorvette.com has rear end covers for 92.00.....might find them cheaper else where.....

 

[72Mako]

72Mako,
I just brushed off 37 years of dirt and mine has the following:

1AM10 5 67

What does that work out to be?? I was always under the impression it was a 3:36....

eants,
Tell me what you want pictures of and I'll shoot 'em..

In 1968, the AM would indicate a 3:36 ratio, positraction with smallblock engine.

 

[68Roadster]

72,
Thanks for the info.........

Cee