Diff Swap

[Merle Coggins]

Well, I got my diffential swapped out today. Earlier this year I did some horse tradin' with Normspeed for a 3.73 diff out of his parts car. Today I had a chance to install it, and it was a piece of cake.

For one, it's so easy when there's no body in the way. You don't have to do everything from underneath.

The main difference I can see between the car diff's and truck diff's is that the truck diff has 4 spider gears whereas the car diff only has 2. The evidence is in the open diff carrier on the car diff.

Truck diff

Car diff ( I don't remember exactly what it came out of)

Everything went perfectly. Even the axle splines were the same. Both the replacement diff and the original use the 16 spline axle shafts. No need to change anything. The only snag I ran across was my own fault. I forgot to bring along my new plug sockets, so I had to come up with a make-shift tool to remove the drain plug. As some of you know, you need a 5/16" male square drive to remove the drain plug. I have the proper tool for the job, but it was at home in my garage while I was 18 miles away at the shop. So, after some scrounging, I found that a 1/8" pipe plug is the perfect size. I clamped it in a Vice-Grip and got the job done.

The only other difficulty I had, I knew about ahead of time. With no body on the chassis, the springs won't compress. So with the springs relaxed there isn't enough movement in the driveshaft slip joint to allow it to come clear of the drive flange on the diff. When the springs flex under load the axle moves rearward giving more room. So, I added some weight and solved the problem. Just use what you have handy and all works out fine.

[Dale Uhrich]

what kind of car is the carrier from and is your truck 1/2 or 3/4 ton and does it matter

[Jim Shepard]

For those of us considering such a move, the source car is critical. To Normspeed: what was the source car?

[Merle Coggins]

I checked with Norm. It came out of a '50 Plymouth 3 window Coupe

[Jim Shepard]

Thanks Merle. Now I know what to look for. I'm guessing a Dodge would also work; maybe even a DeSoto...

[Young Ed]

I think the whole DPCD line works except some of the big formal cars. Approxiametly 1940-53. I have swapped ratios in both my coupe and the pickup. Pickup 4.10-3.90 and the car went to a 3.73. One of these days I may swap the car back to 3.90 and install an overdrive

[bkahler]

Merle,

I like your resourcefulness....

I've got a backhoe but the bucket is NEAR that large

Brad

[Merle Coggins]

That bucket aint big, Brad. That's a medium sized one.

[bkahler]

Hmmm, I have a small pond I would like dug at the back of my property. With a bucket that size it shouldn't take more than an hour or so

As they say the only difference between men and boys is the size of their toys..... :D

Brad