Schaggy

Hello everybody,

I'm dropping the differential out of my '72 small block and I'm running into a very strange problem.

I dropped my spring, my control arms and bracket, disconnected my short shafts and driveshaft, put a jack under the diff and disconnected the the single bracket in the front and the two bolts that connect the crossmember to the frame.

For whatever reason, the diff doesn't drop.

Does anybody know what I've missed?

Thanks!

Gordonm

Yes rust. The two bolts that hold the crossmember are stuck. The sombreros are rusted or stuck together. This is a common problem. Either use a long prybar, I have a 6 foot bar I use or use a gear puller. When it pops you will hear a loud bang. Have the rear supported as it weighs in about 100 pounds.

Steve439

Yeah, a really big pry bar!

You need to pry the crossmember down.
It takes a LOT of force.
Do some searching and you'll see lots of advice.
I bought a longer bar a few weeks ago to do some garden work which should work nicely next time I change a diff.
The last time I did one I almost hurt myself.
I must be getting old!

Steve439

Ha, I'm not only old but I type slow...
Gordon has you covered...

Oldguard 7

Yup big pry bar. It will resound with a loud crack when I removed mine back in 04, I thought I broke something.

69'Silver

Shoot some WD in there and let it soak in for a while. Just did this last month

Rally68

My vote is for the 2-jaw puller. Put the 2 crossmember bolts back in about halfway; the puller will bear on the bolt heads and the bolts will keep the diff from falling to the floor when it comes loose.

scrappy76

Good call.

wcsinx

Use a puller not a prybar

A prybar will force the joint off center which is why it takes so much force that way. A puller will yank it straight down.

Schaggy

I just wanted to drop a note to say thanks to everyone for the advice. I picked up a 6" two-arm puller from Harbor Freight and it worked like a breeze!

Thanks everybody!

Dustup7T2

If you get the chance, post some pics so we can follow along. We like to see these projects too.

Good Luck.

Schaggy

I didn't have time to take pics along the way, but here's the final product. I went through the whole rear suspension and added a fiberglass spring:

mrvette

Nobody mentions putting it BACK......slather the parts with RTV, nice coating each....jack into position, bolt er down....

next time it comes apart slick as snot on a doorknob....

Red 69

What I didn't see anyone mention is buying long shoulder bolts to replace the factory bolts, when prying the notoriously stuck sombreros loose. These long shoulder bolts will stop the assembly from falling to the ground, as mentioned. They also help in the reassembly, by guiding the cross member up into position. Remember, the weight of the third member creates a weight off-set and imbalance that can be a challenge to control. Once the sombrero is engaged, the factory bolts can be replaced and torqued to spec. This is a method that made my dis-assembly and assembly go easier. I'm glad you got it out safely, I needed a five foot pry bar to separate one I had done.

You might like to put some heat wrap on your exhaust pipes, to better shield the new composite spring from heat.

Schaggy

I just put down a flattened box, then put a 4x4 on the ground and set the diff with the carrier bracket up on its nose. Worked great!

rugerm44

Im getting ready to go thru the same thing to replace my side yokes.I read in the manual you can pull the diff and leave the cover attached.Its starting to look good after reading this thread.

Schaggy

Yes. It's just the crossmember that's a challenge. The great thing about pulling the diff is that you can have it inspected by a professional (if you're a Bubba like me) and make sure it's square.

Good Luck!