It appears I am going to replace the differential in my '73 driver.
WDM AH 3.25. NL.
Is there any advantage to another model?
Retailers to avoid?

 

Any 9" case will fit. Make sure you get the right spline count in the new carrier.

Perfect time to add a limited slip.


Quick Performance in Iowa has been great to me. Their prices are reasonable and the service is outstanding.

 

It seems like the more I read the less I know. The 9" case you refer to is the back side?
What exactly am I asking for with "limited slip"? I just spoke with Summit and the man couldn't cross my number. (WDM AH 3.24, 9", NL, 31 spline). I'm not in the parts business but it didn't take me long to figure it out on my own. What I don't want is the local yocal to sell me a piece of junk to make a big profit. I'll pay the bucks but this is the last time my '73 should see a rear end unless it passes me.

 

You have a ford 9" axle. Any 9" 3rd member will bolt in.

Limited slip is just that. Instead of spinning one wheel, you will spin both.

The numbers you got off the little tag are not part numbers. They are ford engineering codes. And They don't mean jack in the aftermarket....


Why do you think you need to replace it in the first place?

 

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Thanks again. I know they are not part numbers. So, after a couple of dozen hauls towing my "69 project, the old '73 started singing in the rear end. I thought it was a wheel bearing, don't have time to work on it so oft to the local mechanic. He drove it and said it was a pinion bearing. He doesn't want to piece repair and have me back the next week. A drop in replacement is next on order. Before he can tell me how many sacks of gold he wants tomorrow, I thought I would do some back ground research and find one better than the Chinese made rear end he will probably offer. After learning what type I have, I run into not knowing the right words for what i'm trying to do. As for "crossing that number" at Summit, if he is selling differentials, he should know a lot more than I about the product and how to read an iD tag rather than send the customer off with his money to look for another salesman.
Way back when I was in some very high dollar sales, we were taught never to let the customer out the door without the product he wants to buy. Send him next door if you want to lose the sale.

 

Replacing the pinion bearings are pretty easy. If nothing else is wrong with it, you'll save a TON of money.

A drop in replacement is going to be at least $600, plus shipping and labor to install it. And that's just for a basic open diff.

You can't get a "Chinese" 9".

Towing a lot? Opt for a lower gear ratio to help with power.

 

I have traded with Moser and Randy's Ring and Pinion on rear end stuff. Both are good.

Whoever you go with it would be good to talk to a knowledgeable sales guy even though both companies have good websites. There are different quality and price gears available for example. The cheapest are often noisy (and probably Chinese). If you have your mechanic source it hopefully he knows or can research a good offering that does not break the bank.

Good Luck.