Is this an HO52 and what fluid???

[66 lwb cs]

Hi I was thinking this is an HO52 based on what I have seen on here but wanted to be sure as I some posts on net that the 3/4 ton's may also have recieved the HO72 or is that just for the 4X4's also need to know what fluid it should take as it is leaking from front seal and need to replenish oil and find a new seal hopefully and if anyone knows of or has a set of 3:73's, 3:90's or even 4:10's let me know via pm as I would like to replace the 4:56's that are in it for better cruising. Here is a pic thanks for any help.

[66 lwb cs]

Anyone? Help please.

[SFTorange]

It looks like you have an HO52 to me. It's the same rear end that came in my '66 C20. I can tell you that you'll have some trouble finding anything taller than 4.10 gears for that rear. The tallest that will even fit in the housing are 3.90's and as far as I know they were never sold from the factory with them. Companies used to make them in the aftermarket, but I believe they are discontinued. You can find a third member in the junkyard with some luck that has 4.10's (I did at one point). I've since gotten rid of mine and replaced it with a 12 bolt out of a C-10 which is a really easy swap. The only things that really change to make it work are the panhard bar, u-joint, and the switch to six lug. There should still be parts available locally for the HO72 to make it work for the mean time.

Oh, and I just used standard 80w90 gear oil in mine.

Hope this helps a bit.

[Captainfab]

You would be dang lucky to find a 4.10 3rd member for a HO52. Your best bet in your quest for a taller gear, would be switching to a later model differential. Aren't you wanting to change this truck to a 1/2 ton with the 5x5 wheel bolt pattern anyway?

[66 lwb cs]

Originally Posted by Captainfab

You would be dang lucky to find a 4.10 3rd member for a HO52. Your best bet in your quest for a taller gear, would be switching to a later model differential. Aren't you wanting to change this truck to a 1/2 ton with the 5x5 wheel bolt pattern anyway?

Thanks guys for the info and yes I want to go 5x5 at some point but right now money is super tight for my project so was hoping to avoid the expense of the rear swap since then I have to do the front or run two different wheel and tire combos. I was hoping to get away cheaper for the time being and be able to drive over 55 miles and hour without sounding like I am going to the moon. I am trying to get everything together for power steering implant and I have to replace cab mounts as one is almost all the way through. The truck also hadn't been driven much at all before and after the resto so now that I have been enjoying driving it around every seal on it except the ones in the A/C are now leaking so I have to do the main seals and pan gaskets on the motor as well as the tranny and the rear diff. Still a great truck over all just needs a little tlc on the underside. Thanks for the info need the gear oil to refill pumpkin so I don't burn that up and create another expense.

[Captainfab]

You might check around and see what you can pick up a full floating 14 bolt for. Those can be found with 4.10's and often 3.73's. However that will require some cutting and welding. I have the trailing arm brackets for that swap.

[tincan1966]

The HO52's were the only ones in a 3/4T as to what I've been told. I have a 1970 1T Camper Chassis with the even heavier HO72 rear axle. GRAW is 11,000 and the GVW is 14,ooo on this truck! Problem is hardly anyone has any parts and if you find them, they are EXPENSIVE. I opted for a corporate 14 bolt, so I could finish my disc brake conversion. I now have 13" JB8 disc on front and 12' disc on the rear. BTW the HO72 with 4.11 gears is for sale,nothing wrong, just saved a little weight and wanted 3.73 gear.