The Stovebolt Site Forums The Shop Area The Tool Chest Differential Holding Fixture

Does anyone know what the Kent-Moore "J" number is for the HO52 differential holding fixture? I found a J-6177, but didn't measure my HO52 before ordering it. The J-6177 is obviously for much larger differentials. If I had the means to make an attachment, I could simply build something that added on to the J-6177, but I do not have that option, and have to return the item. So, I am asking for the "J" number if someone knows it. Thanks.

I just browsed through the 48-51 Truck Shop manual and didn't see a mention of a differential holding fixture for any rear differential up through the 2-speeds for big bolts. The figures just show the differential clamped in a vise. Also nothing in the special tools listing. But the 55.2 truck shop manual does show a differential carrier holding fixture J-3289 used on a 1/2 ton differential. The difference must be with the torque tube axle used in the earlier trucks, the torque tube or carrier just gets clamped in a vise.

Out of curiosity, I checked eBay listings and found similar but not exact fixtures when I searched for J-3289. Most look different than what's pictured in the shop manual. AND they were all e$$pensive. I had a thought that you might adapt an engine stand to hold the differential for working on it. Here's what I did for working on and painting my transmission.

The J-3289 is maybe what I am looking for. And you're right, they are pricey on ebay.

If that's not it, I wonder if there is one for the HO52? I saw a video a few years ago, can't find it now, of a guy servicing a 3rd member from a 56 chevy or something similar, so I thought there may be a holding fixture for the HO52. The J-6177 is about 4 inches wider than what I need for the HO52 3rd member.

I was going to somehow adapt the holding fixture to be used with an engine stand. Either that or construct a pipe holder into a bench to hold the fixture in place. I also bought a transmission holding fixture, so the anything adapted for the differential holder can also be used for the transmission holder.

Shane - A little searching for more details about the Kent Moore J-3289 can be seen below in the extract pic from a Kent Moore Fall 1974 Catalog.

If you're wanting to stick with the original Kent Moore tools, you need the J-3289-01 differential holder kit, which is supposed to include the J-3289-20 mount, as well as the J-8622 fixture adapter kit (not originally part of the J-3289-01 kit). On the fixture adapter kit, you may be able to just fabricate some plates to take the place of the adapter plates to hold your HO52 differential.

Wish you luck in finding what you need.

Here's a pic of the J-3289 from the 55.2 Truck Service Manual. A little clearer than Dan's catalog pic.

I still think that an engine stand, with the moveable brackets, could be used as-is to bolt a differential housing in place. As I mentioned earlier, the earlier service manual showed the housing clamped in a vice, even the bigger differentials.

Dan, thanks for that info, it matches what Kevin shared. I wonder if the J-8622 is to rest the housing on? The mount is what I need to fabricate something to be used on a bench or engine stand.

I see what you're getting at, bolting it to an engine stand without the holding tool. That may work just fine. I'll have to check it out.

From what I could tell, the J-8622 are the two side plates and hardware that attached to the main mount shown in Kevin's picture. Below are some pictures from that same Shop Manual showing the holder in use for various differential work.

That is what I will be doing, taking it down to clean it up, replace what needs to be replaced, and reassemble.

It's been sitting outside, so I have lots of cleaning to do.