Eaton HO72/HO52 vs. 14 Bolt FF

[kehstr]

Will the G80 locker from a 14 bolt fit in the eaton carrier? They are both 2 piece carriers, just not sure what is on the internals of both of them

[Ironangel]

Heres some good info... http://67-72chevytrucks.com/vboard/s...=536119&page=2 Rather than swapping a G80, why not look for a 14-bolt that has the Detroit Locker in it and just use the locker unit. I believe the Detroit Locker was the only traction device used in the Eaton HO72 & HO52...

[Captainfab]

I have seen several of the Eaton HO52/72's with Detroit Lockers in them. My '66 C20 has one. You might be able to find one from an Eaton.

[bry593]

Here is a YouTube video comparing the HO52 / HO72 carriers of a 4.10 and 5.14 ring gear:
https://www.youtube.com/watch?v=Ol5f...ature=youtu.be
Looks like GM used the same carrier and just thinned out the ring gear.

Here is some discussion of the ring gears:
https://www.youtube.com/watch?v=QCXq...ature=youtu.be

[panel fan]

I suspect the reason for the shortage of 3.90 's was lack of demand as at 60 mph
on 30 in tires there's only a little over 100 rpm difference , hardly worth the effort .

John

[Dave]

John,
Just curious here, is there a GM part number on the ring gear and the nose of of the pinion gear that you can take a pic of?
Lmk thx

[panel fan]

Originally Posted by Dave

John,
Just curious here, is there a GM part number on the ring gear and the nose of of the pinion gear that you can take a pic of?
Lmk thx

I didn't see any but will check again and get back to you if I find some .

John

[Dave]

Originally Posted by panel fan

I didn't see any but will check again and get back to you if I find some .

John

I suspect that you may have a gear set that was made by aftermarket company some time ago to fit into the Eaton 3rds.
Or it could be a GM Canada thing, whereby there were definitely differences in production and equipment.
Having a GM part numbers would clear up any confusion on being original or aftermarket.
Thanks

[Short 3/4]

Originally Posted by Dave

I suspect that you may have a gear set that was made by aftermarket company some time ago to fit into the Eaton 3rds.
Or it could be a GM Canada thing, whereby there were definitely differences in production and equipment.
Having a GM part numbers would clear up any confusion on being original or aftermarket.
Thanks

Read in this forum somewhere (maybe even early in this thread) that the 3.90's were made for the NAPCO 1/2 ton conversions. If you have ever seen one, they are really strange looking as they retain the small 1/2 ton rear, with stock 3.90 gears, but use a modified Eaton for the front, so you have this rear that looks like it came out of a car, then a massive HO52 up front with 6 lug wheels. The 3/4 ton conversions look a lot more normal as the front and rears are both matching Eatons (with the usual 4.56 gears)
So that really makes sense why the 3.90 exists, and is so rare. I don't think anybody has ever found evidence of Chevy offering it as a RPO (I of course could be wrong on that point). NAPCO must have had them custom made for their conversions, and then probably they or the manufacturer had some others they sold as parts for the aftermarket.
This is the best theory on the subject I have come across, and it makes sense to me. What do you all think? Love to hear other opinions on this.
Tom

[jumpsoffrock]

I'm confused.

I have a SRW H072 in my C3500, So do I just get the backing plates from a 14bolt ff and the drums, then take my hub/drum, separate them, put the new drum and my old Eaton Hub together, swap out backing plates and brake parts, and re assemble?


I am confused if I reuse my Eaton hubs, or if I have to do some kind of magic to make the 14 bolt hubs fit my Eaton spindle......

[burnin oil]

From my understanding you are good to go on the SRW axle. I am geared up to try the swap myself in the near future. My donor axle has slip on drums though. Fingers crossed and good luck.

On a side note. Alot of dual rear trucks came from the factory as SRW and are dealer converted to duals. There is an actual RPO code for it. I have one of these trucks in my yard right now but the SPID is missing.

[burnin oil]

I bored a set of hubs out with a good drill. The metal was actually pretty soft. Then I installed the larger lugs. It was all pretty easy. I haven't run them yet. That will be part of my upcoming swap. I want to set up a rear to be able to run duals but be switchable back to SRW eventually. I need a K30 for a few months.

[DOUBLE-DINGO]

That sounds easy enough. Did you use a drill press? I don't have one, but may be able to use someone else's. I'd hate to have lug studs all crooked

This is all going in the '65 C20 in my avatar. I discovered in my parts truck's HO52, that it housed a 4.11 3rd member. I went to move the sometimes daily driven truck the other day to remove the radiator for it to be cleaned and sealed, when my clutch decided to act up. I have been wanting to swap in my SM420 and Ranger OD, but have been enjoying the current setup in the truck. Well, if I have to remove the transmission to work on the clutch, a trans swap is in order, along with an upgrade to the HO52. I swapped in front disc in November 2015, so the braking is much improved, but now for a few more upgrades, and more modern 13 inch brakes will be a nice addition.

[burnin oil]

I used my cordless drill after my good drill finally died. I did chuck them in a vice though. It went quick and they came out straight. I mounted the rims with no problem. I did this with a DRW rear but I am going to decide which axle to put under the K20.