1 ton ring and pinion swap out....Where to look?

[72freak]

I want to make the dually a little more driver friendly. We are fairly sure its a Eaton H072. 12 bolt. Axle code LY1114
Ring gear says GM 3(7)6 and then 3934643-7

After doing the math we are fairly sure its a 5.14 rear end.

From here and other places I have gathered info that says for this rear I can only get a 5.14, 4.57 or a 410...Is this true? Is there any other options out there?

I am not interested in digging through rears at junkyard looking for something with better suited ring and pinion. Are there any companies that sell or make whay i need? Do any of you have an old rear that has a better gear in it it that might be for sale?

The truck has a granny 4 speed so I can go to a 308, 350 ish or 373. I called out local gear and axle place today and was told " I will have to look into this...my books dont go back that far"?!?!?!?!? I didnt hear back.


Any other recomendations would be apppreciated.

[special-K]

You are right about the ratios available for the HO72,4.10 is the tallest factory ratio.There were 3.90s available in the after market back when these were current rears...very tough to find.The GM 14-bolt rears are a good replacement and you can get 3.73s in those.You`ll need to find a cab 7 chassis one in a simular width to yours.These replaced HO rears in`73.At some point,I believe they got wider at some point.

[jeffspower]

Yep, those are the only 3 ratios. I think at one time someone made a 3.90 ratio.

You could swap in a 14 bolt, one out of a 73- 87 one ton will bolt in- just need to relocate shock mounts, change out park brake cables and maybe a longer driveshaft. 14 bolt OE had 4.56, 4.10, 3.73 and 3.42 ratios. You can get 3.21's aftermarket, as I did for my '88.

[72freak]

OK.............a few phone calls around town today and it does not look like anyone has anything in stock and most dont seem hopefull that I will be able to find anything.

Anyone have any other gear and axle companies they would recomend I call?

[Sinister]

From the research I've done and what I've been told on the Board there is nothing available for the Eaton rear ends.

[69GMCLonghorn]

You need a 700R4 and a Gear Vendors... Do the math... You'll STILL be taching on the freeway... I figure with a DOUBLE O/D like that, you'd be at around 2000 RPM at 60 MPH... So 70 MPH would be more than comfortable... AND you'd have almost unlimited gears in between for if/when you load it up and head over the Rockies!

Of course, the other option is to lift it and put 44" super swampers on it... Those gears will be just about right!

[72freak]

New transmissions with gear vendors overdrive are not in the budget. A set of 44's would be cool but might rub!

My rear axle is about 48" wide.......what would cross over and work?

[capev86]

if you have the 5.14, i will sell you the 4.57 third member out of my 72 burb, cheap, when i get a 4.10. 4.57 isn't too bad if you cruise at 40-50mph and is certainly an improvement over a 5.13. i am replacing the stock 307 with a 406sbc and a 4.10 is plenty for pulling my families 6000lb camper in the short term with the 307. that 4.57 is all the stump puller you will ever need and a single overdrive would make 60mph driving relatively relaxing. you can swap the ring and pinion as a unit and not have to set up shims and stuff if you pull the 3rd member out the front as a unit (kinda like a ford 9 inch).

[BCOWANWHEELS]

i have a 4:10 rear chunk or the whole axle and i,am close to you.
$150.00 and you help me pull it.
bob in kingsport, tn.
423 384 8938

[72freak]

Originally Posted by BCOWANWHEELS

i have a 4:10 rear chunk or the whole axle and i,am close to you.
$150.00 and you help me pull it.
bob in kingsport, tn.
423 384 8938

I think thats going to be the ticket. I will be in Tn. next week. Ill call you tomorrow and see what we can work out. Ill take the entire rear axle to make it quicker, cleaner and easier.

[capev86]

i would go with his offer first as it will be much more highway friendly. just figured i'd make an offer that would help us both out.

[special-K]

There ya go.You can at least cruise 60-65 and stay in the 3,000-3,500 range.55 is real civilized.

[Mike C]

Randy's Ring & Pinion should have the 3.90 gearset in the Yukon brand.

[Sinister]

Originally Posted by Mike C

Randy's Ring & Pinion should have the 3.90 gearset in the Yukon brand.

Got a link?

[72freak]

Originally Posted by Sinister

Got a link?

I looked on their site and found NOTHING for the H072 other than a bearing/gasket kit and I sent an email 3 days ago and have not heard anything. I guess i need to call.

[capev86]

the 4.10 and 3.90 are pretty close in performance. i bet those 3.90 parts are expensive and you'd have to set up the shims and pre-loads and all that stuff, whereas just swapping the whole 3rd member as a unit means it is a quick upgrade. i recommend synthetic gear oil for long life. diff's can get hot, especially when you work them hard (towing, etc) and diff oil is often neglected. i will be running royal purple fluids on my 72 burb.

[special-K]

If you call Randy`s you may find they have things that aren`t listed on the website.Alot of websites only list the most commonly sold models.But,I agree,4.10...3.90...big diff (pun intended).It`s right in the middle between 3.73s.

[72freak]

I called Randys this morning......they use to...but no longer....they have NOTHING.

[kwmech]

I've got a 4.10 center section also. Real heavy though (shipping) asking 150.00

[factorystock]

A 4.10 pumpkin would be a big improvement over the 5.14 and is the simpliest and quickest way to get an extra 10 mph. It is still a mystery why GM used Dana 60's in 3/4 tons, but didn't use Dana 70 axles in their 1 tons.And another mystery, why they didn't use 3.73 ratios in there 3/4 and 1 tons in this era. Ford did offer the 3.73 Dana 60 and 3.73 Dana 70 in there 3/4 and 1 tons.

[72freak]

Originally Posted by kwmech

I've got a 4.10 center section also. Real heavy though (shipping) asking 150.00

Message sent

[72freak]

Ok........new 410 rear has been installed and I will test it tomorrow. Thanks BCOWANWHEELS

I now have a complete rear with axles, housing and 514 3rd member for sale if some of you mud boys might be interested.

[capev86]

stupid that they didn't have a couple milder gear ratios considering they used the ho52 and ho72 for 35 years. but gas was cheap back then and the corp/eaton was designed when pickups spent most of their time on the farm, not prowling the new highways being built.

a 4.10 is a good gear for a truck with a serious engine and with an overdrive will be nearly as good as a 3.73 on the highway due to the 3/4 and 1 ton trucks having taller tires than 1/2 tons. they weigh more and haul heavier loads also, so the little extra is useful!

[capev86]

looking forward to hearing how you like it. i have a 4.57 that i want to swap for the 4.10 so i can drive above 50mph without screaming the engine (i shift it into 3rd/top gear at about 20 mph on level ground).

[72freak]

Originally Posted by capev86

looking forward to hearing how you like it. i have a 4.57 that i want to swap for the 4.10 so i can drive above 50mph without screaming the engine (i shift it into 3rd/top gear at about 20 mph on level ground).

I will be interested in seeing your results...I would not think there would be that much difference from a 4:56 to a 4:10.