Hey guys newbie here :eek: :eek:

I just bout a 1971 Bronco and well gonna make some changes. It has the D44 front and the Ford 9" but here is the deal.

I am installing a 3.9L 4cyl. Cummins turbo diesel in the Bronco and I don't think the 9" of D44 will handle the HP and TQ the motor will produce.

I am expecting at least 700ft. lbs of TQ out of the motor.

What would yall suggest as some good axle options? I thought mebbe a D60 front and rear........cause I just don't think the D44 and 9" will handle it

BTW here is the Bronco and Truck http://memimage.cardomain.net/member_images/2/web/494000-494999/494375_45_full.jpg

why exactly are you wanting to put a diesel in it?

why exactly are you wanting to put a diesel in it?
Cheaper Fuel, more reliable, more TQ and HP, easy to fix, cheap to mod, and then you have the coolness factor

Here is a 3.9L Cummins Turbo Diesel already in a Bronco
http://www.diesel-central.com/photogallery/pictures/Ad_83_1.jpg

with some work, the 9" will survive fine. Remember that rear has been used in high HP/Tq applications for drag racing for eons.

for the front? Hell if I know

to put the 9" into perspective, my brother has an 8.8" in his Capri and its running mid/low 9s at over 140 with nothing but a reinforced diff cover, 35 splines and a spool.

put some 31 spline or better axles in the 9" and you should be fine.. May want to step up to a later model housing that is a bit stronger though.. (or have one built so you can retain the proper width if you're worried about it)

the 44 though.. can't say.. I'm sure it'll last as long as you don't actually use 4wd.

Your probably going to want to go to a minimum of 31 splines in the rear and some quality alloy shafts up front...Now if you plan on locking the front/rear I'd say 35 splines and CTMs up front...Now if you plan on going w/ tires above 35's, I'd say start looking for a 60 front and 14 bolt in the rear.

What's the trans gonna be?

Your probably going to want to go to a minimum of 31 splines in the rear and some quality alloy shafts up front...Now if you plan on locking the front/rear I'd say 35 splines and CTMs up front...Now if you plan on going w/ tires above 35's, I'd say start looking for a 60 front and 14 bolt in the rear.

What's the trans gonna be?Yeap plan on later runnin an ARB air locker front and rear.

Tranny, T-case setup is gonna be a NV4500/241

What size tires do you plan on running? Im assuming if you're shooting for 700tq that the little motor will be hella-bombed. I would not even consider the front 44..... even if you went warns/CTM's. With that much torque right off of idle and the crawl ratio you're gonna have it seems like a timebomb waiting to happen. If you were keeping the little Cummins stock id say the 44 with warn/CTM might make it, but IMHO its D60 time with 35spline outers.

What size tires do you plan on running? Im assuming if you're shooting for 700tq that the little motor will be hella-bombed. I would not even consider the front 44..... even if you went warns/CTM's. With that much torque right off of idle and the crawl ratio you're gonna have it seems like a timebomb waiting to happen. If you were keeping the little Cummins stock id say the 44 with warn/CTM might make it, but IMHO its D60 time with 35spline outers.
36" M/T's of some kind.

The Cummins comes with 110hp.....then it gets higher HP jectors, twin turbos, 5" exhaust, and a turned up pump

36" M/T's of some kind.

The Cummins comes with 110hp.....then it gets higher HP jectors, twin turbos, 5" exhaust, and a turned up pump
I was wondering what you were going to do to get 700 ft lbs torque out of yours. At 110 hp stock, what is the CPL number of your engine? Is it a rotory or inline pump? Do you know anyone that has bombed a 4B in your projected manor to get those kinds of numbers?
If you do get those kinds of numbers out of it, no, I doubt your axles will hold up to it. Don't know how long the 4500 will live either, as it's rated torque capacity is much less than 700 lbs, as I recall..........could be wrong on that though as I'm going from memory.
Where ya located?....and have I talked to you before? Your pic of the installed Cummins is my rig.

what o ou get a 3.9l cummins out of

what o ou get a 3.9l cummins out of

Mostly they're found in decomissioned Frito Lay vans, but can also be found in Dolly Madison donut vans, many bread company vans, etc. There's a salvage yard in Georgia that I got mine from, about 50-75 miles southeast of Atlanta.....Avant Salvage, owned and operated by a fella named Benny. Cant think of his last name right off.

Where ya located?....and have I talked to you before? Your pic of the installed Cummins is my rig. DUDE I been trying to get ahold of you forever......dang your hard to get ahold of.

I got that pic from Diesel-Central been trying to e-mail you for about 3 weeks...keeps shooting the e-mails back. (go check my thread over there looking for you)

I think we have talked before about axles about a year ago.

As of right now I don't have a 3.9....I just got the Bronco last weekend.

But to the 3.9 will bomb out just like the 5.9 will....you can buy all the same performance stuff for the 3.9 as you can the 5.9.

If you could please send me a pm I have SEVERAL questions I need to ask you.....thanks for your time

PM'd you.

PM'd you.This is so damned awesome......dude I been trying to get ahold of you forever.......I'll try and give you a shout tomorrow

d60 front for sure with anything over 400# torque if you ever plan to get rowdy with it in low range.

After seeing what my buddy can do with his Caterpillar diesel in his buggy, I am damn convinced thats the way to go, no electronics to soak like I did!

If you're looking for a decent transmission you could try Boyce Equipment. They got the Spicer Model 3053A which is a beefy tranny. Quote from Boyce:

Military Transmissions

We offer the transmission that was used in the truck that holds the land speed record for one ton range and up-the Spicer Model 3053A. Fully syncro-ed and will hold up to large horsepower gas and diesel engines. Replacement parts always in stock. Make: Spicer

Model: 3035A

Gear Ratios:

Reverse 5.90:1

First 6.00:1

Second 3.31:1

Third 1.89:1

Fourth 1.00:1

Fifth 0.85:1


Think this might work.

what type of vehicle had this 3.9 diesel motor in it seems like a good setup though should be cool.

I would go with a HD-44 front and D-60 rear

'nother vote for 1 tons.