Swapping 3.54 gears have a few questions/opinons needed

[Archbronco]

Hello-
I just purchased my project Bronco and have inspected the hardware. The Bronco has a stock 3.54 Dana 44 w/ Disk brake conversion in the front and a 9" in the back (75 Bronco). I have a NV3550 Transmission that came w/ the truck that I would like to put in it. I have read a few threads on 3.54 gears w/ 31-32 tires, being a very sluggish ride. I am thinking about swapping the gears out, but need a good handle on how to do this. I will having a axle shop do the seals etc. I would rather not use "thick" gears, unless you guys have had good experience with them.

I am leaning to swapping the carrier out for the 4.11+ gears on the Dana 44 Front, but would I have to swap out the rear?

What are some cost effective ways to do this?

Will this be my best option for utilizing the NV3550 OD w/ 31-32 Tires and a rebuilt 302?

 

[73stallion]

for 32's i'd go 4.11's. friend of mine is real happy with that setup. i have 4.11's with 33's and NV3550, i can do 75 all day long.

 

[Archbronco]

I am thinking about going with a ARB air locker front and rear and changing the gears to 4.11/4.56. I am wondering if the ARB w/ New Gears will fit inside the Dana 44/9" that's currently running 3.54? Anyone have experience in this?

 

[wdbowers]

what is you intended use of your Bronco, that will help determine which ratio to go toward. the gears you mentioned will fit in the housings ans if you are going to buy ARBs for both front and back, the one for the 9" will fit all ratios you are thinking about but the 44 breaks at 3.94 I think but as you mentioned you would have to use thick gears for 4.11s. if you intend to go to lower gears in the future go with the higher number carier(ARB) and you will have to match the front and rear ratios to within a few points.

 

[JIMS74]

With the 5 speed trans, I think you would be happy with 3.54 gears and 32" tires. IMHO
Jim

 

[Archbronco]

@wdbowers- I want a street friendly truck w/ some good trail ability. I also would like to be able to use the OD from the NV3550. If I understand you correctly, and please correct me if I am wrong, the Dana 44 Front Axle I have (Set up at 3.54) will accept a <3.92 ARB Locker w/ Thick Gears of 4.11+, but will not accept a >3.92 ARB Locker w/ Normal Gears? Also- The 9" rear will be fine running >3.92 ARB w/ Normal Gears?


@JIMS74- I have been reading and reading about NV3550 and RPM w/ OD being very low w/ 3.54 and possibly 4.10. I am trying to make a solid plan based on your opinions on what to build. I believe the 3.54 would be fine for backstreets and cruising to the mall, but I would like to be able to get on the highway and use that NV3550. I could be all wrong though and appreciate your opinion.

 

[thegreatjustino]

With the 5 speed trans, I think you would be happy with 3.54 gears and 32" tires. IMHO
Jim

Overdrive would most likely not be in the correct power band making it effectively useless

 

[Broncobowsher]

The 9" does not have a split. Any gear ratio will interchange. same diff/locker/posi/whatever for anything from a 2.41 gear to a 7.17 gear. There are engouh different ratios available for the 9" you can get one that will work with any front ratio you could find for the D44.

3.50 gears, 32's, and overdrive? not a good plan for a Bronco. The 4.10 window would be a lot better. Fine tuning that ratio a little (3.92, 4.30, possibly 4.56 maybe?) depending on your driving habits, local conditions, how the 302 was rebuilt (powerband), etc. Just need to play with the gear/speed/MPH calculators a little bit. Have you driven that rebuilt 302 yet to see how it feels at different RPMs?

 

[Archbronco]

@broncobowsher- Thanks for the clarification on the 9". As for the motor, I will be dropping it in after I allot more work, but it is a fresh rebuild 302 bored .30 over w/ edelbrock cam and lifters and edelbrock aluminum intake. I believe the forum has some good calculators for tire size/engine/gear ratio that I have been looking at, but I need to know if the ARB locker will work with normal gears or will I have to use "thick" gears. In essence will the ARB locker work as my carrier for >3.92 normal gears or will I have to get "thick" gears. I may just call Randy's in the morning and see if they can shed some light on this too.

 

[broncnaz]

With a 3.92 up carrier you can use standard gears. Thick gears are for 3.73 down carriers. With your stated engine combo I would go with 4.30 gearing and if you ever decided to step up to 33in tires you woulld still be fine. You would have nice lowend and hiway driving with little to no power loss on hills while in OD

 

[turbotim2]

There is no problem using thick gears on the 3.73 and down carrier.

 

[wdbowers]

either carier will work in your 44 but if you bought the 3.92 down one and decided to go with 4.56 later you would have buy another ARB carier.

 

[Broncobowsher]

I thought there were limited options in gearing with thick gears. Not all the ratios are available?

 

[turbotim2]

I thought there were limited options in gearing with thick gears. Not all the ratios are available?

I know some of the popular ones are available - 4.11, 4.30, 4.56. Not sure on others.