gearing for 39.5s

hummer_maxxer · Feb 19, 2008

hey i was just wondering what kinde of gearing i would use with a stock 2.9l and locked front and rear 44 and 9". or is it just too much for the motor and tranny??

mkpecor · Feb 19, 2008

um,put a 302 you will be better off, that is alot of waight, my budy had 38"s on his 87 ranger and he went back to 35s

Sunk · Feb 19, 2008

You would well into the 5.xx range, or, more likely, the 6.xx range. I don't know what ratios are made for those axles, but I believe I've seen 6.20 for the 9".

As previously stated, I would go with a V8.

LittleBigFoot · Feb 19, 2008

Randy's Ring and Pinion has a 6.50:1 ring and pinion set for the 9". Deepest I've seen for the D44 is 5.89
Holy crap.

I'd suggest 5.13s, 37s, and a doubler for the trails

Evan · Feb 20, 2008

hummer_maxxer said:
hey i was just wondering what kinde of gearing i would use with a stock 2.9l and locked front and rear 44 and 9". or is it just too much for the motor and tranny??

You would want the lowest gearing possible. If you have a 2.9L with an A4LD or FM146 you'd probably blow the tranny pretty quick. If you have a 2.9L with an M5OD, you'd be ok but a little underpowered.

The easiest and maybe cheapest option would be to do a 4.0 swap and run an M5OD, and the lowest gears possible in the axles. That would give you a reliable setup with good power.

The best option would be to run a 302 mated to an NP435 or C4, and low axle gears. This would cost some $$$ potentially and involve some fab work.

Be warned: 39.5s will tax a Dana 44 pretty heavily. You'd probably be better off in the long run with a 60.

hummer_maxxer · Feb 20, 2008

ok, thanks, i plan on doing a 302 swamp but thats next year. and also il be running chromoly axle shafts so the 44 would be strong enough. I think il just get a set of used 35s until i put in the 302.

Tweeder · Feb 27, 2008

i'd stay the hell away from a D44 if you wanna run 39.5s, do a 35-spline 9", and 5.38 gears for a gas engine. you'll definately want a doubler if you crawl.

hitech_hick · Feb 28, 2008

Tweeder said:
i'd stay the hell away from a D44 if you wanna run 39.5s, do a 35-spline 9", and 5.38 gears for a gas engine. you'll definately want a doubler if you crawl.

x2, as mentioned 40" tires and a Dana 44 = BOOM

Even with chromoly shaft, all you are doing is moving around the weakest link. Run 35's for a while, and once you have out grown them, consider a set of Dana 60's...

hick

Tweeder · Feb 28, 2008

hitech_hick said:
consider a set of Dana 60's...

FWIW, a 9" owns a rear D60.....just as strong, better clearance, lighter weight. if he upgrades to a 35-spline 9" like i said (big bearing nodular 3rd, Detroit/ARB/spool, 35-spline shafts), he can run up to 44s without any issues if he drives smart.

for the front, either a D60 or, for clearance and weight, a 60-9 hybrid (9" centersection with D60 knuckles and outers.)

RWARanger · Feb 28, 2008

maybe if your rich you'd run those axles. almost all the axles you mentioned are well out of the normal persons price range. and why would you spend $3000+ on a 35 spline 9" to have to "drive smart" with it. 40"+ tires ff 14 bolt or d70. in his situation 5.38 and a bigger motor

Tweeder · Feb 29, 2008

i'm just saying that a "set" of D60s aint exactly ideal when you've already got a 9" on hand. stock 60 rear would be 30 spline vs. a 31-spline 9". 9" has a better centersection as far as gear strength, to boot. only thing you can get with a rear 60 that you'd hafta build for a 9" is a full-float setup. but you still gotta build either axle to run 40s.....chromos, gears, lockers, etc...depending on how you go, one's just as spendy as the other.

for the front, if you wanna run 40s you one only one option.......something with 60 in it. 44 just won't cut it -- even with a RATHER anemic 2.9L

as to the "driving smart" bit.....44s are getting up into the range where you NEED Rockwells to avoid axle detonation everytime you start the engine. you CAN run em with some heavily built Dana, Ford or Chebby axles, but you gotta drive smart.

hitech_hick · Mar 1, 2008

Tweeder said:
FWIW, a 9" owns a rear D60.....just as strong, better clearance, lighter weight. if he upgrades to a 35-spline 9" like i said (big bearing nodular 3rd, Detroit/ARB/spool, 35-spline shafts), he can run up to 44s without any issues if he drives smart.

Not going to argue that point, and honestly, the Ford 9 inch (and to lesser extent the Ford 8.8) venture far further into the 1-ton strength range than most other 1/2 ton axles. The reason that I see more guys ditch 9" (or 8.9) in favor of a Dana 60 is because they are upgrading the front axle, and they want to keep the width and lug pattern the same.

for the front, either a D60 or, for clearance and weight, a 60-9 hybrid (9" centersection with D60 knuckles and outers.)

RWARanger said:
maybe if your rich you'd run those axles. almost all the axles you mentioned are well out of the normal persons price range. and why would you spend $3000+ on a 35 spline 9" to have to "drive smart" with it. 40"+ tires ff 14 bolt or d70. in his situation 5.38 and a bigger motor

Honestly I would rather run a built 9" or a built 60 than a stock 14 bolt. You have to shave the hell out of them to get any ground clearance (which is the purpose of running bigger tires) and then you are still left with a boat-anchor of an axle

Tweeder said:
i'm just saying that a "set" of D60s aint exactly ideal when you've already got a 9" on hand. stock 60 rear would be 30 spline vs. a 31-spline 9". 9" has a better centersection as far as gear strength, to boot. only thing you can get with a rear 60 that you'd hafta build for a 9" is a full-float setup. but you still gotta build either axle to run 40s.....chromos, gears, lockers, etc...depending on how you go, one's just as spendy as the other.

for the front, if you wanna run 40s you one only one option.......something with 60 in it. 44 just won't cut it -- even with a RATHER anemic 2.9L

as to the "driving smart" bit.....44s are getting up into the range where you NEED Rockwells to avoid axle detonation everytime you start the engine. you CAN run em with some heavily built Dana, Ford or Chebby axles, but you gotta drive smart.

Definitely agree with the 60 bit, no stock axle is made for this kind of abuse, even a kingpin HP D60 will need to be built up a bit even to wheel 35's. As for 44's requiring a set of rocks, depends on the terrain, driving style, and motor. I would love to see you bust a rockwell with a 2.9, not saying that it couldn't be done (think Klune + 10 to 1 Atlas), but it sure would be a sight to see.

hick

VaGent · Mar 1, 2008

I'm looking for some gears to replace my 3.73s. Where can I go to find something like 3.55s or 3.45s. I want them for my wife's BII 2X4 for highway use only. New to a lot of this stuff. Any help would be appreciated. Thanks

Jim Oaks · Mar 1, 2008

I have a 302, 4.56's and 33's. When I rebuild my Dana 60's I'll be gearing for 40's and running 5.38's.

I used our gear calculator in the tech_library to determine that going from 33's to 40's would require me to upgrade to 5.38's from 4.56's to maintain the same performance.

gearing for 39.5s

hummer_maxxer

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mkpecor

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Sunk

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LittleBigFoot

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Evan

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hummer_maxxer

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Tweeder

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hitech_hick

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Tweeder

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RWARanger

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Tweeder

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