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To gear, or to gear.... that is the question..

Stick with the half ton stuff unless you get a super deal on 3/4 ton stuff.

I actually was looking here in Lexington, KY on Craigslist today and sure enough there were several sets of half ton axles. Most expensive was $300.




chuli, the 700R4 started in '82. It and the 6.2L were new that year.
 
I say figure out what you have first and then go from there, but if it turns out you have 3.08s I say keep them and find a turbo setup for cheap to make more power and keep the tires stockish for awsome mpgs. The stock axles go for free to cheap around here, I couldn't sale or give mine away so off to scrap they went.
 
AJMBLAZER said:
chuli, the 700R4 started in '82. It and the 6.2L were new that year.
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ok i thought somewhere in there 84ish,but was still thinkin cucv blazer because of the 6.2 in my head i guess.i still vote 3.73 with 33 inch tires being the max size to keep those gears.
 
Okay, as soon as I can get my dime on, Ill fetch up some 3.73 1/2 tons, and Ill be running 31's till they bald out then maybe some 33's.

I dont think a Banks/65turboswap is in my mechanical capability. The axle swaps will be no problem, Ive done one like that already. :woot:

Thanks a lot for the input!
 
Honestly I think you'll be surprised with the "pep" with the 3.73's. I've only owned low geared 6.2L trucks (including a M1008 CUCV on 38's) and I have never found them doggy. Not fast, but not slow off the line.
 
if i was building a house in Florida i wouldn't engineer the roof to support 300" of snow........my truck will be primarily a DD/work truck that'll see some limited wheeling(like Rausch Creek), camping trips and such. i'm going to keep my 3.73 geared 30 splined 10 bolts and go with some nice 33's. mebe an E-locker up front for WHEN it's needed. a sf 14 bolt wouldn't hurt though, if it could be had for a nice price. if i move to where there's real wheeling on a regular i'll do a bulletproof truck. this economy sucks to be throwin good money at problems that don't happen much........just my $.02, for what it's worth.
 
My '90 6.2/700r4 K5 had 3.73 gears stock and I ran both 32's and 33's and it seemed fine. I later upgraded to 4.10's with the 33's...it was probably more optimal but there really wasn't enough difference between 3.73 and 4.10 to notice.

If you have 3.08's I definitely agree with buying a set of 3.73 geared axles really cheap and bolting them on. Another option would be to find a pair of 4.10 geared 3/4 ton (10-bolt front, 14-bolt rear...SF or FF) for just about as cheap. This would give you a pretty much bulletproof rear axle you would never have to worry about for minimal extra work and cost (biggest cost difference would be buying 8-lug rims).
 
6.2Blazer said:
3/4 ton (10-bolt front, 14-bolt rear...SF or FF)
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Ill look into that, but what vehicle? :dunno:

If I go to car-part.com, there is options for

Chevy Truck 10 Series
Chevy Truck 20 Series
Chevy Truck 30 Series

IIRC, the Blazer never came with 3/4?

Thanks!

Andrew
 
Chevy Truck 10 Series = 1/2 ton
Chevy Truck 20 Series = 3/4 ton
Chevy Truck 30 Series = 1 ton

Keep an eye on your local cragslist too. Sometimes you can find clapped out K20s real cheap. This would get you a 10b 8 lug front and at least a 14b sf 8 lug rear with either 3.73s or 4.10s. Plus many other parts you can keep or sell. Swap the axles and sell or scrap what's left.
 
its too bad you are are not closer to oregon. $175 would get you a d44/ff14 combo with 3.73s. with all the nessecary parts to install
 
Okay, thanks... The truck series is like I thought, but being a dumbass, I had to ask to make sure.

Yeah, Id love to have a set of axles that are hub to hub for streamlined transfer! Im not a big axle guru, so swapping knuckles and bearings is NOT in my repertoire.

And if I score a pickup, I can whack the frame in front of the bed and fab up a quick redneck trailer.

Of course, if it wasnt for bad luck, Id have no luck at all so Im kinda guessing none of this will ever pan out for me. :doah:



Off topic, but curious: When I was serving, I drove the **** out of M998's. IIRC, they were 6.2NA in the early times and then went to (?) 6.5NA. The HMMWV were never turboed (that was a big mistake too). I think (?) they had 400 for a trans, it was only a 3 spd. Does anyone know what the gearing was? I know the damn thing would be sCrEaMiNg going down the highway at 65!


Again, off topic... But wasnt the 1009's 4.11, or 4.56?? I really dont think it was 373.

I hope to have free time to jack a tire and spin a rev to check gearing, Ill also do a utube vid so someone who doesnt know, can figure out there ratio too. (My RPO sticker is missing).


Cheers and THANKS TO ALL THAT HELPED!

Andrew
 
DieselWarrior said:
Okay, thanks... The truck series is like I thought, but being a dumbass, I had to ask to make sure.

Yeah, Id love to have a set of axles that are hub to hub for streamlined transfer! Im not a big axle guru, so swapping knuckles and bearings is NOT in my repertoire.

And if I score a pickup, I can whack the frame in front of the bed and fab up a quick redneck trailer.

Of course, if it wasnt for bad luck, Id have no luck at all so Im kinda guessing none of this will ever pan out for me. :doah:



Off topic, but curious: When I was serving, I drove the **** out of M998's. IIRC, they were 6.2NA in the early times and then went to (?) 6.5NA. The HMMWV were never turboed (that was a big mistake too). I think (?) they had 400 for a trans, it was only a 3 spd. Does anyone know what the gearing was? I know the damn thing would be sCrEaMiNg going down the highway at 65!


Again, off topic... But wasnt the 1009's 4.11, or 4.56?? I really dont think it was 373.

I hope to have free time to jack a tire and spin a rev to check gearing, Ill also do a utube vid so someone who doesnt know, can figure out there ratio too. (My RPO sticker is missing).


Cheers and THANKS TO ALL THAT HELPED!

Andrew
Click to expand...

the m1009 were 3/4 ton blazers IIRC and i believe most commonly stock gearing in the difs was 3.08. The m1008 were the one tons and they had 4.56 gearing again IIRC :D
 
The HMMWV's did get the 6.5L turbo diesel starting in the late 90's. Still slow as they kept getting heavier. I have about 900 of them now and I swear they feel slower than the old unarmored, 10 year old M998's I drove in the Marines.

They also originally had the TH400's without a parking gear. Then came the 4L80E's.

I forget the exact number but HMMWV's had a portal setup with 2.xx something gears in the diffs (AMC 20 centers) and I want to say 3.xx at the hubs? So yes, they were slow. The civilian H1 Hummers are higher geared so they can go faster.

He's correct, M1009 Blazers had 3.08 gears and the pickups had 4.56's regardless of the models.

The weight ratings are deceptive. GM used the common designations (and still does) of 1/2 ton, 3/4 ton, and 1 ton while the military actually measured the vehicles by their true rated capacity. Don't buy a M1009 and expect it to be any tougher than a similar K5.

As far as the axles go, for what you want to do I say find half tons unless you get a screaming deal on 3/4 ton axles. You're as likely to find either but hey, the half tons will bolt in and not require anything except for new U-bolts and possibly a conversion U-joint if you get a 12 bolt rear.
Wouldn't pass up a decent set of 3/4 ton axles but again, things are getting slightly more complex and a 14FF is serious, hardcore overkill for 33's.
 
Welcome.

I'm a font of random military knowledge.
 
hummwv definitely were not made for speed.the 6.2 would crawl over just about anything though.top speed on mil model hummvee was rated at 55 mph.any higher and the engine was screamin at you.no tach so i fdont know what rpm they were turning at but loud as hell at that speed and the radial tires didnt help.the gearing was multiplyed by the portals and i believe as ajm said around 6 to 1 final ratio.i worked on the old ones with the th400 and 6.2.they were nice ride but in the field we were "supposed" to keep them under 35.yeah right.haha.as for axles for your truck,i wouldnt worry about going 3/4 ton if you are stickin to 33s.your toothpicks i mean 10 bolts should hold up fine.lol.
 
I havent had time to jack a tire for a rev and check my ratio yet, been busy putting in job applications and doing some nick nack work on the WarWagon (Got a nifty air horn hooked up today, woot woot).

image_768.jpg

(Harbor Freight, $15)



I did have a quick Q: If I do have 308, would switching to 373 improve my MPG noticably??




.
 
Easiest way to ensure best mpg for a 6.2 rig is gear it so it's turning right around 1800-1900 rpm at 65 mph.

3.73's and 31" tires (true diameter) puts it right at 1839 rpm. 1728 rpm with 33's. The thing is most 33's measure out at a true 31.5"-32", and 31's are similarly smaller than advertised. 3.73's with either the 31's you have or the 33's you may have in the future will net you the best fuel mileage. For a bit more power you could go with 4.10's, at the expense of ~ 1 mpg highway.

My old Jimmy had 4.56's, 39.5's and a SM 465 (no OD) and it was spinning that poor 6.2 at 2600 rpm on the highway. Very hard to get used to listening to a diesel spin like that..but it still got an average 16+ mpg doing it and they were built to deal with rpm's on the higher side of average for extended periods.

Rene
 
I wanted to add that the most reliable way to find your gearing is to pull the diff cover, and check the numbers stamped on the edge of the ring gear. A lot have pinion tooth count and ring gear tooth count stamped as well as a date of manufacture.

some have the ratio itself stamped. My 12 bolt has the ratio stamped. Every 14 bolt I've looked had pinion/ring tooth counts (41-10 for example)

Rene
 
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