2.73 rear end ratio no kidding

[BaconFarms]

All,

Haven't been on here in a couple years, so I come on as a new member as I forgot what email or user name, etc. No biggie.

Anyway, I purchased a M1009 from Ft McCoy about 3 years ago and have used it for just about everything to include snow plowing. This summer I was towing a treeplanter and blew the rear end out of it. Hard, the ring gear was sticking out the cover.

So I ordered all the parts and had a extra housing ready just in case the post mortum showed a busted housing.

Today, I got it on the lift and pulled it apart and found a 2.73 ring and pinion. I have a new 3.08 on the workbench as that is what everything said it required. So, now I was concerned and pulled the front cover to find a 3.08 ring and pinion.

It came from the military with 47,000 miles on it. It always bucked in 4WD and would skate side to side on ice. You could not go to town in 4WD. I just thought it was heavy duty military and that was what was supposed to happen, etc. It plows snow like a SOB. You can't beat it.

Anyway, anyone hear of a 2.73 rear gear in a CUCV, or more likely, some military mechanic replaced it with the wrong ratio.

Also, didn't know of too many trucks that came with 2.73.

Thanks,

BaconFarms

 

[doghead]

so I come on as a new member as I forgot what email or user name, etc. No biggie.

Multiple accounts is against the rules. You should have contacted us and found your old account.

 

[Keith_J]

No kidding, a 2.73. Guess that would fit the 3.08 carrier. Snow plowing with that mismatch would certainly be interesting. Guess the rears were being dragged along.

 

[doghead]

Did you original account have "bacon" in the name?

any of these ring a bell?

bacon225 Bacon4x bacon713 bacongreg5 BaconJack

 

[trukhead]

Cool, Put the new gears in and see what happens. Hopefully smooth as that flag bikini top in some previous post, Oh My!

 

[jeeplvr247]

I have never heard of the military doing that. It was probably a civi mod to get the revs down a bit on the highway. I test drove a M1008 last year that was in "military stock" condition or so the owner said. I about went off the road when I took off in 4wd. I think it had a 3.08 in the rear and the original 4.56 up front. Then I just argued with the owner about whether or not that kind of bucking is normal in a 4x4. Some people...

 

[Goose2448]

I think the 2.73s come in Corvettes. Oh man we have a ricer on our hands.

 

[BaconFarms]

Did you original account have "bacon" in the name?

any of these ring a bell?

bacon225 Bacon4x bacon713 bacongreg5 BaconJack

Sorry about that, but tried for 30 minutes and couldn't get any thing to work. I think my old login would have been cb1. Not sure on that.

Thanks,

BaconFarms

 

[BaconFarms]

I have never heard of the military doing that. It was probably a civi mod to get the revs down a bit on the highway. I test drove a M1008 last year that was in "military stock" condition or so the owner said. I about went off the road when I took off in 4wd. I think it had a 3.08 in the rear and the original 4.56 up front. Then I just argued with the owner about whether or not that kind of bucking is normal in a 4x4. Some people...

Bought from the military on Ft McCoy. Don't know how a civilian would have worked on it.

BaconFarms

 

[doghead]

Any of these, it?

cb1000h CB121 CB140

 

[73m819]

Bet it WAS the "SHOP PARTS RUNNER TRUCK", they tricked it because they wanted MORE speed, but bet never used in 4x4

 

[BaconFarms]

No, I don't think so.

 

[BaconFarms]

doghead,

I come to realize, I may have only looked here in the past and never posted. I can't remmember. I am getting old. I do believe I did have a login and password. But I could be wrong.

If you can look at my profile and see if anything matches up and delete my older user name. I went back and check my emails from that long ago and see nothing.

Sorry about not letting you help out with the registration.

BaconFarms

 

[BaconFarms]

Bet it WAS the "SHOP PARTS RUNNER TRUCK", they tricked it because they wanted MORE speed, but bet never used in 4x4

She's probably going to be a fuel hog now.. Ha, ha.

She actually did quite well on fuel (mpg). Alot better than my 1ton gas pickup.

BaconFarms

 

[Keith_J]

I doubt 2.73 gears would make any difference in fuel mileage. It isn't much of a jump down from 3.08 in engine speed. Besides, the engine is already operating at below its peak torque with 3.08, dropping it further will do nothing.

Remember, peak torque corresponds to peak cylinder pressure since pressure x area is force. Peak torque is where the engine is most efficient, thermodynamically In diesels with mechanical injection systems, design of volumetric efficiency peak is around mid engine speed band.

 

[panzerwillie]

I ran 2.73 and even 2.56 on my M1009 for some time , is nice on the HWY speeds if you run 70-75MPH of course mine has a turbo so helps all around, those ratios where more of camaros , nova, chevelles ect all 8.5 GM ring gears are the same even the H3 will work, the ratios work from 2.73 up to 3.90 with the same carrier , i cut down a stock 8.5 open end to run the 2.56 because of the larger pinion count, if you had 3.08 on the front and 2.73 on the rear even on 4x4 would not be a big deal on snow , mud or wet conditions only on dry ground, you can mark the front tire lift that side tire and lock the hobb and count 1 full revolution on the tire and have some one watch the yoke, if is open end and spins just over 1.5 turns is 3.08 less than 1.5 turns is 2.73 if is not a open carrier then it would give you the full amount of rotation for the gear just under 2.75 for 2.73 or just over 3 revolutions for 3.08 hope this helps

 

[trukhead]

I ran 2.73 and even 2.56 on my M1009 for some time , is nice on the HWY speeds if you run 70-75MPH of course mine has a turbo so helps all around, those ratios where more of camaros , nova, chevelles ect all 8.5 GM ring gears are the same even the H3 will work, the ratios work from 2.73 up to 3.90 with the same carrier , i cut down a stock 8.5 open end to run the 2.56 because of the larger pinion count, if you had 3.08 on the front and 2.73 on the rear even on 4x4 would not be a big deal on snow , mud or wet conditions only on dry ground, you can mark the front tire lift that side tire and lock the hobb and count 1 full revolution on the tire and have some one watch the yoke, if is open end and spins just over 1.5 turns is 3.08 less than 1.5 turns is 2.73 if is not a open carrier then it would give you the full amount of rotation for the gear just under 2.75 for 2.73 or just over 3 revolutions for 3.08 hope this helps

Are you familiar with the M1008 coproraete 14 and dana 60 drive axles?
Secifically are there conversion gearset to go from series carriers in the 14 and 60 to use 3 style ratios? I've used the internet but never found a clear answer?

Found this thread but no info on conversion sets: Re-Gearing Axles? This Marine Seeks Wisdom.

 

[Whitfield]

I owned a 1980 K-10 Pickup with stock 2.73:1 diff gears.

It had a 350 / TH-350 / 205 package.

I bought it with a wheezed 350, 4" lift and 35" tires. Talk about a pig...

 

[Keith_J]

Did the mod finally tire of picking fights in retirement homes? Welcome, BaconFarms. My CUCV is a former CheeseHead MV. Too bad we didn't have time to enjoy Wisconsin more on the recovery.

I can only surmise the federal supply system was quite lean in the late 1990s when this CUCV needed a ring and pinion swap which might have been done by on-post Directorate of Logistics Direct Support facility (civilians) who could source parts locally quicker than through the diminished inventory in federal supply chain.

I know low demand items were surplused When alternate sources are used, mistakes happen. Not to dog on DoL employees, it is possible they didn't know the source of the parts, thinking they were 'approved and correct parts'. When you are a WG04, do you question such things?

 

[BaconFarms]

It had a Gov-Loc with clutch packs. Never saw them together before. Anyway the new one is going to be open. Don't need a locker for what I do. And it should work better in tight spaces. Like plowing. I only do six driveways. Not because I want to, but because I have too.

So far, I am up to locating a inch-pound torque wrench to set pinion pre-load. Never had one, probably should get one. Tomorrow, hit up the neighbors, or go to town and buy one. Probably have to order. The guy at the parts counter is going to look at me cross-eyed when I ask him to get me a inch-pound torque wrench.

BaconFarms