CUCV axle question

[Monster Man]

hello all, I thought I was clear on the CUCV- that it had a 1 ton front and rear axle, the rear witha detroit.


Now, I have noticed conflicting information in three different spots- the first being a standard catalog of 4 wheel drives stating the obvious, that the K30 had a full floating 1 ton rear and a semi floating 1 ton front. The K20 had a semi floating rear, equivalent almost to the 1 ton but it was semi floating, and the front axle was weaker.



In the standard catalog of military vehicles, it says the CUCV was built off a 3/4 ton chassis with a 1 ton frontend. But how could that be if it has a full floating 14 bolt rear?



In Military Vehicle Magazines, it says the CUCV was just a 3/4 ton with "limited" slips front and rear, which is wrong



I just want to confirm what running gear this truck has? I'm looking to upgrade my Chevy truck in the future to a CUCV, if it has the best standard truck running gear available (well, I'll keep my NP205 unless I can find the CUCV with one), but am not sure I want to do that if it's only 3/4 ton. So is it a real 1 ton (or 1 1/4, whatever ) or just clever ratings by Uncle Sam?

 

[Prerunner1982]

the only 3/4 ton is the M1009 blazer... which you probably dont want parts off of.
to get the 205. you need to look for a m1028a1, m1028a2 (dually), or the m1031.
the 1tons are definately 1 ton running gear.. the blazers were intended more for personell use.. trucks were meant to be abused.. they are heavier duty.

 

[Monster Man]

very good, thanks. Yeah, I figured they would be based on one tons, I don't know where the info came from they were based on 3/4 tons well the m1009's, yeah

 

[Recovry4x4]

Here's the scoop on the CUCV axle. Blazers have 10 bolts front and rear. Pickups, and cab/chassis have the Dana 60F and 14 bolt rear with a detroit. All models except those requiring PTO stuff have the 208 transfer case. Models requiring PTO stuff including the M1031 had the 205 case. The 60f 14bolt stuff has 4.56 gears and the blazers have 3.08 gears. Does that clear it up?

 

[Monster Man]

Here's the scoop on the CUCV axle. Blazers have 10 bolts front and rear. Pickups, and cab/chassis have the Dana 60F and 14 bolt rear with a detroit. All models except those requiring PTO stuff have the 208 transfer case. Models requiring PTO stuff including the M1031 had the 205 case. The 60f 14bolt stuff has 4.56 gears and the blazers have 3.08 gears. Does that clear it up?

yup- except, to confirm the CUCV trucks had a full float 10" 14 bolt, instead of the 3/4 ton 9.5" semi float 14 bolt?


thanks!

 

[sodbuster]

Three quarter ton trucks came with both 9.5 inch semi-floating fourteen bolts with a c-clip stly axle, and a full floating fourteen bolt differential. One was a light duty three quarter ton and one was a heavy duty three quarter ton. All one ton single wheel trucks came with the full floating fourteen bolt in them. The cucv does come with the full floating rear end.

 

[Monster Man]

Three quarter ton trucks came with both 9.5 inch semi-floating fourteen bolts with a c-clip stly axle, and a full floating fourteen bolt differential. One was a light duty three quarter ton and one was a heavy duty three quarter ton. All one ton single wheel trucks came with the full floating fourteen bolt in them. The cucv does come with the full floating rear end.

very good, thanks. So then when they said the CUCV was based on the 3/4 ton, it was the "heavy duty three quarter ton with 1 ton front axle", or, in other words 1 ton. Cool thanks

 

[Bob H]

[No message]

 

[Recovry4x4]

[No message]

 

[spicergear]

M1028 has a posi in the front too. I'm unsure of what brand, but it's NOT and open differential.

 

[Txstruck]

I believe its govlock but not sure of it.

 

[steelsoldiers]

Dana 60 trac-lock limited slip in the front, also known as the trash-lock.

 

[spicergear]

Track Lock, Yup...that's what it is. In stock form, they work good. Don't expect to have all four paws going with 40" swampers or anying with hunky tread.

 

[mangus580]

Whats the possiblility of a M1009 having something other than open diff in the front? Mine sure acts like it has something.

 

[85-m1028]

the np208 t-case is not a bad case the 2.62 low gear ratio is rescpectable and its aluminum case is alot lighter than a 205 but that doesn't make it weak the skid plate undr should ward off 99% of the potential damage you can inflict. the only reason I can see for running a 205 is if you plan on using a doubler with a 203 gear case for a 1.98+ 2.01 together gets you about 4 to 1 low gear very cool but expensive, all open diffs in the front on the m1009 unless a previos owner put something in. I think they did use extra heavy duty leaf springs on the blazer to get the 3/4 ton rating and the frame on the pickups were the dually frames so they are 30% stronger.

 

[mangus580]

Previous owner to me was the forrestry service in Arkansas... oh well, only one way to really know, jack 'er up!

 

[CUCVFAN]

This subject has always intrigued me (and annoyed me a bit, too). There's lots of mis-information out there, and every magazine article about CUCV's does nothing to clarify it. I have always assumed that the 8800# GVW of the M1008 made someone, somewhere refer to it as a 3/4-ton truck, and it seems to have stuck. Maybe the contract called for 3/4-ton trucks based on the old M880 contract, but the VIN says this was not what really happened, because it's 6th digit is the series and it's a 3 on any of the CUCV pickup variants, which is a 1-ton by GM's definition.

The pickups are rated as 5/4-ton trucks for the following reason: The GVW of the M1008 is 8800#. Subtract the curb weight (5900#) and you end up with 2900# payload capacity. The military allowed for 400# for a standard crew of 2 people. This means you have 2500# available to load as cargo. That's 1.25 US tons, or 5/4-ton. Plain and simple. I have a document somewhere that actually details this, but trust me, this is why they are called 5/4-tons. They can actually haul 1.25-tons. The M1009's on the other hand, only have a payload of 1200#, which is a little shy of 3/4-ton, but it is more than 1/2-ton, so I guess someone was feeling optimistic when they rated it.

Heck, my 1-ton Chevy crew-cab can carry 3000# of payload, but it's still a 1-ton truck (not a 1.5-ton) according to Chevrolet. The Amry could have called the M1028's ton-and-a-halfs, if they really wanted to. And they would have still been right!

The Dana 60 was not put into a 3/4-ton truck. If this was the case, then the rear was also a 1-ton transplant. The rear FF 14-bolts from 3/4-ton trucks have smaller (narrower) brakes than the ones in the 1-ton trucks (which the CUCV's have). The frame has the same dimensions as my civilian 1-ton frame, so I tend to believe the VIN when it's telling me these are 1-ton trucks. To this end, I would say that the only substitution was the NP208 case being substitued into a 1-ton truck. That's the only real piece that is out of place and would not have been found on a civilian 1-ton of the same era. And this was probably just a weight/cost saving measure for the contract.

Hope it helps!

 

[4bogginchevys]

I beleive it's an eaton posi unit. In another direction, for the civy gm 3/4 ton trucks, they took a 1/2 ton front diff and the bad boy 10.5" 14 bolt in the rear and basically equalled it to 3/4 ton

 

[Croatan_Kid]

Just for fun, I figured I would add that all solid front axles are, by design, full floating. This means that the axle shaft only transmits torque from the diff to the tire and does not support the weight of the vehicle at all.

 

[POOR WHITE BOY]

this subject has always intrigued me (and annoyed me a bit, too). There's lots of mis-information out there, and every magazine article about cucv's does nothing to clarify it. I have always assumed that the 8800# gvw of the m1008 made someone, somewhere refer to it as a 3/4-ton truck, and it seems to have stuck. Maybe the contract called for 3/4-ton trucks based on the old m880 contract, but the vin says this was not what really happened, because it's 6th digit is the series and it's a 3 on any of the cucv pickup variants, which is a 1-ton by gm's definition.

The pickups are rated as 5/4-ton trucks for the following reason: The gvw of the m1008 is 8800#. Subtract the curb weight (5900#) and you end up with 2900# payload capacity. The military allowed for 400# for a standard crew of 2 people. This means you have 2500# available to load as cargo. That's 1.25 us tons, or 5/4-ton. Plain and simple. I have a document somewhere that actually details this, but trust me, this is why they are called 5/4-tons. They can actually haul 1.25-tons. The m1009's on the other hand, only have a payload of 1200#, which is a little shy of 3/4-ton, but it is more than 1/2-ton, so i guess someone was feeling optimistic when they rated it.

Heck, my 1-ton chevy crew-cab can carry 3000# of payload, but it's still a 1-ton truck (not a 1.5-ton) according to chevrolet. The amry could have called the m1028's ton-and-a-halfs, if they really wanted to. And they would have still been right!

The dana 60 was not put into a 3/4-ton truck. If this was the case, then the rear was also a 1-ton transplant. The rear ff 14-bolts from 3/4-ton trucks have smaller (narrower) brakes than the ones in the 1-ton trucks (which the cucv's have). The frame has the same dimensions as my civilian 1-ton frame, so i tend to believe the vin when it's telling me these are 1-ton trucks. To this end, i would say that the only substitution was the np208 case being substitued into a 1-ton truck. That's the only real piece that is out of place and would not have been found on a civilian 1-ton of the same era. And this was probably just a weight/cost saving measure for the contract.

Hope it helps!

a men !!!!they should post this in all the 4x4 mags ,online sites , etc. Very helpful !. A true 1 ton also has the rear shocks mounted inside the frame rails - and the frame is thicker and taller .