M1008 cucv- thoughts?

[SAFD3160]

So guys here's the situation.

I can get a cucv in decent shape (no rust, interior in tact) for around $3000-3500 from a military base mechanic I know.

I really want to use it as a daily driver. I am a full time college student and I drive to school and work everyday round trip of about 60 miles

I know they get horrible milage, so I want to swap the TH400 with a TH700r4 or an NV4500. My main focus is fuel economy. And a little sound deadening. So my questions are...

1. Is this a viable option as a daily driver?

2. Which tranny is better to have?

3. What options are the best for maximum fuel economy? I know the 6.2 is a dog in heat, but for what I will use it for it's got plenty of power.

Any ideas would help guys! Great forum!

[AKMark]

Drive it as it is. You may be surprised at how well it does.

Yes it won't have the top speed a truck with overdrive and 3.73 gears would have, but I bet it will be fine, unless you want to drive 70 mph.

Turbo 400 is a way better transmission than the 700R4, so if it isn't working out, I would swap axles to something with anywhere from 3.08 gears up to 3.41 gears. That would give you a final ratio closer to the overdrive of the 700R4, while running a nice stout transmission. I should note, that the truck will probably be a dog with the above mentioned gears.

[SAFD3160]

What gas milage do you think I could get out of a turbo 400 and 3.08 gears?

[john8662]

Gear ratio swap will be costly. As you've got two axles to swap gears on.

The 14 bolt Full Floater 10.5 rear will accommodate 3.23 on up, the Dana 60 front will accommodate 3.56 on up. Most likely you'll find a matching ring and pinion to go to 3.73 in both housings.

Even with a TH700R4 the 4.56 gears that the M1008 has are still killer, but more manageable.

They have a 235/85 R16 tires on them right?

With the 700R4 in OD you'd see 2400 RPM at 70 MPH. Probably around 15-16 MPG.

The TH400 you'd see ~3500 RPM at 70 RPM (engine isn't happy at this RPM). This trans doesn't have OD or a locking converter, it's a dinosaur.

[SAFD3160]

Is it possible to hit 20-25 mpg?

[john8662]

20 maybe if you change the gears and add an overdrive transmission.

A Gear vendors Overdrive unit maybe the ticket there too in conjunction with an overdrive transmission (double overdrive).

If you want better mpg I'd suggest an M1009 Blazer, replace the trans in one of those with a TH700 and you'll have 20 MPG (they already have 3.08 gears).

6.2's can get 20-25 MPG in 1/2 ton 2WD trucks, not 1.25 TON 4x4's, ya know.

J

[HH]

Where are you in Wisconsin?

[SAFD3160]

Midwest

[AKMark]

20, no. My buddy has one, stock it gets about 15 on the highway. He keeps it below 62 mph.

There's no guaranteed way to get in the 20's. I've had a few that did, and a few that didn't. One with 3.41's and a 700R4 that got 24 all the time. One with 3.73's same size/type tires and a 700R4 and it got 17. Rebuilt the motor and after break in it still did no better than 19.

Dad had a 3/4 ton with a 4-speed overdrive manual, (odd ball) it got 25 or better. But was a 4x2.

Stick shifts seem to do better, but a lot is in how you drive it and how healthy the motor is.

[SAFD3160]

Dang I'd settle for 18! 10 mpg driving 60 mi round trip is not a good option

[AKMark]

The only time I've gotten 10 with a 6.2 was when I was pulling a 10K trailer.

Even the Dually's with 4.10's, 32" tires, and no overdrive typically got better than 15 on the highway.

[AKMark]

My 84 K-20 Burb with 32's got 17 hwy, no overdrive and had 3.73 gears.

I put 36" tires on it (no lift) and that dropped to about 15.

I put 4.10 gears in it (swapped a set of 1 ton axles in place of the 3/4 tons) and the mileage jumped back to 17 hwy.

Now the same engine, and axles are in my K-5 coupled with a SM465 (4-speed no overdrive manual) and with the 36's, a 4" lift 12K winch and other fun goodies, I can get 18 depending on my top speed. She can still run over 65 mph no problem. But most of her use is offroading at speeds under 10 mph, and she sips the fuel, compared to the 4.0L gas engine Jeeps that I typically roll with. I use 1/4th to 1/5th of the fuel during offroading than the gas motors regardless of size. I could run 4.56 gears in my K-5 and it would probably help me out a bit in the low speed stuff, but hasn't been an issue. My K-5 typically get's trailered to the trails, as the 36's are old Humvee tires that aren't so friendly on the highway. They've got custom grooving to make them better in mud..... :)

The 99 K2500 6.5 in my signature get's 19 hwy even with 33" all terrain tires and 4.10 gears. However, increase the speed to 70 and it drops. No matter what you drive.

[SAFD3160]

My 84 K-20 Burb with 32's got 17 hwy, no overdrive and had 3.73 gears.

I put 36" tires on it (no lift) and that dropped to about 15.

I put 4.10 gears in it (swapped a set of 1 ton axles in place of the 3/4 tons) and the mileage jumped back to 17 hwy.

Now the same engine, and axles are in my K-5 coupled with a SM465 (4-speed no overdrive manual) and with the 36's, a 4" lift 12K winch and other fun goodies, I can get 18 depending on my top speed. She can still run over 65 mph no problem. But most of her use is offroading at speeds under 10 mph, and she sips the fuel, compared to the 4.0L gas engine Jeeps that I typically roll with. I use 1/4th to 1/5th of the fuel during offroading than the gas motors regardless of size. I could run 4.56 gears in my K-5 and it would probably help me out a bit in the low speed stuff, but hasn't been an issue. My K-5 typically get's trailered to the trails, as the 36's are old Humvee tires that aren't so friendly on the highway. They've got custom grooving to make them better in mud..... :)

The 99 K2500 6.5 in my signature get's 19 hwy even with 33" all terrain tires and 4.10 gears. However, increase the speed to 70 and it drops. No matter what you drive.


I'm actually debating on to get a jeep or a cucv. I wanna lift the jeep 2.5 inches, and with a tj I'd hit maybe 12 mpg with 33's. with a jk a little better, but not as good as a cucv 6.2 with a o/d trans. What to do!

[wpdozer]

I get almost 25 MPG with a monster trans super duty 700-R4 in my M1031 with 4.56 gears and LT/285/R85-16 tires on it.