Looking at a 1994 3500HD with Monroe 4WD Conversion

[vintageracer]

I got this crazy idea causing me to look at a cab/chassis 15000 GVW 1994 Chevrolet 3500HD 6.5 Diesel Dually with a Monroe 4WD Front End Conversion from new that is for sale locally. Dana 80 rear with Dana 70 front.

Yes I know about all the 6.5 diesel/4L80E transmission issues however while not a big powerhouse it should make a good ole diesel for a composite box conversion mounted on the back. Length of the frame from the back of the cab to the end of the frame rails is 124 inches which give a LOT of room! Maybe too much room for a box!

Truck has 130K miles, winch bumper on the front with power steering, 4 Wheel Disc brakes, A/C, tilt and cruise.

Problem is the truck has 5.13 gears!

Current tires are original 245/70-19.5 which puts RPM @ 60 MPH in overdrive at 2350 RPM. That's a no go!

Swapping to singles all around and going up to a 40 inch tire which will fit drops RPM at 60 MPH to 1940 RPM, 2100 RPM @ 65 MPH and 2300 RPM at 70 MPH which is manageable. 37 inch Humvee tires/wheels put the RPM's pretty much in the middle of the above RPM numbers.

Obviously I will never be anywhere near the total GVWR of the truck. The tires would be the limiting weight factory.

Asking price is $4500 which I believe is overpriced given the fact that the paint is schidtt, will need a new set of expensive wheels/tires just to begin to work for what I want, the age of the truck and it's another damn project.

Attached are 2 pictures of a SIMILAR TRUCK with a service bed. Imagine the same truck without the service bed. These are NOT ACTUAL PICTURES OF THE TRUCK I am looking at.

This leads to my question:

Opinions on this type of cab/chassis truck retaining the 5.13 gears, installing large singles for tires/wheels for composite box conversion on the back for on and off-road travel ?

 

[shrineboy]

I got this crazy idea causing me to look at a cab/chassis 15000 GVW 1994 Chevrolet 3500HD 6.5 Diesel Dually with a Monroe 4WD Front End Conversion from new that is for sale locally. Dana 80 rear with Dana 70 front.

Yes I know about all the 6.5 diesel/4L80E transmission issues however while not a big powerhouse it should make a good ole diesel for a composite box conversion mounted on the back. Length of the frame from the back of the cab to the end of the frame rails is 124 inches which give a LOT of room! Maybe too much room for a box!

Truck has 130K miles, winch bumper on the front with power steering, 4 Wheel Disc brakes, A/C, tilt and cruise.

Problem is the truck has 5.13 gears!

Current tires are original 245/70-19.5 which puts RPM @ 60 MPH in overdrive at 2350 RPM. That's a no go!

Swapping to singles all around and going up to a 40 inch tire which will fit drops RPM at 60 MPH to 1940 RPM, 2100 RPM @ 65 MPH and 2300 RPM at 70 MPH which is manageable. 37 inch Humvee tires/wheels put the RPM's pretty much in the middle of the above RPM numbers.

Obviously I will never be anywhere near the total GVWR of the truck. The tires would be the limiting weight factory.

Asking price is $4500 which I believe is overpriced given the fact that the paint is schidtt, will need a new set of expensive wheels/tires just to begin to work for what I want, the age of the truck and it's another damn project.

Attached are 2 pictures of a SIMILAR TRUCK with a service bed. Imagine the same truck without the service bed. These are NOT ACTUAL PICTURES OF THE TRUCK I am looking at.

This leads to my question:

Opinions on this type of cab/chassis truck retaining the 5.13 gears, installing large singles for tires/wheels for composite box conversion on the back for on and off-road travel ?

That is a lot of axle. It sounds like what you’re thinking about would be a big project no matter where you started. I put 5.13s in my suburban specifically because of the no power house 350, with 37s. 65 mph is about as fast as I like to go anyhow. I’ve been running these for about 3 or 4 years and I don’t regret doing it. In my opinion, I wouldn’t let those gears be a deterrent.

 

[twodollars]

I'm a big fan of the 6.5 and 4l80 combo. 6.5 can easily bump up to 250hp if the bottom end is in good shape. That will get you about 500 lbft too.

 

[TwinDuro]

Hmmm, interesting! I hope some folks with 3500HD experience chime in!

Since it's a 1994, would that be the last hurrah for the mechanical 6.5TD or was the the first year of the electronic 6.5s?

I have to admit that I've lusted after the GMT400-based 3500HDs with the 4x4 conversion. Just seems like a super cool, simple, heavy duty rig. There was a 2001 3500HD with the 4x4 conversion, 8.1 gasser and NV4500 for sale out in my area awhile back. It went quickly!

 

[arveetek]

I'm a big fan of the 6.5 and 4l80 combo. 6.5 can easily bump up to 250hp if the bottom end is in good shape. That will get you about 500 lbft too.

Ditto. I've got 368K miles on my 6.5L/4L80E. The trick to longevity on these engines is not trying to tow extremely large loads. Moving a vehicle around, even a heavy one, is where they work best. But trying to tow large trailers works them to death.

Casey

 

[twodollars]

If it's a 1994, that should be an ds series pump, but unique to that year. The pcm should have a replaceable e prom, and any decent tuner should be able to accommodate a post 1994 pump, which will make getting a rebuild easier.

 

[Regcabguy]

They're actually louder than a 24v Cummins. No sneaking up on anyone.

 

[DirtWhiskey]

Miss my old 6.2 with the banks. One of my favorite hunks of metal. The 6.5 is a fine engine if you take care of it. Those old 3500HDs are cool and I rather enjoy the old square body. $4500 is a bargain if the frame and body are straight and I'll be mad if you don't buy it.