New project - Dodge Class A Motorhome 4x4 conversion

[G35Vortec454]

I've just acquired a 1977 Dodge Class A 25-ft motorhome with a 440 motor and 727 tranny in a M400 chassis, 12k GVWR. I will be installing a GearVendor in it soon. Later, I want to convert it to 4wd like I did to my 21ft GMC motorhome, using a Dana 60 or 70 for the front axle with 4.56 or 4.88 gears, and giving it the appropriate lift for ground clearance. The motorhome will see moderate/medium trails, including Baja dirt/rock roads. I am handy in fabricating and welding; howevcer I'm new to Dodge stuff; I know there are Dodge guys here with lots of knowledge.

Questions:
1. What kind of Dana 60/70 should I use (are Dodges passenger side drops?) What are my options? Can I use a Ford Dana 60/70 driver-side drop? Can a Rockwell axle be used instead?
2. What transfer case will I need?
3. What adapter will I need?

Art

 

[chasespeed]

My Ram is driver side drop.

If you have the 727 I believe you can look at the NP208, and the D300....

Chase

 

[G35Vortec454]

I got something from another forum that the ideal way would be to get the tail piece from the 727 tranny from a 4x4 80-93 Dodge truck and put it in MY A727. The reason for that I'm told is that the A727 that I have is a motorhome HD version unlike the pickup truck trannies. I'm also told that to be able to swap the tail, my tranny will have to be disassembled due to the tail going in first in the assembly sequence.

It was also suggested that an NP205 be used due to the torque and weight requirements of the motorhome.

Anyway I'm learning a lot fast!

 

[dsw4x4]

I would say steer away from a rockwell for this conversion first off you will need to lift the rig real high to clear the hugh diff, second you will not have the gear ratio you are looking for in a rockwell and third the straight cut gears that a rockwell uses wine at highway speeds. I only have experience with rockwell 2.5 ton axles they make some smaller axles that would work better.
I would also not use a dana 300 it is way to light duty of a t-case for that application. I would use a 205 with a truck adaptor. Going this route will be cheap, easy and bullet proof.
Derek

 

[G35Vortec454]

Thanks Derek for the advise.

At this point, for the axle, I'm looking into the new Dana Super 60 axles that are used in the 2005-up F450/550s; I think I'm gonna go with 4.3:1 gears. They have a GAWR of 6K-7K lbs. One dealer of Ford Racing Perf Parts sells them for $1665 without the rotors and calipers. I'm waiting to find out the width (wms-wms) of the DRW axle hoping it will be wide enough for my Class A motorhome. It should be easy to put leaf spring pads on the axle and do away with the coil spriing and radius arms brackets (the motorhome has front leaf springs).

For the transfer case, I'm now in the lookout for a divorced NP205 (Ford application, driver-side).

Art

 

[spencyg]

It seems at first glance like that rig will self distruct the first time you twist the frame up. It was never designed to take the kind of use you are proposing, and everything from the frame to the driveline to the galley cabinets will potentially come apart. Purpose built offroad campers in that size range have 3 point floating boxes to address the reality that the frames on larger trucks are meant to twist. The camper on your rig looks like it isn't meant to do that. I would think very long and hard before persuing this idea any further. It seems like the engineering gods will be against you 100% of the way.

Just my $0.02.

 

[Gunracer1]

i would have to agree with spencyg, it takes a lot of work to get a big rig like that to take the abuse.

 

[G35Vortec454]

Spencyg and Gunracer1, I appreciate your concerns and advice. This rig won't see the same "abuse" that my GMC UAV (my avatar) has seen in Baja lately (if you've seen the photos and YouTube) conquering 14 miles of the most difficult trail in Baja. But in light of your comments, I think I'll consider beefing up the frame and cabinet attachments, just in case I get tempted into "challenges" later. I'll also read up on 3 point floating boxes. I figure that if my 21ft GMC motorhome (10500 lbs UNIBODY)could do the DIFFICULT trail without too much damage, that the 25ft one (12000 lbs on a C-FRAME) would be able to do a MODERATE trail similarly. They both have fiberglass molded bodies. Further, I'm not trying to build something that will last forever; it's a toy, an experiment, a lifetime (maybe) project-in-progress, something that would keep the little child in me occupied on the weekends after every trip, if you know what I mean. Of course that outlook may change.

 

[xped]

there are alot of 4x4 Dodge Pathfinder conversions of your vintage out there. You could take the whole drivetrain or adapt to your needs. They only use a dana 44 up front and most have the fulltime 203 tcase with a driverside drop. They use a special adapter to allow a Ford spec 203 to mount to the 2wd trans, this may come in handy for you. I would recommend the Dana 60 front and a 205 tcase or better.

 

[G35Vortec454]

xped, thanks for contributing.

I have the Dana 60 under my GMC dually motorhome and I've concluded it would be too narrow for the Class A motorhome. Therefore I am looking into the wider (full 15-inch wider) Super Dana 60 in the 05-up F450/F550s.

And of course, I'll be using a divorced NP205.

 

[thedjjack]

I would go Divorced 205

I would run a divorced 205 (ford or dodge (opposite side depending on axle you go with)).

Simple, 205 are bullet proof (could use water for oil in them!)

This is what I ran in my Jeep FC with Mercedes OM617.