Dodge 440 to 5.9 Cummins Diesel conversion

Started by Wantawinnie, October 16, 2012, 12:28 AM

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I made the decision to start the diesel swap in the Chieftain. Follow along and wish me luck.  D:oH! I will try to document all of the steps and problems encountered along the way in case anyone else has similar plans.

A little background. The Chieftain is a later build date 1973 Dodge RM400 chassis with the original 440/727 combination. The transmission is leaking out the front seal badly and the fluid looks and smells burnt. Also, the exhaust manifold gaskets are blown on the 440 and oil is leaking from about every gasket. Due to the plans for this RV and my access to the parts I decided the swap made sense.

The Cummins is a 5.9 6BT out of a 1989 Dodge Ram W350. Factory rating is 160hp at 2500rpm and 400 ft/lbs of torque at 1600rpm. It is a non intercooled version that I will be adding an intercooler to because of the rather heavy duty use it will be seeing. For the transmission, I will be using a diesel specific A518 out of a 1992 Dodge 4wd with a Cummins. In addition, a Gear Vendors overdrive will be mounted directly to the rear flange on the 4wd transmission with an adapter from Gear Vendors that replaces the transfer case.

Cummins diesels operate in a much lower rpm band than typical RV gas engines and, as a result, really need more gears to be effective. Use of an overdrive transmission is almost required if there is any hope of achieving typical highway speeds. The A518 I will be using has the same gearing as the original 727 it will be replacing from 1st through 3rd gears. The overdrive ratio is 0.69 and will achieve speeds between 60-65mph with the diesel. The Gear Vendor has a 0.78 overdrive and will be useful for splitting gears when hill climbing where the factory overdrive is too tall and 3rd gear is rpm limited to around 45mph. Double overdrive with both the factory and Gear Vendor engaged may be useful for interstate travel but will need to be determined once the RV is running and driving. I will run the factory overdrive off a simple toggle switch and engage and disengage it manually at the appropriate time. There are pressure switch options for automatic control of this but I have decided not to go that route. The Gear Vendor has the option of automatic or manual push button control.

Pulling the engine from the donor truck.

This is the front timing gear cover. There are a couple issues with the 12 valve Cummins diesels that should be checked. Especially when the engine is out of the vehicle as the repair is rather simple. One of these issues is a dowel pin under the cover that can vibrate loose and end up in the timing gears and cause serious damage to the engine. The term for this is KDP(killer dowel pin) and can be researched in depth on the web. The other issue is loose timing cover bolts that can do the same thing.

This picture shows the dowel pin.

The common fix is to either buy or make a metal tab to hold the dowel pin in place. I choose to make one as it is rather simple. I also Loctited all the timing cover bolts and tightened them back up.

The original exhaust manifold needs to be swapped out for one that drops the turbo down and toward the back in order to clear the floor on the Winnebago. This particular manifold and turbo came out of a 2005 Dodge Cummins turbo diesel. This may or may not be needed depending on the RV in question.

As with the 440 a front sump pan is required to clear the front axle on the Dodge chassis. Fortunately, the Cummins oil pan is reversible from front to rear. A front sump oil pickup tube is needed and is Cummins part #3920795.

Here is the oil pan installed with the sump to the front and the oil dipstick moved to the front location on the block.

This is the intercooler I found for the project. It is very well built and exactly what I have been looking for to fit in the narrow and tall front engine compartment of the Winnebago. It is a Denso unit that came out of a 1999 Mack Midliner with a 190hp Renault diesel. Core dimensions are 30.5" tall, 19" wide, 2.5" thick, and 3" inlet and outlets. This should do a good job keeping exhaust gas temperatures down.


Time to remove the 440 and 727 and prepare for the swap. Pic 1

Bumper is off, grille, and grille divider are out. Pic 2

Overflow tank, windshield washer resevoir, cross brace, radiator, and front crossmember are out. The radiator was a royal pain to remove. Pic 3

Upper shroud and fan are out. The exhaust is unhooked and the motor mounts are loose. A few more things to do but there's not much left before pulling the 440 out. Pic 4


This is totally awesome and something folks have been looking for for a long time.  Thanks so much for sharing this with us in such detail!

This is going to the top of the project board as a "sticky" and a referring topic is posted on the Dodge board.

:)   :)ThmbUp
1969 D22, 2 x 1974 D24 Indians, 1977 27' Itasca


That's pretty neat!  Can't wait to see more of the project, and the end results!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Wow! Sweet. We've been talking about a project like this for years on Classic Winnebago's. Thanks for taking the extra time to photograph all the steps. I think your going to have many members riveted to there computers every day from now until the project is done. Have at her, good luck and we'll be fallowing you as you go. :)clap
Oh! What are you going to do with the 440? She may have a few flaws I'm sure she's got some good parts on here. Hm?


Thanks guys, my wife and I are planning some long trips which is the real driver behind the conversion. Hopefully, this will cover the in and outs of this type of project so that if others are interested they can do the same.

The 440 still runs nice. I've got a couple older Dodge trucks and I plan to use it in one of them after degreasing and installing new gaskets.



Got everything unhooked from the engine and transmission. Removing the parking brake cable from the drum proved to be a rather stubborn and dirty ordeal. Everything else was fairly straightforward.

So, here is my version of pulling a 440 from a Winnie. :) Pic 1

It's out! I removed the Edelbrock carb and used a $12 carb plate from O'Reilly's and lifted it out. It balanced nicely using the rear of the three lifting holes in the plate. Pic 2

Last two pictures compare the Winnebago engine mounts and the 1989 to 1993 Dodge Ram Cummins engine crossmember. The similarities are very good and bode well for a bolt in swap.  :)clap


Makes it look a lot easier with a forklift in a well lit concrete floor!  Wouldn't be quite so fun in a gravel driveway or a dirt and root infested campground.  Still awesome, and I can't wait to see more of the project!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


This is the diesel A518 transmission. If you notice there is a mounting plate that gets bolted to the Cummins and then the A518 bolts to that. This is because there are many different mounting plates available for Cummins engines as they are used in so many different applications. This particular plate will mount 1989-1991.5 727 diesel transmissions and 1991.5-1993 A518 non lockup diesel transmissions only as the bolt pattern is specific. The later 47RH,47RE,etc. lockup transmissions use a similar plate except it is deeper to make room for the lockup converter. Pic 1

Here is the transmission setup I will be using including the Gear Vendor Overdrive. (Still need the adapter from trans to GV) Pic 2

Close up of the Gear Vendor Unit. Pic 3

This picture shows the mounting bolts of the A518. I will be using the front two bolt holes as they are nearly identical to the 727.(the bolt holes are about 1/4" wider on the 727) Pic 4

Here are some approximate measurements comparing the 440/727 and 5.9/A518 setups.

                                                                                                        440/727                                           5.9/A518

Centerline engine mount bolt to front of transmission                                       18.5"                                                19"
Centerline engine mount to fan mounting hub                                                  12"                                                15.25"
Centerline engine mount to front of fan                                                         15.25"                                             19.25"
Bellhousing to centerline transmission mount                                                  20.75"                                             20.25"
Transmission total length                                                                            30"                                                 31.5" (no GV)
Centerline engine mount to centerline transmission mount                                39.25"                                             39.25"

Looking at the numbers we can see that if the Cummins mounts in the exact same location using the existing frame mounts it will extend 4" forward of the 440 and the transmission mount should fall in the same location. Again these are approximate and it will have to be installed to ultimately find out.

The biggest issue is trying to keep the existing radiator mounting setup in place. There is a lot going on in that area and I don't want to re-engineer that if it can be avoided. In order to do this the simplest method is as follows. The length of the 440 with fan installed is the same as the Cummins without a fan installed. This is good because it will physically fit behind the factory radiator as long as the fan is removed from the Cummins. Electric fans will be used instead of the Cummins clutch fan.


Good stuff Mate, all though fork lifts and concrete floors are cheating. :laugh: Keep up the good work. Look forward to your posts. Nice 68 Chevy in the back ground. :)ThmbUp


Here are a few specifics on the Cummins setup from the 1989 Dodge Ram.

The diesel fuel system uses a fuel pump on the driver side of the block very similar to the big block. A return line to the tank is needed and you can see that to the lower right of the picture. The large sensor on the right top is the coolant sensor location. The large tube coming out of the block is the breather setup commonly in the valve cover on the big blocks. Pic 1

This is a picture of the VE injection pump used in various forms from 1989 to 1993. All are pretty similar for the most part. The wire with the crimped on connector runs to the fuel shutoff solenoid. 12V power to this solenoid and to the starter is all that is needed to get this engine running. The solenoid can be eliminated with a manual cable hooked to the lever directly to the left of the crimp connector. The round piece on the bottom with the fuel line, extra port, and electric connector is known as the KSB. In short, it adjusts timing during engine warmup. On the non intercooled 89-91.5 motors adding 12V power retards timing for normal operation and advances it during warmup. This is controlled by a box located in the Dodge truck. It is not really required and simply tying the fuel solenoid and KSB together to 12v power works fine. Note: On the 91.5-93 intercooled engines the KSB does the reverse, no power retards for normal operation adding 12V power advances the timing. Pic 2

BTW: The wire throttle connector is a farmer's quick fix and not factory.

Last pic is the vacuum pump and power steering pump. Diesel engines don't produce vacuum so this pump allows vacuum accessories to still be used. Pic 3


Quote from: ClydesdaleKevin on October 19, 2012, 10:08 PM
Makes it look a lot easier with a forklift in a well lit concrete floor!  Wouldn't be quite so fun in a gravel driveway or a dirt and root infested campground.  Still awesome, and I can't wait to see more of the project!


I figured there would be some razing from you guys about my engine hoist.  :P


LOL!  Where in tarnation did you find a used Gear Vendor unit?  I've been looking and can't find anywhere, even with a national Craigslist search.  The project looks great so far!  And it looks like you are moving right along at a fast pace.  You'll be done before you know it!  Can't wait to hear how she performs both power wise and fuel economy wise.  And heck, its an older diesel, right?  Which means if you wanted to you could run it off biodiesel or even french fry oil with just a couple of minor modifications.  Sweet!

Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Found it on Craigslist, came with a rebuilt big block 727 and a set of 440-3 headers. Shipped to my door for less than $800. The Chevy Turbo 400 setups show up from time to time. There is an adapter for a Cummins to that as well. :)ThmbUp

The diesel is old school and veggie friendly.


If you pull this off and get decent mileage with it I can see a gold rush on Diesels. Really appreciate you taking the time to bring the rest of us along on the journey with you. :)ThmbUp


No problem, I am a huge fan of these old Winnie's and the early Cummins trucks. Seemed like a match made in Heaven.

BTW: What's this "If" I pull it off stuff? :D


Quote from: LJ-TJ on October 20, 2012, 04:17 PM
WHEN you pull this off and get decent mileage with it I can see a gold rush on Diesels. Really appreciate you taking the time to bring the rest of us along on the journey with you. :)ThmbUp
Fixed :-)
Don and Mary
2000 TC1000 Bluebird bus conv.


It might not look like much but the better part of the afternoon was spent cleaning the engine compartment and underside of the Winnie of 40 years worth of grease and grime. The transmission area was quite a mess from the leaking seal. Cut out the rest of the exhaust crossover and muffler also. Pic 1

Here are a few pictures of the A518.

The bracket is the mount for the Dodge truck shift lever. The electric plug in on the right is for the overdrive. Everything else is typical A727 stuff. I think the tranny line fittings are larger though. Pic 2

After removing the bracket it appears the A518 in the Pic 3 has a mounting ear nearly identical to the A727 in the last picture. Hopefully, this means the factory shift cable should be a bolt in deal.


I did have a little trouble bolting up the transmission tonight. It is not a big deal but will slow me down for a day or two. I bought an aftermarket flexplate because I didn't have the original and they are prone to cracking. Well, the new one is thicker than the original which makes it stronger but also reduces the clearance to the torque converter. Because of this it does not spin freely and will damage the front seal on the transmission if not corrected. The cure is to either buy an aftermarket bellhousing spacer to move the transmission back about an 1/8" or make one myself. I will call tommorow and see how long it would take to get one. Using factory parts would have not required this.

The pressure line on the power steering will also need to be either made or find an adapter fitting for the original hose. The pump on the Cummins has a different fitting than the 440 unit. The original return hose will work fine as is.


I have a friend that does these type of challenges. I nicknamed him "Brain". You my friend have earned that right..from now on you are "Brain" :) John

Check it-Boom


LOL, we will see how smart I am shortly. If I mess up you guys will be the first to know.

I ordered the transmission spacer from PATC this morning. It is part# BHS and cost $69.00 + shipping. It will probably take a couple days to get here so I will find some other work to finish.

I checked out the fuel lines on the diesel truck and they are 5/16" feed lines which is the same as the Winnebago. From looking it over the plan is to remove the rear tank feed line from the dual tank transfer valve and connect a new line up the driver side for a few feet to the diesel pump. Another 5/16" line runs from the charcoal canister all the way back to the rear tank. I am hopeful this can be used for the diesel return line. 


Good read. :)ThmbUp Looks like your doing an excellent job.


Some more progress today. This is a little info on getting the Cummins to work with the Winnie gauges.

Here is the factory coolant sensor removed leaving a 3/4" pipe thread hole. Pic 1

Went down to the local hardware store and found a 3/4" plug with the correct 1/8" center thread to adapt the original 440 sending unit for the factory guage to work correctly. Here it is re-installed. Pic 2

Next up is the Cummins oil sending unit located on the driver side above the engine mount. Pic 3

Unplug the Dodge wiring that will no longer be needed. The sending unit is 1 1/16" and requires a deepwell socket to remove. I borrowed a special socket from a friend made just for these types of newer sending units.   

The 440 sending unit screws right back in the Cummins port and will allow the factory oil gauge to read correctly. Pic 4


The next step was getting the throttle cable, kickdown, and shift cable to work. I have been dreading the kickdown assembly as the original Cummins cable was missing because the donor had a 5 speed transmission. There is no bolt on deal for this anyway if the original Winnebago throttle cable is used. For simplicity and cost I modified the original 440 components to work on the Cummins.

First, I modified the original throttle assembly by bending the mounts that go to the 440 intake in order to work on the Cummins throttle mount. I then drilled the following 2 holes after measuring the distance needed using the original throttle cable. This mounting dimension was 6.5" from the Cummins idle postion to the center of the throttle cable mount on the original 440 bracket.

For clearance and alignment I flipped the swivel and drilled out the hole. The slide rod was bent for clearance as well. The eyelet on the end of the throttle cable was also drilled out slightly larger to slide over the Cummins throttle assembly. You can see the spacer added to level out the bracket as the Cummins assembly slants downward to the rear.

The Cummins is longer than the 440 and a extension was required. I found a 4bbl kickdown rod in my parts stash off a 1976 Dodge 200 440 4bbl. It is a pretty common item and something similar is easily found in any junkyard. I flipped the rod around and put the fixed end in the swivel bracket and then connected the adjustable end to the factory kickdown rod off the original 440. The return spring brings the kickdown lever back into position after letting off the throttle. Pic 1 is the completed assembly.

Down on the transmission side there are some changes needed as well to get the original shifter and kickdown to work properly. Carefully remove them by loosening the locking bolts and then sliding the levels off. The lower shift lever is retained by an E clip in addition to the bolt.

The A518 and 727 kickdown levers. Pic 2.

The A518 and 727 shift cable levers. Pic 3.

The original 727 levers bolt directly on to the A518 without modification. Pic 4