Cummins 4BT & Diesel Conversions Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter #1
A '99 4x4 extended cab 5-speed.
Fired up my motor today bolted to a pallet in the garage - love the sound!
OEM was 3.9l V6 and I'll retain the 5-speed transmission (154,000 on original clutch so it's not one that's been abused)
I got the motor last fall but there were several things I had to do to it - turbo was locked up from where water and dirt had entered the exhaust side as it sat in a hangar and gunked up the blades. Took it all apart and cleaned it up - no play. The lift pump was cracked like it had had water in it. It had cracked along the upper seam and I chose to get a used one rather than to try to weld that one back together, though I will have a spare soon. I'm not sure this motor has ever run given the spotless interior of the valve covers. Nameplate is a '99 Reman CPL2302 which came with a Bosch A-pump/RSV governor combo. Had a PTO on the front of it when I got it. It supposedly came out of an airport deice truck and as such it didn't have an alternator, had an SAE3 flywheel housing (minus flywheel and starter) and was mounted on four sturdy rubber-isolated steel legs. Best I can tell it was designed to drive only the pump on the truck as most deice trucks have two engines - one for the drivetrain, the other for the pump. I have yet to work out the throttle cable hookup details (there's only a lever on the pump right now) and fuel shutoff solenoid setup (though a manual cable might work). Probably have yet to work out lots of other stuff I haven't thought of yet too...!
Anyway, here's the plan:
- stock AX-15 using NV4500 bellhousing and clutch/pressure plate with an adapter plate(read good things about Advance Adapters plates)
- 3-inch exhaust
- modified oil pan for front driveshaft clearance
- stock suspension
- bread truck gel-filled motor mounts
- 3200rpm spring (stock 3.92 gears need about 2700rpm for 70mph)
- 3.72 or 3.55 swap in the future depending on how this first chapter goes...
Questions? Comments?
 

·
Registered
Joined
·
13 Posts
No comments, but Im excited to start following this. I'm in the "research" phase to do a very similar swap. Goodluck! Keep the build thread updated!
 

·
Premium Member
Joined
·
2,974 Posts
You will want to look for 3.55's. Unless you plan on running a big tire. What NV4500 bellhousing are you going to use?
 

·
Registered
Joined
·
49 Posts
Discussion Starter #5
I have a Dodge Cummins bellhousing I'll be using off a '99, I think.
I'm aware the AX-15 is a bit undersized for burnouts/cranked up motors but I can't see swapping it out until I need to - it's really not a big job if it lets go... Right now I'd rather continue driving my truck like I have for 12 years than part with $1500 for an overbuilt tranny for my motor. I'll keep the post updated as I get it going so we can see how the AX holds up.
On the axle ratios, I found a site where you can enter gear and axle ratios and tire sizes and see what RPM the motor will be at at various speeds. Planning to keep my 31.5's so the 3.72 will put me just over 2300 at 70 if I remember correctly - that's why I was thinking about that one. But the Dakota did come with 3.55's so those would be straightforward - we'll see how the 3.92's do first...
 

·
Registered
Joined
·
49 Posts
Discussion Starter #7
Slight change of plans - picked up a 4x4 NV4500 with bellhousing/fork for $900 the other day so I've changed my plan a little. Got to thinking about that ax-15 - it has 155,000 on it, and if it goes then I'll have a $300 adapter plate that will be impossible to get rid of and I'll probably not want to replace it with another ax-15. I'll set my ax-15 on the shelf and put it in another little truck someday if the opportunity arises. It really has been a good little transmission in the Dakota.
I've just not had the time to work on the project lately. Inspection sticker expired on the truck 2 days ago so my plan is not to get it inspected again until it's burning diesel!
Patrick
 

·
Registered
Joined
·
49 Posts
Discussion Starter #8
In the garage with the old motor ready to lift out in the morning.
Today I pulled the front bumper, lights, radiator and crossmember, alternator, compressor and lines, power steering pump, exhaust and lots of electrical connections.
Also pulled all the motor mount bolts so after disconnecting the fuel lines and starter wires it'll be ready to remove tomorrow.
I'll spend the rest of the day tidying up the engine bay - a good bit of rust to knock off from these WV winters. Also might try to stuff the transfer case and tranny in for a test fit. I'm waiting on a new bearing to complete the swap of a NP241 input shaft into my NP231. I've also got a 2wd extension housing that I'm going to have to tap holes in to mount the transfer case shift lever so I'll have to look at that. Have to check out the differential support system and see how to brace it without the motor. Sounds like a full day tomorrow... I'm thinking there are going to be several of those before this thing moves again! I have spent the better part of a year working on getting the motor running - bought several parts from members of this site and have done lots of research on here!
A couple of weeks ago I pulled my bed and POR-15'd the rear part of the frame. While I was under there I put in a fuel return line and replaced a nearly broken leaf spring shackle.
 

·
Registered
Joined
·
314 Posts
good choice on the NV4500, its a bit of a tight fit, but well worth it. Your going to find out that the shifter is going to come through body very close to the dash, but with a good bit of bending it will shift just fine. Are you going to do a body lift?
 

·
Registered
Joined
·
355 Posts
Welcome to the Dakota 4bt club I second the choice on the 4500 trans looking forward to seeing this project as it goes.
I don't even think of mine as a truck anymore it's just something to set in the shop in my way.
when I'm not working on it.
be prepared to spend plenty of time in the shop:D
 

·
Registered
Joined
·
49 Posts
Discussion Starter #11
The motor, trans, and transfer case rest in their new homes tonight. Not permanently, as the only things holding them in place are jacks and stands, but they look happy, though tight, in there. It's been a busy couple of days - 4 so far - but I've been surprised by the amount I've been able to get done. Old transfer case, motor and transmission out and new one mocked in place. Not too shabby for a week of vacation working solo. Tomorrow's an Uncle Sam flying day then three days of call for my other job so I'll probably stall at this point until next week. Gives me some time to craft some ideas to get the stock crank and camshaft position sensors working so my tach and electrical charging system will work.

Speaking of the charging system - I'm thinking that a notched ring on the front of the pulley will work for the crank, as some have done. Camshaft appears to be a magnetic sensor that is active for 3 consecutive cylinders then inactive for the next three on the v6 - basically it's on half the time. Not sure if the PCM correlates the results of the two sensors in some way. Nor am I sure how I'll go about getting this cam signal yet. Any insights are appreciated.

Anyone with a 4x4 done this swap with the NV4500? The length of the transmission is making me think I'm going to have to do some unplanned mods to the driveshafts - if not, the trans is going to sit very far forward and require a honking bend in the shifter, like pigeon said, and possibly some sheet metal removal from the front of the tunnel. Is yours a 4x4, pigeon? If so, did you have to do driveshafts? I'm using my original NP231 case with a new input shaft to match the diesel spline count.

Pigeon, I'm not thinking about a body lift yet - don't even know what's involved, actually - my truck has been basically bone stock since I bought it in May of 1999. Is that an easy project? I've wanted a suspension lift, and considered a solid axle for this project but thought it beyond my experience level for now. I've always done brakes, fluids, and minor repairs (which there have been relatively few) but this is a huge step for me and one I wouldn't have jumped into had I not discovered this site. Learning lots and liking the new tools I'm collecting along the way!

More to come,
Patrick
 

·
Registered
Joined
·
49 Posts
Discussion Starter #12
Things change...

Pigeon,
2-inch body lift complete - really opened up the workspace for me up front. A few pics of the progress for those that care...

http://s1192.photobucket.com/albums/aa323/cpberry2/The Transformation/

Welded up the two lower motor mounts today. Also dropped off the rear driveshaft to have about 4.5 inches removed to make room for the NV4500. It was either that or hack up the sheet metal to move the whole setup forward and I figured $40 to shorten the shaft was money well spend. We'll see about the front one later.

Coming along nicely - hope to complete the motor mount setup tomorrow and then start looking for places to hang the differential.
Patrick
 

·
Registered
Joined
·
49 Posts
Discussion Starter #13
Took the first trip around the block today!! Actually took three trips around the block since I was having such fun. Several updates since my last post. Had to hack up the old oil pan to get the front diff in and keep the independent front suspension and four wheel drive. Old pan would not seal well after the mods and it decreased the capacity a bit - probably not significantly, but enough that I wasn't thrilled with it. I probably could RTV it and make it work but have decided to change my direction. Since I never liked the IFS anyway I have decided to just go with 2wd for now, and a new unhacked oil pan, and keep my eyes open for a nice front solid axle with a 3.55 ratio for fuel economy. Now I have to tackle the wiring - can't get the tach working though I have it wired the way some have done on here and thus the alternator circuit won't charge... But with 9 days off the end of the month I hope to have it on the road by 1 April. It's been fun and I've learned a lot - thanks mainly to the posters on this forum.
 

·
Registered
Joined
·
49 Posts
Discussion Starter #14
Well it's been on the road for a couple weeks now and what a hoot to drive! Initial impressions?

The RSV governor is neat - like cruise control, as some have mentioned. it adds fuel to keep constant rpm as load changes - when you come to a hill it adds fuel to keep the speed up.

The NV4500 is much more of a truck transmission than e smooth AX-15 I had in the Dakota before. 1st gear is useless for daily driving.

I have a 6bt resonator to install - 4 ft of 3" flex isn't enough to drive for any distance without earplugs.

Quite pleased with the swap - lots of loose ends to tie up but I've got about 200 miles on it and love it so far!

Patrick
 

·
Registered
Joined
·
49 Posts
Discussion Starter #15 (Edited)
After 1800 miles - first mileage test included about 300 miles pulling a 2400# trailer back from WV to Waxhaw NC and yielded 23 mpg so I think 25 mpg unloaded is quite likely.
I lost fluid in my TC and melted the range fork - a tear down and a $50 fork and a $20 seal kit and it's back on the road. I just got a 3-gauge pillar pod and will be filling it shortly. I still have a box of Dynamat to install at some point but a Ram 4" exhaust pipe fit well and quieted it down quite a bit.
Also bought a '93 D250 with a Cummins so it's been getting some of my playtime as well.
Other notes...
Got the tach and associated systems working initially but it has since quit so I put in an external regulator for the alternator and will research it later. Also my fuel solenoid quit on me so I'm manually operating the lever until I can focus on whether it's internal to the solenoid or a weakness somewhere else in the wiring. It seemed it was draining my battery also so I suspect something in the wiring.
 
1 - 15 of 15 Posts
Top