700r4 or NV4500? Newbie here looking for direction.

[Farmboy0007]

Hello all, long time reader. Looking for a bit of direction here.

I have a 79' FJ40, 350 V8, and stock past that. Currently the 350 has eaten a valve, and I am pondering the future of the Cruiser.

First of all, money is of some object, but not to much, I am willing to take the time to wait, save, wait, save, and eventually get what I want, a small, hellauciously stout, bomb proof rig.

I am planning on a Cummins 4BTA as the replacement engine.

Transmission, ?????

Atlas II TC (the 4-spd 10.4:1)
Diamond axles, 2.77:1 (probably), want air lockers, and hoping for a run flat air system(lofty I know), 4 wheel disc brake. aiming for an 8 lug full floating setup, 4-link coil overs, 35" tires.

During the winter I eventually hope to get Mattracks. Probably about the only way I will get the wife out and into the middle of nowhere surrounded by snow.

So the transmission . . . .

I am torn between the auto or manual.

I like the manual, feel of control, simple, super steep or on its side doesn't create a problem. Yes, I can get the rig moving again after the engine stalls from fuel starvation (to steep and bumpy for carb) during a technical climb. I am worried about when I get it stuck in the mud or snow, and burning up a clutch.

I like the auto for when I get stuck, keeping it cool really isn't a problem. Or when my wife gets behind the wheel and she gets it into a predicament on a hill (I am less likely to remove the dash board with my finger nails). The nearly infinite gearing due to the torque converter. I am not so fond of possible trail failure or broken cooling line. Or the lost power since it is a hydraulic pump.

I want something that is going to be dependable without fail.

Please, what is everyone else's experience with either trans?

The photos are from one of the last trips I made before the engine tanked.

Tyson

 

[AlaskanWheeler]

I think finding the automatic adapter plate for the cummins will present some issues, the nv4500 adapter will be easier to find since you can use Dodge cummins adapter plates. There is also the Ford option for transmissions depending on what vehicle the motor came from, these are also a lot cheaper then the NV4500. Which are popular to anyone doing a gas/diesel conversion.

 

[Farmboy0007]

I have heard of a large "re-power program" that Cummins did with Frito-lay. Several of their delivery vans went from running a GM 350 v8 to the 4BTA, keeping the original Transmission.

 

[addicted56]

If you are not worried about highway driving just use that SM465 that came with a lot of them. I took mine off that came with my engine and am going the NV4500 route becuase it will be a highway driver. They are a lot cheaper and easier to get and have almost identical low 1st gears.

Also if you want out in the snow that deep I recommend a lift first. Well that and you will not get your engine in there without it. Also 2.7 gears sounds pretty weak sauce. Whats the reasoning behind that?

It is not that hard to get the adapters for the engine. on the 4btswaps website I see them all the time and they can be had for around 600 it seems. I know not that cheap but neither is the 4bt swap

I had a 700r4 from a 6.2L but decided to go the other route becuase I didn't want to have to buy an auto adaptor, I heard adjusting it can be a pain, the stall speed on the stock torque converter was to high, and in the future I plan to put some power behind the thing.

 

[motoloco]

The 4bt is a cool power plant but is too heavy for deep snow wheeling or much off camber wheeling in a rig with that short of a wheel base. I have taken a few diesel rigs on snow runs and had to leave them at the trail head because they sank like a ROCK! Anything under a few feet of snow should be fine.

 

[Farmboy0007]

Well, I am not planning on making it solely a snow rig. I also plan to drive the vehicle on the high way a bit, I don't want to make a trailer queen.

I was thinking about getting the tracks just for winter purposes.

MOTOLOCO To digress, what have you run for tire sizes on your snow runs?

From what I have been able to locate on the 4bt swaps, the engine, fully dressed really won't weigh a massive amount more than the current 350 v8.

I was planning to add a fuel cell somewhere in the rear of the vehicle to counter balance the additional weight.(granted when it is near full)


I have made friends with one the local junk yards, he has a 700r4 that he built up to put in one of his hot rods, but has never gotten around to finishing the project. He is willing to part with it for not much($200). But on the other hand, do I want it just because it is cheaper than the NV4500?

Looking for bomb proof here. . .

I was favoring the 2.7's since I plan to run the Atlas II with super low lows, I figured even with the 2.7's, the trans case in absolute low 10.3:1, and either trans (6.34:1 GMNV4500, 180.8:1 crawl or 3.06:1 700R4, 87.3:1 crawl) I can get a good crawl ratio, and still be able to drive it down the highway at 60mph with out rapping out the engine.

But I am here to gather knowledge from others experience. Please share.

Tyson

 

[Cruisertime]

Depending on how you plan to keep it cool, the auto is a good choice. IMHO. As long as you have a good builder or trust yourself. Getting all the parts needed to make a stout 700R4 is pretty easy. And getting a diesel or low rpm stall converter are avail. .....lowest I have seen is a 700rpm stall 30 spl with furnace brazed fins .....

 

[motoloco]

It was not really a traction issue on the rigs as much as it was sinking to the axle housing and that caused them to anchor right there. One set was 12.50 wide and the other was approx. 11.50 wide. They were super stable in smaller amounts of snow on the road though. It will be way heavier than a SBC not as much heavier than the stock 2F but bill a big difference. I believe a stock 4bt is pushing over 900lbs, just somthing to think about. If you want closer to bullet proof go NV4500.