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Discussion Starter #1
I just wanted to see what comments I could get out of this. I know of a Jeep Wrangler with a 200 hp 4bt and a built 700r4. He has been running this for 2 years now with no problems. I am currently doing my conversion on my jeep and was wanting to do the same. After reading on here a bit, a lot of guys are not having good luck with the 700r4. Is it because of the weight of the vehicles?
 

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I would say prob not. A built 4L80 might. For the money you would spend on a built 700R, go with a 47RH or a diesel based trany.
 

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Discussion Starter #8
Not enough room to use any other trans. Basically I have 3 options without moving the rear axle back. TH400, 700r4, or the 4l60.
 

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Talking with the guys at Monster Transmission and performance...They have built 4 of these 700r4 trans for use in a Jeep and all have worked well. I explained the torque these engines produce they agreed that it is a lot, but because of the weight and the fact that I will not be drag racing this Jeep and I will not be putting 75% throttle in 3rd gear that it will hold up.

Does anyone know what breaks in them or what goes wrong as to why they will not hold up?
 

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Everything is physically to small to properly handle the torque of a hopped up diesel. Also, the lube/cooling circuit is not designed to cool the trany off at high torque loads and low rpm.
 

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One of the guys on here was saying the case can break just forward of where the T-case bolts on, but that was in a rock crawling application IIRC.

Other than that, low fluid flow at low engine speeds like KK said, as well as not setting the TV cable up right (700R4), with electronic control that isn't an issue though.

Which dimension is impractical on the 4L80E?

From what you've said I expect it's length, but I don't want to assume.
 

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Discussion Starter #12
Yes...with the adapter from Novak Adapters...its about 6" longer than the 700r4. I am not sure if anyone has ever talked with Ken at Novak adapters, but he sounds very knowledgeable. He explained that its dumb to put a diesel in a Jeep, but that people want different things. He believes that the 700r4 will work in Jeeps because of how light weight they are and that 1st gear is very strong and will probably be the only time more than 50% throttle will be used. After the vehicle is moving only 30% will be applied at the torque level or the 4bt. I Know that I will have to make some WOT runs with it though. I just keep thinking back to the Jeep that I know is working with the 700r4 and has been for over 20,000 miles.
 

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I've read about a few light vehicles where the 700R4 survives behind a 4BT, but as I mentioned earlier they had lower output variants, and were left stock.

If you want 300 Hp from a 4BT, that can be done, but I wouldn't expect a 700R4 to survive behind it.

If you want to get it going, you will likely want to leave the engine stock, at least try it that way.

It's too bad the 4L80E winds up too long.

I'm kind of surprised there isn't some other combination of adapter and transfer case that would work.
 

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I'm kind of surprised there isn't some other combination of adapter and transfer case that would work.
47RH, it's prob longer then the 700R4, and the stock jeep t-case bolts right up to them.
 

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700's have several weak points, but by far and away their biggest is a simple lack of clutch surface area and hydraulic pressure at low RPMs. Few gas engines, and none of the ones ever used in front of a 700, make their peak torque in the 1500-1700 RPM range. A 300HP Cummins is going to make at least 600lb-ft in that RPM range. Even a 200HP 4BT is over 400lb-ft (the ISB170 is rated at 420lb-ft). The rated max input torque for a 4L65E is 380lb-ft, and the 4L65E has upgraded internals over a regular 700 (although said internals can be retrofitted to a 700). The only reason they live behind 6.0 gas engines (which make 380lb-ft at 3000k or so RPMs) is because the peak torque RPM is higher and the computer can pull timing to reduce the torque during shifts.

If trans length is the issue, perhaps using a different trans AND t-case combo is in order? I am helping a friend with his Jeep YJ 6.0 swap right now, and we are using a 4L80E/NP241 combo with a JB conversions super short slip yoke eliminator in the transfer case. In the end, the combo is allowing him to use the same rear driveshaft he used before the swap - previous combo was a 4.3, 4L60E, NP241 with a slip yoke eliminator (not the super short SYE, but the regular one).
 

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Discussion Starter #16
The 47rh is def too long. The 4L80 is looking like an option, but the 700 is still what I would prefer. I am going to call a few other trans builders and see what they say as another option.
 

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Try Performabuilt. I have a Level III Invincible that I will most likely be running behind a 4bt. Its good for 800rwhp according to them. That should be 600 or so ftlbs..
 

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I'm running a "stock" 700r4 behiind a 4bt w minor mods with great success. I have about 10k on the swap and really dont treat it nice. I was warned against using it but did it anyway because I had it, it fit nice and was easy. I spoke w monster trans before doing it and they claim they can build them to hold up so I figured Id go that way when I smoked this one. I did add some weight to the govenor, used a diesal converter and a shift kit to clean up the yo-yo effect but nothing in the hard parts. I think the the big deal is this 300hp number. And my question is why 300hp. I say build it w a stock 4bt use the 700 and see what you got. I think you will be very surprised and impressed with the motor. The power is awsome especially in a light vehicle. Then fix or mod what you tear up. IMO once you get it engine in you wont want a bunch more power. If your converting from a 4.slow it will be night and day.
 

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Wittboys, I see you have the PODs in now, how much of a difference do you believe they make?

Do they help off the line?
I'm not shure I actually started with them in the build. A turn on the fuel screw made a big difference and it will smoke now. I like them. The 700 shines down low all the way through 2nd. The 2-3 and 3-4 shifts are a little late. I think a little more gov spring will let it pull through. It will break loose the rear on the 1-2 shift if you stay in it. It will do a burnout all the way through 2nd so I guess what im saying is I dont have a problem off the line its at the end of 2 and 3 that I cant perfect.
 
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