[95YJ]

I'm looking into converting to a 4BT, but am having some trouble deciding if it would be a good idea. What I'm looking at is putting a four link suspension in with it and stepping up to even larger tires. I currently have 36's and was thinking about going up to 40's when I do the suspension (not certain about that yet). I'm not looking at driving this vehicle all of the time, but will need to be able to get to highway speeds. Considering there isn't any place places to take it off road in the area I'm in. The first question (of many probably) is what would be the ideal manual transmision for such a set up? Considering the additional weight what would be the best struts and springs for a moderatly soft suspension?

Any input would be appreciated, considering this will be the biggest modification I will have done. If I say anything out right dumb just let me know

 

[CrewCab59]

The Cummins fit nice into a jeep, I say do it you have the time and cash and know how to fab .The nv4500 is the way to go with and also having a choice of t-case adapters as well.The tires going to 40's ,a 4 link is the only way on a short WB. Do you have any plans to lengthen the WB ? That would help a lot .

Thanks
CrewCab59

 

[95YJ]

Well when I did the four link I was going to put a ford 9", maybe depends on what I can get for a decent price. I'll be moving up on the size of the axle though. I was also going to be moving the axles forward and back, respectivly, for more stability. I just haven't gotten very far into the decision making process.

 

[95YJ]

Doubler?

Well I've been doing some reading. The question I have is that if a doubler would be all that advatagous? Considering the torque that the 4bt would create anyway? I should think so, but if so that is something that would be modified later on down the road. The set-up I've pretty much decided on is 4bt, nv4500, np205 transfer case. Haven't made any conclusive decisions on what kind of axles I would rather use at the moment. I suppose it will depend on what I can find in abundance in the 1/2-3/4 ton range. I just need something easy to find so as to bring the price down some. This mod will probably cost quite a bit as it is. I am still set on the 4 link, but still not sure if I want to move up to 40's (may be a bit much).

 

[boots4]

The motivation to run a doubler usually stems from the type of wheeling you do. While I really didn't need a doubler for what I do (especially with the 4bt's torque curve), it worked out being almost the same price for me as buying an adpater for my tranny to transfer case or putting in a 203 doubler and adapting it to both my tranny and transfer case. So I'm choosing to run a doubler and having the best of both worlds; highway driving and slow speed crawling. Since my rig is still in the building stage I cannot comment on how it actually performs but at least I'll have the option.

 

[averagef250]

For a short wheelbase you can run a HP60 housing in the rear to help with U-joint angles. Any axles you decide on will need modified anyway, might as well start with something cool.

As for transmission/t-case/ front axle- The NV4500 is a tough tranny and well built, but has serious 5th gear issues behind a diesel unless you run a full spline torque king shaft in one. Even behind a stock 4BT or any diesel for that matter you will eventually have a failed 5th gear. Vibrations, not power are the reason for the failure. More power obviously accelerates the failure though.

I think the most bang for the buck is a ZF 5 speed. The 88-97 Ford S5-42 diesel version is close ratio, very tough and bolts directly to an NP205 t-case. You can buy a ZF 5 speed for 1/3 to 1/2 the cost of an NV4500 any day, you don't have any need for t-case adapters or a special mainshaft you just need to buy the cummins to ford adapter plate aftermarket. Unless you got very, very lucky that $800 adapter plate still costs far less than the NV4500 and all the stuff to make it work.

A 66-77 Ford HP44 front is a nice setup with disc brakes. Early bronco 44's don't need cut down but are low pinion which doesn't work so hot for tons of lift and a short wheelbase.

 

[95YJ]

Tranny issues

Well a lot of good input. This is exactly why I'm looking for advice, and ideas. Just want to make all of the decisions before I go and start ordering parts. Considering the amount of work it's going to take I want to know eaxctly what's going on it before I start. The more time I spend with the Jeep running the better.........

 

[tacoma]

I'd go with a 241 transfrer case for the lower 4lo, personally.

 

[DarylB]

If you're gonna play on the rocks and dont want a doubler (length issues) you could get the LoMax 3:1 gears for your 205 or a whole LoMax Case.

http://www.jbconversions.com/pages/products/lomax205/completetcase.html

 

[tndonor]

Wheel base will bite you in a wrangler. Not saying it cant be done because I have seen it done. Its what approach you take to it.

-run a manual instead f an auto
-stretch wheel base
-get a multi speed case like Atlas or Stak
-Get a 3 to 1 kit fo rthe 205 or 4.1 for dana 300

You can get and build a D60 or 14 bolt rear cheap. No need in snapping shafts. If you plan on building that big, go ahead and ge the driveline ready so you are not doing another build..... if time and money allow of course.

Most of all have fun with it!

 

[95YJ]

Well I had already planed on streching the wheel base, but I'm just not too sure how much I'll be able to get away with. I've been doing some reading about the Ford S5-42 that was recomended before for the transmition. If it is that much cheaper to get, at least that much easier to find. I'll probably be going with it instead. I'm going to start pricing stuff soon. Maybe next weekend, hit the junk yards. I know It's going to be expensive, just need a guess at the total amount I'll be looking at.

 

[toyota231]

If i were buiding that rig i would probably stay in the 36-38" tire range for a DD. Run a HP44 front and 9" rear. Both are easy to build and cheap to start with. One tons fronts just cost so much anymore (in the $800 to $1600 range). Rear 60's are pretty cheap and easy to build, depending on where you get the axle to start with (junkyards in NC love their axles). Thats just a suggestion and hopefully it will help.

Also where are you located at in NC? Just wandering cause im starting a build for a buddy of mine in a couple weeks and it could be helpful to you even though it is a toyota. We are putting a 4bt in an 87 toyota w/ rockwells and 52's. I also know someone that can get cummins parts pretty cheap.

 

[Ggg]

From what I read on the LoMax site the 205 t-cases and the kits are only for the GM 205. So they are only passenger drop, Ford,YJ,TJ, etc are all drivers side drop.

 

[95YJ]

If i were buiding that rig i would probably stay in the 36-38" tire range for a DD. Run a HP44 front and 9" rear. Both are easy to build and cheap to start with. One tons fronts just cost so much anymore (in the $800 to $1600 range). Rear 60's are pretty cheap and easy to build, depending on where you get the axle to start with (junkyards in NC love their axles). Thats just a suggestion and hopefully it will help.

Also where are you located at in NC? Just wandering cause im starting a build for a buddy of mine in a couple weeks and it could be helpful to you even though it is a toyota. We are putting a 4bt in an 87 toyota w/ rockwells and 52's. I also know someone that can get cummins parts pretty cheap.

From what I read on the LoMax site the 205 t-cases and the kits are only for the GM 205. So they are only passenger drop, Ford,CJ,YJ,TJ, etc are all drivers side drop.

Ok been gone for awhile, not by choice really, work go figure. I'm over in Havelock. I've been thinking about it more and more, and I just need to trash that wore out crap in my jeep. So I'll be in the market for the 4bt in about 6-7 months, going away again already. I'll keep the t-cases in mind when I look at them. Where is the build on the 'yoda going. I'm sure your a ways into it, but I'd like to have a look see if it's close. If I can sink enough money into it fast enough when I get back I have plans to go out on a 2 week trip with a guy I know and a buddy of his. See about getting someone to watch my kids, drag the wife, but I don't think it would take much to get her to go. She's been wanting me to get her a jeep too. If anything she'll just probably get more pushy about getting her one.

 

[whitefeather010]

Did your YJ ever get the 4bt? I have 95 YJ and want to do the same swap. Wondering if you have any tips.