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Tjeep 10-06-2010 04:05 PM

tj 37's engine swap?
Hey guys. On my last post someone said you need an engine swap for 37's. In the while I've been reasearching jeeps on 37's I've never seen anything about an engine swap. I have the 4.0 6 cyl. I was going to get the egde trail jammer kit for it. So if I want to put 37's under it on 6 inch lift stretched 5 inches do I need a swap? Also what axels front and rear? Locked front and rear.

AzTJ 10-06-2010 04:07 PM

You don't need an engine swap... axles and gear. I'd be running at least 5.13's. The 4.0l is a strong enough motor is you got the gears. Most people swap to a V8 or something for more power for more wheel speed in the mud and what not.

Ibuildembig 10-06-2010 04:16 PM

I wouldn't run that deep of a gear with that short of a tire

Tjeep 10-06-2010 04:19 PM


Ibuildembig 10-06-2010 04:22 PM

I was thinking more like that or 4.56. The lower the gear the weaker the gear...good thing to remember :)

snwchris 10-06-2010 05:59 PM

The 4.0 is fine, no swap needed for 37s

Is your jeep auto or manual... that will help determine gearing.
I would say atleast 4.88 if manual and 5.13s if auto.

There gearing calculators all over the internet if you do a quick search.

I thought in the last post you already knew your axle route.... since there's 3pgs of info already given.


Ibuildembig 10-06-2010 06:03 PM

Or another thought....just leave the gears alone and buy an atlas or a stax then you have the best of both....cruising speed and crawling speed

Tjeep 10-06-2010 06:08 PM

Ima a trail rider so no crwlein for me. There were so many different opinions on my other post I got confused if they were talkin about axles for 37's or for 38's.

snwchris 10-06-2010 07:50 PM

OK, either Rubi D44's with alloys will work with 37's, especially if you get the RCV Front axle shafts. Another option are Ford 9" w/ big bearings and 31/33 spline shafts. For the rear I've seen alot of people run the Ford 8.8 with great success. It's stgronger then the Rubi D44 and there's plenty of aftermarket for them. If you get the 8.8 make sure it has atleast 31spline shafts. If you look on pirate4x4 there a few Currie 9's forsale and a couple 8.8's as well. Some already have the TJ brackets or you can buy them and have welded on.

Another option would be D44s from an older Waggy (wagoneer) or look at some of the older Ford HP D44's as well. I believe there was a guy on pirate selling a built 44, but not sure what price was.

You could also try the new JK D44s, thery are stonger the the 03-06 Rubi 44's and tons of aftermarket for them as well. I believe they measure out as 65" wide maybe just tad wider.


Tjeep 10-06-2010 08:08 PM

So how much does the 8.8 cost? So 8.8 rear and chromo 44 or should I go to rubi ones? I really liked the chromos and have seen many people run them

snwchris 10-06-2010 08:30 PM

The 03-06 rubi 44's will This is what I'm currently working on to start gathering parts for this winter. Mine will be trail only and very limited street cruising. I still keep my eyes out for some D60's as well. Just 2 wks ago there was a front & rear going for a great price too. On the rubicon owners forum there's quit a few running the 44's and 37s as well.

The JK 44's have been run by numerous JK owners on the JKforum running 37's with no issues. You'll still have to regear. As for price on the 8.8 they can range depends on if already rebuilt or you need to build or if one from an aftermarket place.

Check out East Cost Gear Supply, they sell ready to go 8.8 in variuos prices depending on what options you want. If this is truely a trail vehicle only and will not see any road time, then another option is running Detroit lockers or full Spool to keep the price down.

snwchris 10-06-2010 08:57 PM

Here's a few examples, also more then liekly you'll need a Drivers Drop axle, depending on what year your Jeep is.

D44 built 44/9", 38.5 TSLs/ wheels. misc jeep junk - Pirate4x4.Com Bulletin Board

Ford 8.8 Ford Explorer 8.8, 3.55's, Northeast PA, $300 - Pirate4x4.Com Bulletin Board

Built 44's is there still a market for built dana 44's? this is what i got. - Pirate4x4.Com Bulletin Board

Tjeep 10-06-2010 09:25 PM

How much should a V8 cost? Is it really worth it? How much would it cost to get it installed for me? I have a 2000 tj sahara

Tjeep 10-06-2010 09:47 PM

Alright I'm kinda saying the same things as my last post but I never got an answer. So 6' lift 37's and 5' wb stretch. Hey where would I find the PA lift law stuff?

snwchris 10-06-2010 10:02 PM

I feel like this is getting very repeatative.... have you not read what has been posted here and on your last 3pg thread. Advice is being given, but it seems like your not understanding.

You DO NOT need a V8, the 4.0 has more then enough.

As for lift, a 4" Lift with either TnT Hy-Lines, Trent fab high fender or Gen-right will clear 37's. NO need for 6" of lift. Low COG is what you should be aiming for.

I think on I thought there was a section of lift laws by state, but not 100% sure. You should be able to do a google search or contact your DMV.

snwchris 10-06-2010 10:19 PM

Based on how much you need installed and fabbed for you... your biggest expense is going to be shop labor rates, especially if your asking how much for someone to install for you. Again in depends on the rates in your area, here in NE OH labor rates are cheaper $60-$75, where as in Chicago where I previously lived they were $90-$100.

AzTJ 10-06-2010 10:27 PM


Originally Posted by Ibuildembig (Post 805388)
I wouldn't run that deep of a gear with that short of a tire

That's why I said axles & gears. :D

burton160w 10-06-2010 11:54 PM

Wasn't this all covered before in your other thread?

I was the one who said I'd recommend an engine swap. Do you need one? No, but if it was me, before investing that much in tires, I'd be looking to swap my engine first.

You really need to take some time and hang around the forums a while and read up. This stuff gets covered all the time and reading and researching is really the best way to learn. Slow your roll and plan everything out.

Tjeep 10-07-2010 05:51 PM

It was covered in my previous thread but i was not sure if they were talking about 37's or 38's. And also i didn't understand a lot of what the people were saying like trussing up an axle or ring and pinion and stuff like that. So i made a new thread to 37's and made sure i ask about axles for it. On the other post people for saying 14 bolt now there saying 8.8 so there is a difference.

Ibuildembig 10-07-2010 05:53 PM

I wouldn't use a 14 bolt in anything...too heavy, hang too low, and notorious for eating wheel seals.

Tjeep 10-07-2010 05:57 PM

im new to jeeps so i just want to approach every angle so i jack it up right the first time. someone say i need something i ask a question. then someone says i dont need it i look into it. So i looked into the v8. I know its repetative but when one person says you need this then i ask what would it do. Then someone says i dont need it. I ask a question about it and reasearch it. so that might be repeating a lot but it makes sure that i will get a good rig.

Jerry Bransford 10-07-2010 05:58 PM


Originally Posted by Ibuildembig (Post 805388)
I wouldn't run that deep of a gear with that short of a tire

For 37" tires and 5-speed transmssion, 5.13 is the right ratio, if not 5.38. I ran (and still run) 4.88 with my 35" tires when I had my 5-speed tranny and I would not have wanted 4.56. With my replacement TJ running 35" tires, 4-speed automatic, and 4.88 gearing, it needs a lower gear as it lugs on the highway in overdrive... the engine rpms are way too low. If I had the $$$, I'd regear to 5.38.

And no, Tjeep, a bigger engine is not needed... the 4.0L is capable of running bigger tires than that with the right axles geared appropriately. With the right gearing, the 4.0L has more low-end torque than some V8 engines.

You need a minimum of a Dana 44 in the rear and replacing the front Dana 30 with something stronger is highly recommended. The D30's ball joints, inner/outer C's, brakes, axle tubes, u-joints, etc. are not up to running 35" tires, long-term at least. And replacing the D30 with a Rubicon front D44 wouldn't help since it uses all Dana 30 components except for the pumpkin, R&P gears, and inner axle shaft.

Tjeep 10-07-2010 06:18 PM

Please you guys help me with this first of pumpkin what is that and R&p gear.

And can i get a cb with a snorkel? Well the real question is where does the cb hang? im not going past more than a inch or two above the engine. If anybody know rausch creek i want to do lake christy so bad!

Jerry Bransford 10-07-2010 06:32 PM

The pumpkin is the big pumpkin shaped thing in the center of the axle... what the gears and differential are inside of. The R&P is the ring I pinion gears that are inside the pumpkin. They are the main gears that connect the driveshaft to the rear axles.

What's a CB with a snorkel? You can buy a CB (radio) and you can buy a snorkel but the two aren't normally said in the same breath. And by itself, a snorkel is not enough to keep water out of all parts of your Jeep where it shouldn't be. What year TJ do you have and what transmission?

Tjeep 10-07-2010 06:47 PM

2000tj manual i know im gonna get the guy puttin the stuff on for me to seal it up. Cb radio With snorkel

Jerry Bransford 10-07-2010 06:55 PM

Can I recommend you not plan on taking your TJ into water so deep that it will go an "inch or two" past your engine? You have no idea what doing that can do to the sensors and evaporative system, not to mention the tops of your remote vent hoses will have to be extended upwards and the foam in your seats will take weeks to dry out. And water in some of the electronics that are pretty much impossible to seal will cause other long-term headaches.

In other words, that kind of deep immersion is not something I'd willingly do to a vehicle as new as a TJ that depends too much on sensors and electronics to run properly. The usual max depth recommendation is no higher than the bottom of the headlights.

snwchris 10-07-2010 07:09 PM

Jerry's right about the 03-06 Rubi 44s using D30 outers. It can still work but it does require at times more maintenance. I know a few people running this set-up now on 37's and have no major issues with it. They have noted though that they sometimes have to do Hub Assemblies and Ball Joints about every 2yrs. It also depends on how hard you wheel it. Budget is another factor as well and sometimes you can find built rubi axles as a set thats a little more friendlier on the wallet.

Since obviously you'll be paying for labor, that's going to be cutting into your budget big time.

So here's my next big question... after this person does all the work and installation for you, if you break on the trail far from the parking lot.... how are you going to know how to fix or do a trail repair?? Just food for thought, cause 2yrs ago was out with a few people and had someone tag along who had bought a built Jeep and knew nothing of it. It broke on the trail and he was freaking out since he had a mechanic do all the work and wasn't sure how to fix it or how he was getting home. My friends and I helped fix it up to get back on the road. After that he started hanging around with us and the club and learned to be a better wheeler and how to fix things since we would do wrenching parties or build parties. Nothing better then learning how to work on your own rig with a group of friends and people that can show you the tips & tricks. Remeber we were all newbies at one point or another. Heck I still learn things

Your new to Jeeps its understandable and no problem on the questions, it just felt like everyone was going around the same bush. If you already haven;t you should get out and wheel your jeep stock, keaner about its capabilites cause a stocker will still impress you. Also it's a good way to develop your wheeling skill as well.

Jerry Bransford 10-07-2010 07:13 PM

Yep, X2 and right-on with snwchris's remarks on getting to know your Jeep & its mods well enough to be able to attend to your own problems on the trail. No one minds helping another Jeeper when he's broken down and in need of help but NO ONE likes to have to do all of the work and crawl under the Jeep to get him rolling again. Especially while its owner stands to the side drinking a beer and not doing much else besides wringing his hands or BS'ing about the cool obstacle that busted his Jeep.

Ggg 10-07-2010 07:25 PM

I would say tire to axle size limits are the same for a D35 as for the Rubi 44. They have the same weak points thus the same strength overall. I think the Rubi D44 is a misnomer, it should be called a D35 hd.

Jerry Bransford 10-07-2010 07:29 PM


Originally Posted by Ggg (Post 807591)
I would say tire to axle size limits are the same for a D30 as for the Rubi 44. They have the same weak points thus the same strength overall. I think the Rubi D44 is a misnomer, it should be called a D30 hd.

Corrected. :)

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