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Wondering what gears tuffin up my 86 MJ.


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I am starting to gather parts for my MJ's new overhaul this spring. I am wondering what would be some great gears for the front and rear.

I am keeping the 2.8L and adding fuel injectors for a little help. I'll be updating the whole power steering system as well along with several other things to get my baby purring great.

 

Thanks in advance for the help.

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what gear ratio do you have now? Which rear axle? What size tires are you looking to run?

 

not sure what your plan is on the FI, but grabbing an early 90s Camaro with the 3.4 and wiring in the injection makes for a good combo.

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The truck is straight stock from 86. I have no modifications done to it as of yet. So I am not real sure on the gears in it. I do know that right now it is gutless as far as power. It will crawl anywhere but HP.

I had thought about the 3.4 exchange, but said no to it. I was told that a change in gears and the fuel injectors would give me all I'll need.

 

As far as tires I hadn't thought about that either. The Jeep will be my weekend rock crawler, but it will also act in my small snow plow fleet during bad weather. So I am trying to find the happy medium. As far as wheels stand 15 inch. I forgot what Chrysler puts on the rubicons, but I have had good luck with them on moderate trails. Haven't taken the rubicon on some heavy trails yet though.

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gotta figure out what gear ratio you have now before thinking of upgrading.

 

What injection system are you contemplating?

 

swapping gears in an axle can cost up to 600 per axle. is that in the budget?

 

What size tires are you going with?

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gotta figure out what gear ratio you have now before thinking of upgrading.

 

What injection system are you contemplating?

 

swapping gears in an axle can cost up to 600 per axle. is that in the budget?

 

What size tires are you going with?

 

Pete neglected to mention this is for labor. Parts can add a few hundred more.

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If you tell us what trans you have we can probably guess what gears you have. If its a 5 speed you probably already have 4:10, but I'm not sure what gearing they put behind the V6 auto in MJ's. I have an 86 wagoneer parts truck with the v6 and A904 auto, and I have yet to confirm what gears it has, but in some research, Ive found it could be either 4:10 or 3:73.... the 3:73 being very rare early on. I'm hoping for the 4:10's. My 87 got the 4:10 set of axles out of my 86 MJ and will soon get its 5 speed trans also. And I'm hoping to use all the guts from the 86 waggy to re do the 86 MJ as it has the auto and the full time transfer case, though it is the less desireable one... NP 228. A 3.4 swap would be perfect in that. Maybe someday.

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I don't really have a budget. It is a 1 year project that has lasted 10 years. I just got to the point where I can go back to playing with it again. It is a bit gutless and I was told that changing out the gears and adding a fule injection system would cure some of the gutlessness, versus swapping the engine. I am not real worried about budget since I'll just keep throwing money at it for as long as I own it anyways. May as well be all now than all over time. I am going to use it as a semi daily driver, plus toy. I am going to use it as part of my snow fleet during these times of year also.

I really wish I new more about it as far as type of tranny and such I just don't. For having this truck for so long I am still quite a newby to the whole thing.

I only assume that it is stock, as much as that tells. I do know that the guy I bought it from rebuild the engine.

 

I plan on getting a FI system from a camaro of the same engine, but I did find some brand new ones online for not a bad price. Hell I may just go for a brand new crate and add the rest it may be more cost effective in the long run. I really don't know.

Mostly what I am looking for here is possiblities for thought. I will be starting the project over the summer.

 

Thanks for all the help that was already given and that will be given.

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the 3.4 has more advantages than just a bigger displacement. it's a superior block to the 2.8, with a better oiling design. :thumbsup: far less likely to blow a rod out the side. :yes:

 

finding a cheap used maybe wrecked Camaro and using the 3.4 and its fuel injection system can make a huge difference in your truck. But others will argue that you could also buy a wrecked XJ and do a complete swap to the 4.0L. choice is yours. but I would not put any time/effort into the 2.8L block. It's like the Dana 35 and the peugeot transmission. it's just not worth it. :(

 

If you have an auto trans, then you have a 904 trans. If you have a 5spd manual then it's a AX-5, if 4spd, then an AX-4.

 

You need to find out what gears you have now.

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