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I'm thinking of swapping in a newer trans to my 86 and I'm not quite sure what to swap in

Id like to stay with the automatic i just want something with more meat because sooner or later I'm doing a motor swap from the 2.8 to 4.0

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The trans options for the 4.0 were the manual AX-15, which is the good one, the Puegot BA10-5 which is the bad one, and the AW4 automatic. Either the AX-15 or AW4 will be good choices as both are really good transmissions. None of these trannies will bolt to a 2.8. You should have the Chrysler A904 auto in yours, which isnt a bad trans. Its a smaller version of the TF727 and is readily buildable. It was offered behind Chrysler 6's and small V8's for many years. 

 

One option I'm not sure if you have thought of is swapping in a GM 3.1 or 3.4 V6. This would give you better power and reliabilty without having to go through all the problems of a 4.0 swap into an 86 as it is pretty much bolt in. You could keep the GM fuel injection as well if youre ambitious. There are writeups to make it a stand alone system and easy swap in from a complete donor like a Camaro or Firebird.

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How much power are you expecting and what axles will you be looking at? While Jeep's L6 is a fantastic engine with excellent durability and a flat-as-kansas torque curve if built up correctly, it does have its limits. Personally, I'm running a 4.7 stroker kit from 505 performance in my ZJ, along with blue top injectors, quite a bit of headwork, larger valves, MSD coil and 6AL box, a higher capacity fuel pump, a throttle body "borrowed" from a 5.0 Mustang, 99 intake manifold, a full 2.5" exhaust with a header, electric fans, a high flow intakr and filter, a piggy back ECM from AEM with a wideband O2 sensor and some odds and ends I'm sure I'm forgetting. I love the hell out of this engine and it stomps on a ton of other mills both on and off road, but my buddy's swapped in 5.9 Magnum with some intake, exhaust and valvetrain pieces walks away from it in a standng start.

 

Horses for courses....

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The axles I'm looking into are custom built by my mechanic and from what hes shown me with them they will stand up to King Of Hammers runs

i don't want to roast rubber off my rims or nothing but i want to try my hand at the occasional mud bog 

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id rather step away from v6s and do straight 6 

I'm not digging the v6

I want something that will give me power and goes good with a ground up axle build

 

For an '86 the 3.4L V-6 is a much better choice than the 4.0L. No body work involved, and you can get decent power out of the 3.4L, especially if you keep the EFI.

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id rather step away from v6s and do straight 6 

I'm not digging the v6

I want something that will give me power and goes good with a ground up axle build

 

 

For an '86 the 3.4L V-6 is a much better choice than the 4.0L. No body work involved, and you can get decent power out of the 3.4L, especially if you keep the EFI.

Even better, the GM 3800 Series III ( I think) SC engine should bolt up to any tranny that has the 60 Degree pattern. If you have King of hs Hammers axles, forced induction would be cool as hell!

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If you want auto, the AW4 is great and comes behind the 242ci. If you want manual, AX-15, nv3500/3550. 

 

 

id rather step away from v6s and do straight 6 
I'm not digging the v6
I want something that will give me power and goes good with a ground up axle build

 
For an '86 the 3.4L V-6 is a much better choice than the 4.0L. No body work involved, and you can get decent power out of the 3.4L, especially if you keep the EFI.

Even better, the GM 3800 Series III ( I think) SC engine should bolt up to any tranny that has the 60 Degree pattern. If you have King of hs Hammers axles, forced induction would be cool as hell!

 

I think Eagle was implying more of a bolt-in replacement. As, for years GM has had/recommended their 3.4L V6 as a replacement engine for the 2.8/3.1 in older vehicles. 

I6 is probably the best upgrade as far as inspection and such in an XJ. Otherwise, if you are going through the trouble of a swap, why not a V8? Novak makes everything you could want/need to do the swap.  

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I don't particularly care for V8 engines in Jeeps. Now, before y'all call me crazy, let me explain. I ljve in FAR West Texas and wheel all over the Southwest. For the most part, the terrain around here is desert scrub land and dunes. There are also a TON of rocky areas for you rockhounds out there. What keeps me from giving a V8 any serious consideration in a small body without much space in the engine bay is heat. It's early February and the temp is hovering around 70 degrees. In the summer, 100+ degree days are the norm. Even while night wheeling, it's still around 85 degrees out. I've seen many a L6 powered XJ and V8 powered ZJ puke out their coolant on a summer night wjile going through miles of deep sand and silt.It'z gotten to the point that some guys are running multiple radiators. Myself, I've removed anything extrenous insidd my ZJ's engine bay, have placed washers on the hood's arms to raise the back edge a bit, and have installed louvers along with the prerequisite aluminum radiator and high powered electric fans. I also use a stroked and cammed L6 with a VERY free flowing exhaust. When comparing my ZJ to hr V8 ZJ's and L6 XJ's, I notice that I have a lot more space around and under my enhgine relative to the body than they do. I believe that this helps me stay cool and operational while some of the other guys are having trouble with their cooling. My other gripe with some engine swaps is weight. I believe that a lighter Jeep is a happy Jeep. I skip the huge, steel wheels, fancy sound systems, mega-light bars and ridiculously over built bumpers in favor of a better power-weight ratio, better MPG, and, most importantly, flotation. In fact, my ZJ is 2 wheel drive with a locker. It can go everywhere my 4WD, modded SBC K5 can go, and can do so with aplomb.

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If you want auto, the AW4 is great and comes behind the 242ci. If you want manual, AX-15, nv3500/3550.

 

 

 

id rather step away from v6s and do straight 6

I'm not digging the v6

I want something that will give me power and goes good with a ground up axle build

 

For an '86 the 3.4L V-6 is a much better choice than the 4.0L. No body work involved, and you can get decent power out of the 3.4L, especially if you keep the EFI.

Even better, the GM 3800 Series III ( I think) SC engine should bolt up to any tranny that has the 60 Degree pattern. If you have King of hs Hammers axles, forced induction would be cool as hell!

I think Eagle was implying more of a bolt-in replacement. As, for years GM has had/recommended their 3.4L V6 as a replacement engine for the 2.8/3.1 in older vehicles.

I6 is probably the best upgrade as far as inspection and such in an XJ. Otherwise, if you are going through the trouble of a swap, why not a V8? Novak makes everything you could want/need to do the swap.

I'm sure he was, but it would be around the same amount of work to drop a supercharged 3800 into a MJ/XJ as it would be to go for thr 3.4. They're roughly the same size, you'd still need to do supporting mods, and there's TONS of donors around. Well, around my area, at least.

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I'm sure he was, but it would be around the same amount of work to drop a supercharged 3800 into a MJ/XJ as it would be to go for thr 3.4. They're roughly the same size, you'd still need to do supporting mods, and there's TONS of donors around. Well, around my area, at least.

 

The 3.4 is a lot less work than the 3800. If you take a 3.4 from a V6 Camaro/Firebird, it's a bolt-in replacement because the engine has the same external dimensions as the 2.8, mounts the same way, and shares all the same accessories. It's also already set up for RWD (i.e. longitudinal mounting).

The 3800 is a 90ºV6, not a 60º like the 3.4 and 2.8, so it won't fit the same way. Even a RWD application, which, if I'm not mistaken, doesn't use the same bellhousing bolt pattern as the 2.8, won't just bolt in. The FWD variants have the correct bolt pattern, but they're transverse engines, and as a result the throttle body ends up on the back of the engine, making getting an intake hose on it a PITA. As I understand it, you need to cut the cowl to make room. This is even worse with the s/c version, which pushes the throttle body through the firewall with the tranny in the stock location.

http://comancheclub.com/topic/24546-38l-supercharged/?p=254940 <-- Check this thread out. JeepCoMJ eventually pulled the plug on his 3800 MJ build after a couple years.

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I agree again with the 3.4... Jeepcomj  went through several transmissions too with the 3800 because it was too much power. But if youre set on the 4.0, get a complete running donor so you can just swap it all over and see what the differences are in the radiator core support in order to swap it over as well.

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So, the big difference between fwd and rwd 3.8's is the location of the starter. It swaps sides. While the fwd and rwd blocks are more or less the same, they may not be drilled to have the starter on the "wrong" side. But the bolt pattern will be the 60°V6 pattern, with maybe a slight and insignificant difference due to the relocated starter.

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