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Best Rear End Swap Out For A Stock Dana 35 And Gears


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Hello again fellas,

 

Let me start by saying I am not a mechanic so i will be paying someone to do all of the work.

 

When i bought the truck (1988 MJ) it was already lifted with 33 x 12.50. Originally it was going to just be a truck to run to the dump with and throw a canoe on from time to time. But now after playing in the mud and hitting up the Potts mountain Jeep trail i am finding myself dying to make this truck a serious toy.

 

My buddy has told me that the Dana 35 rear end in this truck is junk and that its likely after a few more passes through the "mud pit" i will likely be replacing it. After reading around in here it seems that replacing the 35 is plain out dumb. So my question is which rear end should i be looking to buy. I have seen people doing ford 8.8, dana 44, but i have no clue which is the easiest swap for an 1988 MJ or the toughest.

 

I also hate the gear ratio that's in the truck now. It may as well not have 5th gear, i never use it. can anyone recommend a good all around gear ratio.

 

Sorry if i sound like an idiot, I just fell in love with my truck and now it sucks more money out of my wallet than my wife and kid... :)

 

I would love to get some pictures of the truck on here but it says my file is to big to upload.... :(

 

Thanks again guys as you are alwasy very helpful with any and all questions.

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If you can find a Dana 44 from another Comanche (with the correct gears to make it easy, assuming yours is 4WD), then that is your best bet. You can still find a D44 with non-matching gears if you can't get one with the correct gears, but you'll have to bring it to a shop to swap gears, which usually isn't cheap. On the flip side, a F8.8 isn't cheap either, but for different reasons. You'd have to weld on new leaf spring perches and get a yoke adapter to mate it with your driveshaft. But, a F8.8 can be found from a '96 or newer Explorer with disc brakes and trac-lok if you are so lucky. Sometimes even with 4.10 gearing.

 

Other options, you can try finding a D44 from an XJ/Wagoneer (rare, also) but again, leaf spring perches need to be welded bottom side if you're keeping the stock, spring under axle (SUA) configuration.

 

My suggestion... find yourself a Chrysler 8.25 axle from a '97-01 XJ (those are 29 spline shafts) and have a shop cut off the SOA leaf perches and weld on some SUA ones. These axles have a strength near D44 (not as beefy as an 8.8) but can be had for reasonable prices and they are a dime-a-dozen. I believe some '91-92 MJ's used these axles also (the 27 spline version) and those would be a direct bolt in. Keep in mind though that if you go the C8.25 route (either from a XJ or MJ), you will need larger U-bolts (3 inch diameter) and the MJ plates/shock mounts to make the swap.

 

One last thing about the C8.25 option... if you wish to have disc-brakes later on, you can get rear discs components for a KJ/Liberty and those are direct bolt on with no modification.

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You can also use a AMC 20 rear from a '86 Comanche. Their strong and had.10 gears and are direct bolt in.

 

Looks like this..

 

For some reason, the posting won't show I typed.10 in the line above. Must be a glitch. Tried editing 3 times.

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How are the Dana 30 front ends on these trucks???? are they pretty tough or should i be looking to upgrade the front end too since i will probably have to buy gears for it anyway.

The high pinion D30's are surprisingly strong. You can fix a few weaknesses fairly inexpesively by upgrading the joints and going with a solid shaft in place of the vacuum disco setup. It becomes a fine line if you have to regear, add lockers, weld tubes, truss, one piece axles etc... most would agree that it is not worth that kind on money so you have to have an end goal in sight to make your own decision. For most of what we use these trucks for, the D30 works nicely if you don't get too crazy with them.

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I don't plan on doing a lot of rock climbing or anything like that. We have a couple steep power lines we ride up and a couple nice underground springs that provide really nice mudding. I think the D30 will most likely be fine.

 

thanks to all you guys with the great knowledge!!!!!

 

Finally got a half butt pic up....

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look around in you pull it Junk yards, normally the price is cheaper than a they pull it.I bought a XJ D44 from a u pull it for $90... (actually all the truck axles where about $90 dollars total no matter what it came from)...

 

now getting the darn thing from the back of the yard in a wheelbarrow with a nearly flat tire to my truck that's another story i don't want to remember..

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look around in you pull it Junk yards, normally the price is cheaper than a they pull it.I bought a XJ D44 from a u pull it for $90... (actually all the truck axles where about $90 dollars total no matter what it came from)...

 

now getting the darn thing from the back of the yard in a wheelbarrow with a nearly flat tire to my truck that's another story i don't want to remember..

 

I feel your pain on that one... except mine was a D30 and C8.25 with 4.10's for an XJ pushing the wheelbarrow up hill... Yea, that freaking sucked.

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I have put gears and a locker in a 35 and would never do it again! I have an 8.8 with 4.55 gears ready to go in soon. If you have a manual transmission and want to do the rear end on the cheap I would get an 8.8 out of a 2 door Explorer as to get the 4.10 gears, although the more common 3.73 gears will be useable with a 5 speed and 33's. If you get a 91-94 rear end with drumb brakes there is less work involved with the swap (cheaper since you'll be paying to have it done) and the 8.8 drumb brakes are an improvement over what Jeep used, and the park brake is better than in the disc rears. Most of these diffs have a posi, and Ford motorsport sells new friction plates for the posi. If you did this you will end up with lower gears and a limited slip all for the price of the rear end. Now all you have to do is get matching front gears and a carrier. I think it will be cheaper and stronger than the 8.25 as most of those have 3.55 gears that you will want to replace to be used with 33" tires. But look around, you have time and you might find a 4.10 geared 8.25 out of a 4 cylinder Cherokee.

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well guys thanks a bunch for all of your help. I drove the truck to work today and noticed some oil drops under it when i went to lunch. It appears my rear main seal has just started leaking. So there goes my rear end money. The comanche emblem should be the $ sign...... :doh:

 

Does anyone know if the tranny has to be dropped on the 4.0 or if you can get to from removing the oil pan. So i don't look like a complete idiot when i take it to the mechanic.

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i just had the valve cover gaskets replaced, along with all the fuel injectors, fuel pump, fuel modulator, starter, flywheel, clutch, slave cylinder, and track bar... LOL My wife would kill me if she knew how much money i have in this truck.... no to mention the new MT 33's . :MJ 1: .

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