Next Project - Axles

[ParadiseMJ]

My current set-up:

 

88 MJ AW4 D44 rear/D30 front (3.07 gears)

 

I just swapped out my Peugot for an AW4 and the result is it's just OK. I'd like to re-gear/re-axle. I like having the D44 but with the 3.07 gears it's rather gutless. The throttle response is OK, the TV cable is adjusted properly. My XJ has a D35 with 3.55 gears and 265R75X15's (31's). It's pretty peppy but I know it lacks real "torque" or power. The XJ with the D35 has served me well for over 10 years with only regular maintenance both as a DD and a weekend warrior. I can also tow a medium/small trailer without much effort.

 

For a truck that is used only occasionally off road, more on just gravel/dirt road/trails, and in the winter here and there on snowy roads, and most of all on the highway what's my best gear ratio?

3.55?

4.10?

...and so on.

 

I don't need a "fast" truck, but I do want it to pull a small utility or boat trailer up hills without doggin' it half way up. I have an HD tranny cooler installed on it as well.

 

I'd also like to know what kind of modifcation is necessary for an 8.25 or 8.8 (i.e. spring perches, yoke, shaft, etc.). I'd like a disc brake rear axle too, but not absolutely necessary. I will be likely pulling what I need from a yard. I will NOT be re-gearing my present axles. I will not be going SOA either.

[TylerJY]

Why would you NOT want to regear a d44?

The towing package MJ's came with that axle for a reason.

[HOrnbrod]

Tire size?

[ParadiseMJ]

First the expense of re-gearing for me is prohibitive. Since I have NO CLUE :dunno: how to do it, I'd have to pay someone to do it + parts. I think that it could do fine with an axle already geared...even if it's not a 44. My XJ has a towing package as well...but has a 35. I'm on the hunt for a 44 (or something AS strong) with the right gearing...depends on what I find...on the cheap.

 

Secondly, Don, there are 31 x 10.5's on it now, BFG A/T KO's.

[Pete M]

I would do 4.10s: dana 30 front and a ford 8.8 rear with wheel spacers.

[HOrnbrod]

:agree: 4.10 is the ideal ratio for 31s w. the AW4. I ran 3.55s for awhile and the gearing was too tall. The final drive ratio using 4.10s is slightly numerically lower than stock gearing and tires would be (makes the engine turn about 200RPM higher at 65-75 MPH in O/D) but to me that's a good thing. It even helped my gas mileage a bit over stock. D44s with the 4.10 ratio are rare animals, so the Ford 8.8 is a good choice, especially with rear disks. For me though, I'd beat the bushes hard for a D44 and regear.

[Eagle]

For a truck that is used only occasionally off road, more on just gravel/dirt road/trails, and in the winter here and there on snowy roads, and most of all on the highway what's my best gear ratio?

3.55?

4.10?

Of the readily available axles, 4.10 for sure.

 

What I can tell you from my own experience is that 3.73 gears with 31x10.50 tires works out to exactly the same overall final drive ratio (RPMs-to-MPH) as stock tires with stock 3.54 gears. I ran my '88 MJ on 31s with 3.73s for several years. It was great on the road, and passable off-road but not really enough gear. I had actually bought the gears to run in my XJ with 30" tires and I think that would have been a good combination. But the MJ came along, it needed gears, and I had the 3.73s so I threw them in.

 

4.10s will be good for your purpose. They'll be perfect with 30" or 31" tires, and if you don't live on the Interstate at 80 MPH 4.10s are even good with stock tires.

[mountainman]

What is the year/make/model of ford we are after that has the 8.8 in it with 4.10s?

 

I want to start collecting parts to regear and SOA at the same time.

Ill have 31s soon and 3.07s and i don't think it will stay with that combo for long. Sounds like i will prob hate it. lol

[mvusse]

Any year Explorer might have 4.10. It is a fairly common ratio, but not the only ones used, so pull the cover and check the gears. 95 and newer should have disc brakes. Supposedly a flange from a Crown Vic will be for a 1310 series u joint.

 

Be aware the 8.8 is an inch or so narrower than out axles and could cause interference between the tires and inside wall of the wheel well if you run stock wheels without wheel spacers.

[ftpiercecracker1]

Not trying to highjack here, but a local pull apart has about every axle you can imagine and they only want 45 bucks no matter what make, model, year or size. If you could is there any other axle that you would go with other than the ford 8.8? Unfortunately a Comanche is the only thing they don't have so no D44. Obviously the comanche axles would be the easiest to swap out, but what comes next in swapablility besides the 8.8?

 

thanks guys

[mvusse]

Even doing a rear wheel stand while bouncing on 35" tires and a locker I did not manage to damage my 29 spline Chrysler 8.25".

 

Did twist the driveshaft in half, though.

 

Any late 96 or newer Cherokee without ABS should have it. Correct width, pumpkin in the center so you can get correct u joint angle if you do a SYE, correct 1310 series yoke for the driveshaft and you don't have to McGuyver the parking brake cables. 4.0/auto would most likely have 3.55 ratio. 2.5 would have 4.10 no matter what transmission by then, stay away from a 4.0/5 speed as it would be 3.07.

 

Or possibly find a D44 off an early Cherokee. Rare, but not as rare as a Comanche D44.

[ftpiercecracker1]

so a d44 from an early (define early) cherokee is the ideal axle for ease of swap AND durablitily? Will it say d44 on the diff cover? or can it be ID by the number/pattern of bolts on the housing?

[mvusse]

Early as in 87-90, don't know about 84 through 86. More or less stop sign shaped diff cover. 99% of Cherokees that era had a D35, however. Advantages: Axle shafts in a D44 are marginally thicker than 29 spline 8.25, no C clips. Negative: D44 axle tube is smaller than 8.25 axle tube.

 

Which one is the better axle? I'd say the D44. Is there a large enough difference for it to actually matter in the real world? Probably not.

 

29 spline 8.25 is easy to find as there are thousands out there. I have yet to find a D44 under a Cherokee in a junk yard. I did find a metric tonne Comanche once, but the rear axle was already gone. Likely disappeared within hours.

[Eagle]

Obviously the comanche axles would be the easiest to swap out, but what comes next in swapablility besides the 8.8?

Chrysler 8-1/4 from a 97 or newer XJ. If it's from a 4.0L auto you get 3.55 gears, if you find a 4-banger you get 4.10s. Width is perfect, yoke is correct for the MJ driveshaft u-joints. Just relocate the axle perches and bolt it in. It's less work than the Ford 8.8, and very nearly as strong as the D44.

[ParadiseMJ]

Great info guys, thank you. I'm going to the yard on Friday...I will spend most of the time on my knees under Jeeps and Fords just getting the lay of the land...lots of XJ's and best yet, alot of those are 87-90's and lots of Exploders.

 

Why do I get myself into this... :dunno:

 

:wrench: :cheers:

 

...what the hell else would I do? Go fishing?

[ftpiercecracker1]

Chrysler 8-1/4 from a 97 or newer XJ. If it's from a 4.0L auto you get 3.55 gears, if you find a 4-banger you get 4.10s. Width is perfect, yoke is correct for the MJ driveshaft u-joints. Just relocate the axle perches and bolt it in. It's less work than the Ford 8.8, and very nearly as strong as the D44.

 

 

There IS a four banger XJ in the yard, but its a 91. They have a bunch of XJs of all years. At LEAST 25 explorers, even an old J10 :brows: .

 

Will a D44, 8.25, 8.8, etc look the same under all vehicles? Will i be able to distinguish it using the same methods?

[Pete M]

all Explorers will have an 8.8 under them. You're looking for 95+ so you get the disk brakes. check for ratio before buying, don't settle for anything less than a 4.10, and don't pay any more for a v8 model since they are identical inside (only the brackets outside change and you're going to cut them off anyway). oh, and make sure you get the calipers from some explorer (not necessarily the one with the 4.10s) since the core charge on them is huge.

 

 

as for Jeeps,

 

 

and the 8.25 has a pronounced flat section across the bottom of the differential.

 

[ftpiercecracker1]

if i were to go with the 8.8, do the brake lines use the same fittings? or would i need to cut, get the right fitting, and reflange? or adapter? and what about driveshaft length, universals, and E-brake lines??? :???:

[mountainman]

8.25 also has the ribbed cover. That raised portion around the outside of the bolt circle.

A d35 has no such thing. Just flat in that area.

They look much alike under the car. :)

[RynoMJ]

if i were to go with the 8.8, do the brake lines use the same fittings? or would i need to cut, get the right fitting, and reflange? or adapter? and what about driveshaft length, universals, and E-brake lines??? :???:

 

E-brake lines will be different, I know some people have modded their MJ ones to work but when i did my swap I opted for all new cables, the Explorer cables have a little loop on the end that wraps around the ebrake hook, MJs don't have that. The rest of the fittings should be the same if I remember correctly.