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Ford 8.8 / 3.07’s


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So, I know the Ford 8.8 is a popular swap from the Explorer’s.  I see the Mustangs had 3.07 ratios.

 

Does anybody see any issues, with wanting to take a Ford 8.8 rear axle from a Ford Explorer & then taking the gears from a 8.8 Mustang with 3.07’s and installing the gears into the Explorer Axle?  Or, can / should I just use the Mustang 8.8 axle?  I haven’t seen any write up on it being done, so I’m guessing it’s a no-go.

 

I’m really wanting to run a 1999 XJ drivetrain (4.0 5spd) in the Comanche, with 30 inch tires.  It’s what I ran on my 2000 XJ with a 4.0 5spd.  I didn’t have any issues, driving around.

 

Thoughts?  Concerns?  Ideas?

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I'm not sure why you'd want 3.07 gears with 30" tires, I think that 3.55 or 3.73 would be better? You could try looking at Randy's  Ring and Pinion for the two applications and see if they take the same gear set, but new Ford Motorsport sets were pretty cheap the last time that I looked. You probably already know that the gears will need to be properly set up whether you buy a new set or a good used one.   I'm not sure of the external differences for the Mustang 8.8 compared to the Explorer but I do know that some if not all Mustangs came with 28 spline axles, while the Explorer has 31.

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Also, depends on terrain. IE hills, mountains or flat land. I do OK with 32's and 4.10's with an Auto in Indiana. In WV, I have issues on many grades. 

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Personally, I prefer 3.55s with stock tires and up to 30s.  They just work better overall.

 

I would advise against used gears.  They're hard to set up correctly.  And most shops won't install them at all.  The ones who do won't warranty the work.  A new set of gears is < 10% of the total cost of a gear install.  May as well go with new gears.

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7 hours ago, ghetdjc320 said:

:iagree:
 

Go with 3.55’s or so for 31’s. Though, on another note, I’m no fan of the Explorer 8.8 for an MJ. 


What’s your opinion on the 8.8, from the Explorer, why aren’t you a fan of it?

 

My ‘88 Comanche is currently 2wd, with a 4spd transmission.  Not sure what axle is in the back.  My ‘99 parts XJ is a 5spd 4.0 4x4.

 

I guess I’m just not seeing / understanding (for my needs) why I should put something like a 3.55 / 3.73 under the truck, with 30 inch tires.  The truck is as aerodynamic as a brick.  It will have less than 200hp.  I don’t tow / hall more than 1500 lbs.  When I do, it’s during hunting/fishing season, so only on the weekends.  I don’t off-road my vehicles.

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I got better fuel economy with 3.55s than the stock 3.07s in my 88 4.0 stick on 30s.  :L:  I'm honestly not sure why Jeep ever put 3.07s in there.  :dunno:

 

but you should figure out what axle you have in the XJ.  if you have the 8.25 I'd just swap that in. :L: 

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I would also not recommend 3.07s for 30s, nor would I recommend an Explorer 8.8. The Explorer 8.8 is narrower than the stock MJ axles. The Explorer Sport Trac pickup has a similar width rear to MJs, but those only had options for 3.73 and 4.10 gears. 

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10 hours ago, 1999 MJ said:


What’s your opinion on the 8.8, from the Explorer, why aren’t you a fan of it?

 

My ‘88 Comanche is currently 2wd, with a 4spd transmission.  Not sure what axle is in the back.  My ‘99 parts XJ is a 5spd 4.0 4x4.

 

I guess I’m just not seeing / understanding (for my needs) why I should put something like a 3.55 / 3.73 under the truck, with 30 inch tires.  The truck is as aerodynamic as a brick.  It will have less than 200hp.  I don’t tow / hall more than 1500 lbs.  When I do, it’s during hunting/fishing season, so only on the weekends.  I don’t off-road my vehicles.

The Explorer 8.8 is just too narrow for an MJ. Even the stock axle width was on the narrow side. Aside from that, it’s a c clip axle, has an excessively large housing and pumpkin shape that tends to shovel into obstacles, relatively small brakes and adds considerable unsprung weight. For 30” or 31” tires you can stick with the D35. You’ll have equivalent pumpkin clearance to an 8.8 on at least true 33’s. 

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