I have a 93 flareside lifted 3 inches with 33" tires. I want a limited slip differential. I have the 8.8" rear end. Can I get the gears out of a Ford Explorer with an 8.8" and the differential? What gears should I get ?

 

You want 4.10 gears minimum and yes those from an Explorer 8.8 would work.

 

Gearing depends on what you are looking for and what engine you have (maybe transmission too, but that won't have as much impact).

If you have a 302 I'd agree with conanski. My '71 Bronco (302, 5 spd OD manual trans, 33" tires, 4.10 gears) is fine for almost everything. It could pull 3.55 gears empty, and might be a little better on the highway like that. But when towing my boat (~7000 lbs total weight, Bronco and boat) it's a dog. 4.10s are a good compromise, 4.56 would be better if I did much towing / hauling.

If you have a 351 personally I'd go with 3.55 gears. I had that in my '95 F-150 (351W, E4OD, 33" tires, 3.55 gears). It was just what I wanted empty. And several times I carried my camper and towed a Jeep (10,000 ~ 11,000 bs total truck and load), including one trip through the Colorado Rockies. It slowed down up the steep long hills, but I still thought it was fine. And it had no trouble pulling OD at 70 mph on flat land even with that load. If you only hauled loads like that 4.10 gears might be better even with a 351, but I really liked the 3.55s I had.

I don't have any experience with the 300. People say spinning it faster just uses more fuel without really giving more power, so I'd be tempted to go with 3.55 gears there as well. But that's just a semi-informed guess.

 

Thank you for the in depth details! Mainly in looking for more grab and go. I never tow anything so towing isn't much my I do drive a lot as far as high way sometimes but not a lot.

 

Get 4.10s out of an Explorer or Ranger. Google Ford rear axle gear ratio codes, find a list, write down every code with 4.10s and 4.56s and then hit the junkyard looking at the door sticker of every Ranger and Explorer. When I went looking I found that about one in ten had 4.10s.


I agree that there's no point to spinning the 300 faster than 2500 or so at cruising speed.

I'm about to swap in 4.10s with 31s. That gear:tire ratio is about what every truck that was sold "for towing" in the 80s and 90s came stock with. I'd personally much rather be speed limited by deep gears and high RPMs than not have deep enough gears.

I wouldn't tow anything more than a jet-ski with an E4OD in OD. It's just making a lot of heat and being hard on the transmission (particularly the torque converter clutch) for no good reason.

 

Everyone who knows anything about E4ODs (including Mark Kovalski, former Ford auto trans engineer who's on here a lot) agrees that towing with the E4OD in OD is fine, it was designed for it. And an auto trans generates very little heat when the torque converter clutch is locked. Now if the trans keeps needing to downshift and can't keep the clutch locked, then yes, you should take it out of OD. But as long as it can easily pull OD there's no reason not to

 

That's true, but few stock trucks will be holding OD with the torque converter locked while towing any sort of a load (larger than a jet ski) and stock gears, you'll just be lugging it down to ~1k and then downshifting at every little hill. Maybe it would work better across a really flat part of Kansas or something but nowhere else.

 

Aside from ratios, before you pull the gears from the Explorer check the backlash and tooth contact pattern. Try to set it up the same in your rear axle.

 

Which is why I said...

I guess I didn't say it explicitly, but I think it's pretty clear that I didn't pull the Colorado Rockies in overdrive. But that's what 3rd gear is for (and sometimes 2nd). But from Minnesota I could keep it in OD for almost all of the drive through southern MN, through Iowa, across Nebraska and even across all of eastern Colorado. Turns out a lot of the country is a lot like Kansas.

 

Yeah, I assumed you didn't pull the rockies in OD. FWIW I'm talking about small rolling hills. You can stay in OD sometimes but you wind up losing speed and lugging it. Sometimes the hill is long enough it down shifts. I say just use 3rd the whole time in that case, drive-ability will be better too. I picked Kansas because it's statistically the flattest state (for a given area a the average section of Kansas will be closer to level than any other state, it's one of those pieces of trivia you never forget ). Obviously 3.55s and a 351 are better than 3.08s and a 302 for staying in OD but my opinion is that if you can't stay in OD basically all the time then go for third (obviously make an exception for that one big hill on an otherwise flat route).

 

We're thinking pretty close to the same. But for instance driving across South Dakota there are MILES of flat followed by a short hill and then more flat. The 3.55 gears let me pull OD across the flats and then every so often I'd have to take it out of OD for half a minute. Using OD like that is well worth it for me. But if you'd prefer to leave it in 3rd, that's OK too.

And a little off topic, but that truck did something that made driving like that easier. I was using the speed control and as it went up hills it would slow down, but it wouldn't downshift. So when I noticed the speed drop off I'd kick the speed control off and kick it out of OD until I topped the hill and got back up to speed. By contrast my current truck (460 and 4.10 gears) will downshift and snap everyone's necks as it maintains whatever speed I set. So I end up not using the speed control with my current truck unless it's empty. I actually found the 351/3.55 gears MUCH better for the hauling I do than my 460/4.10 setup.

 

That kind of situation is where I'd say go for OD, the rolling hills where you can top most of them in OD but just barely is where I'd want to use 3rd. I'm working on installing cruise control in my truck so I'm waiting to see how well it handles downshifts and stuff. The cruise control in a CR-V I had was very downshift-happy. You could get near WOT before it downshifted under normal operation but with cruise control it would downshift at practically anything.