Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Ford Explorer Community - Maintenance - Modifications - Performance Upgrades - Problem Solving - Off-Road - Street
Explorer Forum Covers the Explorer ST, Explorer Sport, Explorer Sport Trac, Lincoln Aviator, Mercury Mountaineer, Mazda Navajo, Ford Ranger, Mazda Pickups, and the Ford Aerostar
I have a spare front axle that I was told had 3.73's in it. With my luck it has 3.55's. I was wondering if there was a way to tell what gears it has in the pumpkin, when it is out from under the vehicle.
Is there a tag on the third member bolts? Or do you just have the housing? The tag will tell you what the gears are. On the bottom of the tag, there should be a combo of numbers. This is the axle info as originally installed. The bottom line will have the ring gear size then a space. Next will be an L for a limited slip diff if it has one, more space then the ratio listed closest to the bolt hole.
If you do not have the tag, count the rotations of the pinion verses the shafts. This will get you close enough to get a good idea what ratio you have. I think 1 gen explorers were only available with 3.27, 3.55, and 3.73 in 4x4 applications. Some 4x2s had a 3.08 rear end but I'm not positive.
Remove the differential cover, mark one of the teeth on the ring gear with a marker and then count the number of teeth.
If you find 39 teeth on the ring gear, then its a 3.55 - else, if the ring gear has 41 teeth, then its a 3.73.
But going off on a tangent (and to be picky about it): the teeth count doesnt actually determine the actual gear ratio because the teeth is there only to provide a mechanical interface between the two gears (prevent slipping). In other words, using the teeth count only determines the average gear ratio. The actual gear ratio is determined by the radius of the gears at the point of contact. As such, a gear ratio isnt fixed because ring and pinion gears, when simplified (teeth removed), are two conics sections rotating against each other at a right angle - so you can actually vary the gear ratio depending on where the gears contact each other (which is the foundation of most CVT transmission design except there's maybe a belt in between the two gears). If you have a 3.55 gear set, depending on how the ring and pinion gears are located relative to each other, you could have say a 3.56x, or a 3.54x.
Almost all 91-94's 4WDs came with either 3.27's or 3.73's.
Some 2WDs came with 3.08's, but these were likely XL base models with little or no options.
There probably ARE a few out there with stock 3.55's and even 4.10's, but they were extremely few and far between.
Of course, this is assuming the diff still has the stock gears in it. People do regear these things, so unless you know for sure it came off a stock Explorer and was never re-geared, it could have any possible gear ratio set in there.
If it is stock, there's about a 99.9% chance it's either a 3.27 or 3.73.
Actually quite a few of the first gens did come with 4.10. I had the option of picking a 4.10 setup when I started my conversion, but I already had the 3.73 front end.
The gears that are hard to come by seem to BE 3.55's.
Also my truck HAD the 3.08 and it was an optioned up 2wd XLT. Stupid gears are a dog. Why in the world would Ford be so dumb as to try and move a 5200 lb truck with an already weak transmission and then dump a very high gear ratio rear end in it?
I've heard stories, but have NEVER seen any actual proof of a 91-94 with factory 4.10 gears. 3.27's were standard, 3.73's were the "performance axle" option.
I've never seen or heard of any with factory 3.55's, either, which wouldn't make much sense anyway between the two standard gears, although it does seem with the 5 speed that 3.55 gears might be just the thing.
3.08's on a 2WD make some sense, since the torquey 4.0L can push the tall gears, and in the southern and western states with low lands and open highways, it would give higher mileage and better highway performance. I would say the 3.27's would have been enough, but maybe the 3.08's were only available with stock 225/70R15 tires.
I contacted the guy I got the axle from. He said the axle was from a 93 explorer and it had 3.73's. The axle was missing the original tag with the axle info on it. Thanks for all the information guys.
try to explain better to get the 3.73 axle ratio eg you count the teeth of the crown teeth of the sprocket teeth and divide eg crown tooth pinion axle ratio =
cerco di spiegarmi meglio per ottenere il rapporto al ponte es 3,73 dovete contare i denti della corona i denti del pignone e dividerli es denti corona :denti pignone =rapporto al ponte
I try to explain better to get the 3.73 axle ratio eg you count the teeth of the crown teeth of the sprocket teeth and divide eg crown : tooth pinion =axle ratio
I have two explorers with the 3.55 ratio. They are both factory 5 speeds, one 4x4 and the other 2x4. All the rest have 3.73 limited slip (rear) axles. The 3.08 was designed for economy and for the "flat" states. I don't think you could get it new in say.. Colorado, without special order.
To my understanding, I could be wrong, Ranger 4x4s with the 2.3L 4 cylinder had an optional 4.10 gear ratio. I don't think it was available any other way normally. They used the dana 35 housing but it used dana 28 internals. So its not a good swap for the Explorer's 4.0L.
Yeah, well the 3.08 is a dog even in the "flat" areas of Houston...our highways are built taller than most hills in Dallas. With the 3.73 in I feel a little more capable.
BTW, my 92 2wd has 3.27 gears and the 5 speed, I goofed.
I'm sure the 3.08 is a terribly sick dog. I love the acceleration of my 3.73 trucks compared to my 3.27. I think explorers should have been built with 3.55 as the minimum. I wish they would have offered 4.10 and 4.56 as options.
I'm pretty sure there was an industry minimum economy average that auto makers had to comply with then, I think it started in the early 80s. All Ford offered the 3.08 for was to get the best mileage ratings to keep within the federal mileage standards for that vehicle type. This was how they kept the average fuel economy above the minimum for all models companywide, even though most explorers were not built this way.
