Mechanics

REAR DIFFERENTIALS WI

1994 Ford Explorer

Drive Train Axles Bearings problem
1994 Ford Explorer 6 cyl Four Wheel Drive Automatic 275000 miles

I have a 1994 ford explorer with roughly 275 thousand miles on it. Its mostly just a backup vehicle and I want to convert it into a mud toy. But I encountered a slight problem. I was driving it home one day about a month ago and it stopped transfering power to my rear wheels. I got it towed home and was checking it out and my driveshaft still spins with the vehicle in gear and when the rear tires are jacked off up, you can spin the tires and it causes the driveshaft to spin (with the transmission in neutral) So by process of elimination I know the problem is in my rear axle someplace? But my question is do I just need to replace the axle shafts or am I going to have to replace the whole differential gears or both and how can I tell? And if I have to replace the differential gears (or spider gears I've heard it called both) how do I go about replacing those or is it a job better left to a professional? Or would it just be easier to swap a whole axle casing with all the axle internals already in it? This is my first time working with this problem so any and all help is greatly appreciated thank you!
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Bender122288
May 16, 2009.




It sounds as if you may have a broken pinion shaft (the shaft that the " spider" gears are mounted on, Start by removing the rear cover, and see what is out of place.

Most of the parts in the rear are wxpensive to buy new. A used rear may be in order. If you do opt for a replacement rear, be advised that you must get the SAME axle ratio as you are replacing, or you will be in for a BIG surprise the first time you engage the 4-wheel drive!

Let me know what you see upon removing the rear cover.

Tiny
Jgarofalo
May 17, 2009.
I've already had the cover off the rear end and to my visaual inspection nothing seems to be out of the ordinary except for the fact that what u spin the rear tires everything inside the " pumkin" kind of wobbles and I noticed the big gear on the left side (unsure which name it actually has but the teeth are horizontal and its the biggest gear in the rear end)but also now I have the rear end yoke removed along with the driveshaft and prior to removing this the rear end locked up as it was being pulled with another vehicle to move it into the garage and it will not move in a forward direction at all when even pulled by another vehicle. But the rear tires still spin backwards? How complicated is it to remove the pinion shaft and replace? Or am I way in over my head? I'm a beginner with major work like this and I want to learn and I appreciate all the help! Thanks!

Tiny
Bender122288
May 17, 2009.
OK, a basic primer.

The BIG gear is the RING gear. The smaller gear in front of it that drives it is called the PINION gear. The two larger gears that the axles go through are called SIDE gears, and the smallest ones are called PINION gears (confusing, but that is the way that the manuals refer to them) - but we call them " spider" gears.

When you removed the yoke, you removed the part that keeps the pinion gear from moving back too far into the ring gear. This is what causes it to lock up when you try to tow it. Put the yoke back on, and tighten it to keep the pinion in place.

Tiny
Jgarofalo
May 18, 2009.
Ok now I put that all back on and it towed fine. But the problem im still having is I cant figure out where my problem is? None of the gears that I can see look bad? The RING gear looks fine and so does the pinion gear? And so do the side gears and the smaller pinion gears? How can I determine where my problem is or am I just gonna have to replace or rebuild the entire axle and differential

Tiny
Bender122288
May 24, 2009.
Time to do a bit of troubleshooting. Start by verifying that the driveshaft is actually turning, and that the axles are not. Once you have verified that the problem is in fact the rear, remove the cover and observe with a helper. Watch the inside of the rear while a helper puts some load on the drivetrain (run the engine and attempt to move the car) - make sure to block the wheels and lock the brakes so that the car does not actually move and injure you!

The possibilities are: - the yoke could be cracked or stripped. In this case, the driveshaft and yoke will turn, but the ring gear will not.

- side gears could be cracked. In this case, the ring and pinion gears will turn but the axles will not.

- side gears could have stripped splines. Same as being cracked.

- Axle splines could be stripped. Everything will seem to turn normally, but the axles will not turn.

Since these are all direct mechanical connections, something has to be stripped or cracked. Don't overlook missing or broken teeth on the ring gear.

Tiny
Jgarofalo
May 25, 2009.
Just a thought will all my misleads in the axle and still being stumped? Is it possible for it to be the torque converter!

Tiny
Bender122288
Aug 19, 2009.
You have to figure out where you are losing your driving rotation.

The engine turns the torque converter.

The torque converter turns the transmission.

The transmission turns the transfer case.

The transfer case turns the drive shafts.

The drive shafts turn the differentials.

The differentials turn the axle shafts.

The axle shafts turn the wheels, and impart motion to the vehicle.

You need to examine what IS turning, and what is NOT turning.
AD

Tiny
Jgarofalo
Aug 19, 2009.
Well a friend of mine told me maybe im losing my power cuz my torque converter is messed up and not fully acting like it should cuz like I said it will move with very high rpm's at very slow speeds I had the diff cover off and had a helper (tires were blocked for saftey) and put it in gear and the driveshaft spun and the ring and pinion spun once it got up to those high rpm's. Spinning the driveshaft manually with the tires jacked up with spin the rear wheels and diff internals I can put the truck in neutral with the tires on the ground and cant spint he drive shaft without the truck trying to move forward. The reason my buddy told me it may be my torque converter also because when my truck is idling it tends to hop up and down in rpm's? If this gives u any further idea more help would be greatly appreciated

Tiny
Bender122288
Aug 19, 2009.
To start this off my explorer will only drive about 3 mph at about 3500 rpm.I've been told tranny issues I believe its rear end issues it I have a 94 ford explorer xlt with the ford 8.8 with 3.73 ratio and limited slip. Driveshaft would spin when in gear but not move truck. In neutral the driveshaft wouldnt spin (with tires on teh ground) jacked up the whole rear end u can spin one tire by hand and the other doesnt spin. Spin the pinion yoke/driveshaft it will spin one tire im ost please help me. And here is my rear end findings

well I pulled it all apart today removed everything but the pinion, and attached to the side gears are like 6 plates per side.I wanna say those are the clutch plates (if I remember correctly but not sure) for the LS. And once again if I remember right 3 of the 6 per side should have 2 tabs on it which slide into slots on the carrier. Well I only have one per side and they are closest to the side gear (on each side) I also recovered what seems like the remains of the other tabs in the bottom of the diff. And I see what looks like where the tabs were supposed to be. Could this be my problem. And I also decided to spin the pinion yoke b4 I removed the axle shaft and it still turned one axle shaft but not the other (this is with it out from the truck and sitting on jack stands) im just lost lol so if u can help me out it'd be super appreciated thanks

Tiny
Bender122288
Sep 2, 2009.
The plates are for the limited slip aspect only. When one wheel loses traction, the clutches transmit the torque to the other wheel.

One thing that I would like to point out.

Gears, splines, and direct mechanical connections do NOT slip! They either work or break. There is nothing in between. And when they break, there is always evidence - like loud noises, shavings, broken gear teeth, and the like.

If your transmission is gone, don't make the mistake of denial, and fixing every other part until the inevitable transmission repair becomes no longer deniable.

Tiny
Jgarofalo
Sep 4, 2009.

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