91 Ford Explorer Rear Differential Problem

fordtrk91 · 07-18-2008, 07:38 AM

I need the rear diff fluid changed which isn't the problem. The car has about 150k mls and Im being told that even if I change the fluid, whatever "gook" has been holding things together may start to break off. If that were to happen, it would just make more sense to get a new car. Is this true?? Also the plugs for the diff are stripped. Please advise on what makes the most sense and what I'm in store for.

SABL · 07-18-2008, 08:23 AM

That's a new one on me....where would the "gook" come from? "Gook" or sludge normally is formed in the engine where combustion takes place and due to the crankcase having to "breathe" can draw in water vapor thus causing sludge. You should not have much sludge, if any, if the vent cap is intact on your differential. I say change the fluid with the recommended type and fix the plugs.

Your local auto supplier can help with the plug repair...kits are available. Any repair/s you make will be far cheaper than a new car. New cars are nice but &&&

My ride has 235K and runs strong....but it sure loves gas!!
1995 E350 5.8L

dcraker · 07-19-2008, 04:38 PM

Hmmm... there has only been one time where I heard that changing the fluid was bad in the car.
It goes back to 1993, where my friends brother got his first car from his mom.
I think it was like a Escort wagon. When he got the car, he thought it would be a good idea and go through the car and do all the PM on it.
Engine Oil change
Tranny fluid change
Radiator fluid
Air filter and couple of other things.

His mom had never done any of these changes when she had the car for 11 years bought brand new. She never raced the car and never really took it anywhere other then around the city. The car never (noticably) gave her any problems whatsoever, and her son had already been accustomed to it as well.

After he did all the PM, within a week or two, he had more and more problems with the car. It finally became a crap car.

So, if this sounds like your truck, where no one has ever done any thing to keep up with the regular maintenance. Then I would change things over slowly... much like you would for fish in a tank, replace some and leave the other water, until you feel confidence in changing more and more until everything is the way it should be

BUDFAN8 · 07-20-2008, 12:34 AM

changeing fluids hurts nothing if you change the fluid and it breaks then most likely it was on its last leg anyway.

ive heard many people talk about getting trannys from junkyards and saying dont change the fluid and filter. i think that is wrong as i said if that tears it up it was not a good tranny in the first place and it needs to go out before the 30 days most places give you anyway.

Bud.

SABL · 07-20-2008, 03:45 AM

Changing fluids will not cause any harm. But like Budfan said it will often expose problem areas from lack of maintenance. One of the biggest problem areas is the cooling system. When you don't change your coolant (antifreeze) on a regular basis and decide to flush the system with a "cleaner" and refill the system you are begging for problems. Most antifreeze products have a rust/corrosion inhibitor which protects the cooloing system. As the antifreeze ages it loses the ability to protect the system from rust/corrosion and your system is going to "wear" or start deteriorating. Flushing the system with a chemical agent will cause further damage to a compromised cooling system and I'll bet you'll be replacing a heater core (or even a radiator) soon afterward.

The best prevention is proper maintenance at the right intervals.

I'm getting kinda off-topic so I will make one last suggestion to fordtruck91:
Remove the rear cover from the differential housing (not difficult) and repair the damaged threads on the fill plug/s IF it is the threads in the cover or housing unit. Your local auto parts store will have the tools and parts needed for the repair. The reason for removing the rear cover is to make sure you don't contaminate the differential with metal shavings (a real no-no) and you can inspect the gears for wear or chipping.

If you need further assistance please post back to this thread and I'm sure Bud or I or someone else can get you through this ordeal. If you don't need any more help please post back letting everyone know what the "fix" was so others can benefit from the knowledge.

Marc .....aka SABL

07-18-2008, 07:38 AM	#1 (permalink)
fordtrk91 Registered User Join Date: Jul 2008 Posts: 1 OS: XP	91 Ford Explorer Rear Differential Problem I need the rear diff fluid changed which isn't the problem. The car has about 150k mls and Im being told that even if I change the fluid, whatever "gook" has been holding things together may start to break off. If that were to happen, it would just make more sense to get a new car. Is this true?? Also the plugs for the diff are stripped. Please advise on what makes the most sense and what I'm in store for.

07-18-2008, 08:23 AM	#2 (permalink)
SABL Registered User Join Date: Jul 2008 Location: Galena, Ohio Posts: 82 OS: WinXP SP3	Re: 91 Ford Explorer Rear Differential Problem That's a new one on me....where would the "gook" come from? "Gook" or sludge normally is formed in the engine where combustion takes place and due to the crankcase having to "breathe" can draw in water vapor thus causing sludge. You should not have much sludge, if any, if the vent cap is intact on your differential. I say change the fluid with the recommended type and fix the plugs. Your local auto supplier can help with the plug repair...kits are available. Any repair/s you make will be far cheaper than a new car. New cars are nice but &&& My ride has 235K and runs strong....but it sure loves gas!! 1995 E350 5.8L

07-19-2008, 04:38 PM	#3 (permalink)
dcraker Registered User Join Date: Jan 2008 Posts: 60 OS: Windows 2000	Re: 91 Ford Explorer Rear Differential Problem Hmmm... there has only been one time where I heard that changing the fluid was bad in the car. It goes back to 1993, where my friends brother got his first car from his mom. I think it was like a Escort wagon. When he got the car, he thought it would be a good idea and go through the car and do all the PM on it. Engine Oil change Tranny fluid change Radiator fluid Air filter and couple of other things. His mom had never done any of these changes when she had the car for 11 years bought brand new. She never raced the car and never really took it anywhere other then around the city. The car never (noticably) gave her any problems whatsoever, and her son had already been accustomed to it as well. After he did all the PM, within a week or two, he had more and more problems with the car. It finally became a crap car. So, if this sounds like your truck, where no one has ever done any thing to keep up with the regular maintenance. Then I would change things over slowly... much like you would for fish in a tank, replace some and leave the other water, until you feel confidence in changing more and more until everything is the way it should be __________________ Thanks, David If you cover it in chocolate, it'll look better.

07-20-2008, 12:34 AM	#4 (permalink)
BUDFAN8 Registered User Join Date: Apr 2007 Posts: 189 OS: XP	Re: 91 Ford Explorer Rear Differential Problem changeing fluids hurts nothing if you change the fluid and it breaks then most likely it was on its last leg anyway. ive heard many people talk about getting trannys from junkyards and saying dont change the fluid and filter. i think that is wrong as i said if that tears it up it was not a good tranny in the first place and it needs to go out before the 30 days most places give you anyway. Bud.

07-20-2008, 03:45 AM	#5 (permalink)
SABL Registered User Join Date: Jul 2008 Location: Galena, Ohio Posts: 82 OS: WinXP SP3	Re: 91 Ford Explorer Rear Differential Problem Changing fluids will not cause any harm. But like Budfan said it will often expose problem areas from lack of maintenance. One of the biggest problem areas is the cooling system. When you don't change your coolant (antifreeze) on a regular basis and decide to flush the system with a "cleaner" and refill the system you are begging for problems. Most antifreeze products have a rust/corrosion inhibitor which protects the cooloing system. As the antifreeze ages it loses the ability to protect the system from rust/corrosion and your system is going to "wear" or start deteriorating. Flushing the system with a chemical agent will cause further damage to a compromised cooling system and I'll bet you'll be replacing a heater core (or even a radiator) soon afterward. The best prevention is proper maintenance at the right intervals. I'm getting kinda off-topic so I will make one last suggestion to fordtruck91: Remove the rear cover from the differential housing (not difficult) and repair the damaged threads on the fill plug/s IF it is the threads in the cover or housing unit. Your local auto parts store will have the tools and parts needed for the repair. The reason for removing the rear cover is to make sure you don't contaminate the differential with metal shavings (a real no-no) and you can inspect the gears for wear or chipping. If you need further assistance please post back to this thread and I'm sure Bud or I or someone else can get you through this ordeal. If you don't need any more help please post back letting everyone know what the "fix" was so others can benefit from the knowledge. Marc .....aka SABL