100k rear diff oil change in ford f150, I think not.

[JustinH]

My 98 f150 4x2 nascar edition just turned 50k miles the other day. I'm pretty nuts about maintenance. I had the day off today and decided to put new brake pads on it, repack the front bearings, and change the oil in the diff.

I've been waiting to put my internet ordered Royal Purple diff oil to the test.

I was pretty shocked to see the condition of the rear end oil at 50k. It was black, and mucky looking. The previous owner towed his boat, and it looks like the diff was overheated and it was just generally a mess. Ford says the rear end is a 100k change? I would say 35-40k at most. Once a year if you do any towing.

Don't forget about that diff.

I went with the royal purple stuff because it got it on ebay pretty cheap, and it already has the friction modifier in it so I don't need to buy a seperate bottle at ford.

 

[TallPaul]

I agree that 100,000 is way too long for factory fill diff fluid. I would think one would want to get Redline in there asap. Maybe 5 to 10 thousand for break in and then switch it out. Redline maybe could stay in there a long, long time, but probably good to change that every 50,000.

OTOH, my old '84 F150 (sold to friend) has 225,000 miles on original diff fluid. Seems to be working fine.

 

[Spector]

We rarely hear of a differential failing regardless of the reason. Even under total abuse and no changes the oil seems to do the job

 

[1sttruck]

Dodge is schizo about the 2003 axles on the 2500/3500; no oil change noted in the manual out to 120k miles with normal service, and oil chnages every 15k miles with severe service.

 

[Schmoe]

Justin...you got the LS rear-end? I heard that even with RP, RL or Amsoil, there isn't enough FM in it to stop the rear end from shuttering. What's your take???

 

[Korean_redneck]

My friend has a 1997 Kia Sportage with 150,000 miles with the original Diff and Transfer case oil, your suppose to change it at 30,000 miles.. but nothings wrong haha.

 

[Al]

quote:

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Originally posted by Spector:
We rarely hear of a differential failing regardless of the reason. Even under total abuse and no changes the oil seems to do the job

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Exactly. But I'd still change at say 50K miles or so.

 

[JustinH]

quote:

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Originally posted by Schmoe:
Justin...you got the LS rear-end? I heard that even with RP, RL or Amsoil, there isn't enough FM in it to stop the rear end from shuttering. What's your take???

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My truck has a 3.73 open rear end, so I can't comment on that. Thanks for the tip, I might add some to my car when I do it, which has a limited slip rear end.

 

[DirtyApe]

Earlier this year I made the mistake of buying a 2000 Ford Explorer XLT with the 4.0SOHC (BIG mistake), but the rear end was the "lifetime lubed" differentials. Yea right, the outside of the two halves was soaked with oil at 83k and was half empty.

 

[JohnBrowning]

Best policy is to change ever 2 year of 24,000 maxium. If you tow etc.... once a year or 12,000 miles. If you use a good synthetic and do not tow often 50,000 is not too bad but not my idea of good maintence. 100,000 miles is funy. A lot of people get away with it but most do not two often either or they are towing very light things!! I used to see and hear about all kinds of rear end failures on GM "S" Blazer's and 1/2 ton CK fullsizes. The pinion gear's were always pitted and corroded, the covers were always blistered and rusty. The problem is that it always happens out of warranty.

 

[AstroVic]

I have Royal Purple in three Ford differentials - two with limited slip. No friction modifier was necessary in any of them and they are quiet as a mouse.

Also, your differential fluid was probably a mess because the previous owner towed his boat, which makes it very likely that it was submerged more than a few times. Ford requires the differential fluid to be changed any time it's submerged in water.

 

[medic]

My '97 F150 has a lifetime fill in the rear differential for normal service. For severe service it calls for a change at 100k.

 

[AstroVic]

quote:

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Originally posted by medic:
My '97 F150 has a lifetime fill in the rear differential for normal service. For severe service it calls for a change at 100k.

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Unless it's been submerged in water.

Ford (and all other auto manufacturers that I know) require the differentail fluid be changed if the housing is submerged in water.

If the guy towed his boat and backed it into the water and pulled it out of the water at a boat ramp, that's a likely cause of the nasty looking differential fluid.

 

[Jimbo]

quote:

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Originally posted by Spector:
We rarely hear of a differential failing regardless of the reason. Even under total abuse and no changes the oil seems to do the job

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Maybe so, but it does happen. My used F-150 had destroyed gears and bearings at just over 100,000 miles. The fluid was black and almost "chunky", like spoiled milk in texture.

As for RL not having enough FM additive in it, RL eliminated the chatter in my BMW axle. It had M1 in there before. Castrol, M1 and Valvoline dont have enough, even if they state that they are ok for LS applications.

 

[JustinH]

astrovic, I think you nailed it on the head.

I never thought about how they get the boat into the water because I don't have a boat, but it makes sense.

Glad I got that taken care of, and no boating in my future so I'm good for a while on that rear end.