I have a 97 F-150 4x4 and am wanting to change the transmission fliud, differentials fluid, and transfer case fluid. I am wanting to use Mobil 1 Synthetic. The truck has 95K on it now and the manual says "lubricated for life" am I asking for problems by doing this or better gas mileage/smoother operation?
I have already switched the engine to Mobil 1(5w-30) and a K&N oil filter. Gas milage was better immediatly! 12.7 miles per gal.
Any other recommendations for a new F-150 owner?

[This message has been edited by N. Narvais (edited 01-29-2001).]

 

Ditto what nomo said. I have Mobil 1 in the transmission and transfer case, and Mobil 1 in the front diff. My rear end requires 75W140 synthetic, which Mobil 1 doesn't make, so I used Amsoil in that. The Amsoil comes with the friction modifier for the limited slip already added. I changed all of the fluids at between 30K (transmission and transfer case) and 35K miles (diffs), and will do them again in another 30K or so. I recommend either the Mobil 1 or the Amsoil -- they're both good lubricants. Ford makes a synthetic rear end fluid as well, but at over $20/quart, it's outrageously priced.

I changed all of these myself except the transmission, which I had Jiffy-Lube do with my Mobil 1 fluid. They also dropped the pan and changed the filter. You won't believe how bad the rear diff fluid will look if it's never been changed, even though Ford says it's good for life.

I say go for it. Your truck will thank you.

Jon

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97 Expedition XLT 4x4, Black, 3.73 LS, 5.4L, leather, all options except LLS, Edelbrock IAS shocks, BFG AT KO 285/75/16s on American Racing Atlas 16x8

 

Thanks for the replies. I just found out today about Mobil 1 not making the 75w-140 for the rear. I have all the other fluids together and will get the Amsoil tomorrow. You also answered the question about the friction modifier I had.
I am really like this site. Easily the most active I have found.

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Sorry I missed it-
WELCOME to F150online!!

This is truly one of the best sites on the 'net!

 

Changing the fluid won't hurt anything. I've had the oil in the Expedition diffs changed 3 times now and it only has 51,000 miles on it. Just make sure to use the correct weights (diffs) & type (tranny) fluids. Also, use friction modifier if you have limited-slip.


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1997 4x4 Expedition- 4.6L, true dual exhaust w/Ravin DI/DO, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, 2000 F150 "XLT" wheels, 4.10 gears, Auburn LS, Clarion In-dash CD player, Smitty Bilt push bars and nerf bars.

2000 4x4 F250 SD XLT SuperCab SWB- 6.8L, Offroad Pkg, Camper Pkg, 4.30LS, Tape & CD player, Remote Keyless Entry, Sliding back glass, tinted windows, 265/75R16 OWL tires, Smittybilt nerf bars & Line-X bedliner.

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