1996 F-150 4WD with limited slip in the Front Differential, since there is no drain plug what is the best way to remove the old fluid and replace with new ? Any suggestions about synthetic upgrades ? Thanks !

 

Unless you are 100% sure, or know of aftermarket upgrades, I would re-double-check to make sure that you have a limited slip up front - they were pretty rare from the factory. Double check your axle code on the VIN sticker and cross reference it.

But regardless if it has the limited slip or not - 75w90 gear oil is the spec for the front. If it is a limited slip you need to add XL3 friction modifier. I used Mobil 1 synthetic 75w90 on both my front and rear and have no complaints. The only way to change the fluid without pulling the entire pumpkin is to run a long tube into the fill hole and pump it out.

 

Something like I imagine would be handy.

I just pulled my pumpkin today. To drain it, I undid all the bolts except the top, cracked the seal and let it trickle for an hour or so. Not sure how you'd seal it back up if you were only doing fluid, but I'm regearing mine (hence pulling it out).

I would highly recommend drilling and tapping for a magnetic plug once it's drained.

 

If you have a removable cover, pull it, otherwise you can get a low cost suction gun. The suction gun has worked great for me.

 

This caption & the NEXT several explain how to add a drain plug:


(phone app link)

Use the factory-recommended lube. If you don't have a Haynes, read this caption:


(phone app link)

When you have one, read it cover-to-cover at least once. This explains how to read the VC label, and fill in your signature:


(phone app link)

This shows the front axle sticker, which you should document ASAP before your truck's becomes illegible:


(phone app link)

 

Thanks for the reply, it was ordered from the factory with the limited slip in the front differential and the factory code confirms this. Guess I will have to find a way to pump out the old to replace with new upgraded synthetic and friction modifier.

 

Yes it would, probably head to Harbor Freight and see what they have available.

 

No removable cover so it will be the pump out method. Why the Ford engineers didn't install a drain plug. No common sense

 

Dana didn't put a drain in it because it's so easy to siphon, and it can't leak that way. Very sensible, if you have to warranty what you build & sell. There's no drain in the rear diff, either. Or the gas tank. Or the PS, ATF, brake, or refrigerant fluid systems, either. None of them needs to be drained so frequently & thoroughly that they'd benefit from a drain plug.

 

I know others might disagree with this but I would use a quality conventional gear oil not a synthetic. If the front diff has any oozes the synthetic gear oil will clean them up and turn to a leak. I can hear someone chiming in that the ooze should have been fixed but really our trucks are getting older why add one more item to repair if it's not necessary.
Drain plugs on diffs and transmissions make service so easy, why add one to the front diff if not for this reason!
Good luck on the project