hey guys, I was looking at my ID sticker in the door and it says that the differential in my truck has a code of H9. I've been looking around and I've read that the H9 is the 3.55 ratio with the limited slip. Is this right?
Thanks, I actually found something similar to that chart when I later on searched on Google, but nothing with as much information. Alright, so I've got an H9 3.55 limited slip, so next question is lubes. The chilton manual says to use an 80w90 synthetic while the owners manual says to use 75w140 (I'm guessing dyno). Does it really matter which one of these I use? I've been looking around and can only find the 75w140 in brands that I've never heard of and am weary about putting an unknown brand in my truck. I was told by the guy at O'Reileys that if I used full synthetic that it wouldn't really make that much of a difference...is this true? Which brands do y'all like the most?
My truck is out of warranty, if that makes a difference.
I just visited the local Ford dealership and told them what I have for an axle which, by the way, is identical to yours. They gave me Motorcraft 80-90. Don't forget to pick up 2 bottels of friction modifier for the limited slip. Just add it to the rear when you fill it. Comes in 4 fl oz bottles. Use both.
89 F150 3.55 LS
I know the dealership is a wee bit more expensive on a lot of supplies, parts, fluids, etc. but it bugs me when I go into a chain auto parts store and get blank stares on what should be a simple question. Not all are like this but I have come across this a lot.