was under the truck the other day and noticed my diff didnt have a gasket. there was silicone coming out of the joint so its sealed up. this got me to lookin and i found another tag besides the carrier and gearing tag. it said 5W140 synth only. i know wut it means but thought it to be kinda wierd. possible aftermarket accessory in there or just a stock tag?

 

Are you sure the tag doesnt say something like 95W/140 ? I have never heard or a 5W/140.....
Generally the higher viscosity gear lube is required where a differential will produce more heat than usual such as during towing or offroading. The use of synthetic gearlubes work very well in this application.

OR 4x4

 

about the no gasket MOST people never run a gasket on the diff just RTV sealant. alot of people do this personally I am very nerotic and when i replaced my diff i put RTV on a gasket, so its doubled up.....thats just me

 

Yeah I havent seen many people who put a gasket on it, like Zach said just use the silicone. Zach is a nut though and always has to go that extra mile, hahaha.

And as far as synthetic gear lube, I agree. If you are gonna go to the trouble to drain the fluid then you might as well put good stuff in there thats gonna last.

 

i know about the not using gaskets. i think they are more of a pain then anything. what i was asking was the tag stating the lube. never seen one like that and was just wondering if that meant something wasnt stock. you dont just go and slap a tag on something just because you changed the oil.

it may have said 95w140. i had to scrape off a layer of grime to read it.

 

put whats recomended for your rear end in. if it already has synthetic then use synthentic agian

 

so wuts reccomended for the stock rear-end?

 

why are u asking these peeps? they drive rangers man...try fordtruckworld, they are mostly 97 and up effers.

on the gakset and RTV thing, ford techies i talked to said ford says to use just RTV.

 

that up in the air we did at the dealer use gaskets and RTV. but if the gasket wasnt in stock we just used RTV...its like a toss up

 

ya i use RTV since i used to like the slop and i changed my diff fluid often. plus the RTV seemed to hold up better.

 

that 5w140 is what you use with the additive slip lock, thats what my dads truck uses.(his is 98 f150 4x4)

napa carries it or the ford dealer. and use synthetics.

 

use amsoil severe gear oil... i changed mine to this and i noticed a difference in pemp and gas mileage... its the best stuff out there