ok, i reposted under a new title due to the fact that i wasn't getting my specific question answered because it was under a different title. anyway, i've been trying to figure out if i have LSD or not. i got a new plug from the dealer yesterday, and i wanted to replace it finally. since i was gonna do this, why not remove the cover, clean the surface up, put the right stuff sealant on, and refill with a clean lubricant. i just need to know what to put in. i was gonna do 80-90 just like the manual says for 5 qts. i don't wanna jack this up b/c its too easy, i just need to know if i have LSD.

here is what i got from my glove box sticky note:

torque converter - lock
transfer case - shift-on-t
axle front, 3966# Dana
axle ratio - 3.55
axle rear, 3850# Corpo

i'm gonna double check my rear diff cover to see if i still have the tag on there. brb. tia

 

jack up the back of the truck, spin one of your wheels, the one on the opposite side will spin the other direction if you have an lsd... if the other wheel doesnt move, then you have an open diff

 

ok, i went out to my truck and jacked it up. i spun my left rear assembly and the right rear assembly moved in the opposite direction. sweet, now i know i have a LSD with 3.55. i just have to figure out what all this means now.


REAR AXLE—LIMITED SLIP DIFFERENTIAL
9-1/4 inch 2.2 L (4.7 pts.) 6
248-RBI (2WD) 3.0 L (6.3 pts.**)
248-RBI (4WD) 3.4 L (7.0 pts.)
267-RBI 3.3 L (7.0 pts.**)
267-RBI (4WD) 3.6 L (7.5 pts.)
286-RBI (2WD) 3.2 L (6.8 pts.**)
286-RBI (4WD) 4.8 L (10.1 pts.***)
** Include 0.05 L (0.25 pts.) friction modifier.
*** Include 0.19 L (0.4 pts.) friction modifier.
6 Include 0.1 L (0.2 pts.) friction modifier.
**** Includes 0.9L (1.0 qts.) for coolant reservoir.
*****Nominal refill capacities are shown. A variation
may be observed from vehicle to vehicle due to
manufacturing tolerance and refill procedure.

this is from the PDF manual that is posted somewhere on this forum. what the hell does this mean? i thought i had a 9.25, but not sure anymore. i checked for the tags on the back of the diff cover and there were not any. any way to figure out what axle i have?

well i guess it doesn't matter how many pints. i'll just keep filling it up by squirting it into the fill hole and once i see it, i'll know its good to go. at least 8 pts, and no more. my owners manual says 75w-90 but the PDF manual says 80w-90. will i mess anything up if i choose either one? i'll also get a lube the the friction added already. i'm gonna do this within an hr, so hopefully there will be more feedback before 2pm. tia.

 

you won't mess anything up by putting 80w-90 in. I just buy the friction additive separate i think its like 5 bucks and add the whole little bottle then you know you have enuff. then just fill with your diff fluid till she comes out the hole. btw you should have the dana 40 axle.

 

thanks dodgeboy. i'm heading out now to the zone to pick up the stuff.

what makes you say i have a dana 40?

 

so stopped by auto zone, they had vavoline, mob 1, lucas, and royal purple. holy hell, royal purple is $17 for one qt! anyway, lucas had the additive already in it, however; i was gonna buy mob 1 and add the additive myself. the additive brand was CRC 402508 Trans-X Posi Trac Limited Slip Gear Oil Additive. as i was about to buy it, i was reading the back and it said not to be used with automatic transmissions or ATF. how the hell is that possible? if it's in the read diff it won't know if you have automatic or not. so i didn't pick it up, i'll wait to do this on Sunday afternoon now. any ideas?

my best bet is probably lucas, since it already has it in there. and the guy said i need about 3 qts. the right stuff is gonna be sweet to use though, i've always used the "old skool" sealants.

 

lol all they mean is not to mistake it for the tranny additive. That sounds like the stuff you need for your diff. i personally like the lucas stuff but i'm sure someone will differ. Dana 40 is the generally the axle that Dodge put into these trucks.

 

I think it saying not to use it in an automatic transmission or with ATF. Not if your vehicle has an automatic. I believe it has a chemical reaction with ATF and breaks it down.

 

No offense, but thats incorrect. If you have an open diff, and you spin the driver's rear wheel one direction with the truck jacked up, the other wheel will go the opposite direction. If you have a LSD, the wheels will go the same direction.

 

Also wouldn't it make a difference if the truck was in neutral or in park?

With the rear end in the air and the truck in Neutral both rear tires will spin the same direction if you have a LSD.