I'm WAY past due on changing my diff fluid but I don't know if I need the friction modifier. How can I tell if I have a limited slip diff? My truck is an 07. It's the basic work truck model (LS) with a 4.7. Can I tell by the VIN?

Also, should I drain by removing the cover or just suck it out with a pump like dodge does?

Thank you.

 

Need to look at window sticker, build sheet, sticker in glove box or tag on rear axle to know if it's got factory LSD.

If it does, it's a clutch type which needs the modifier.

NEVER just pump out the old fluid. You really need to do a visual inspection of the ring & pinion, spiders, clips, etc. and look at the magnet when changing the fluid ESPECIALLY if you have the factory LSD.

Every dealership I've been associated with has pulled the diff cover to change the fluid. If yours is sucking it out the fill tube, it's time to look for a different place to have it done at...

 

Thanks a lot. For some reason my truck doesn't have the tag in the glove box OR on the rear end. Guess I'll have to call Dodge.

The first change I did pay to get done at the dealer because I assumed they were going to inspect the gears and I heard Dodge had a problem with rear ends (plus it was under warranty) but the guy told me they just pump it out. And they still charged me $130.

 

The rear ends are pretty solid, I've seen no indication where they are not as solid as a comparable sized Dana. The problem is the LSDs are crap!!!

 

It is my understanding that LSD equipt vehicles will not exhibit counter rotating wheel with no load, i.e, open diff action. So, jack up the front or rear, with the tranny in nuetral, spin a wheel by hand and observe the other wheel. If it rotates in the opposite direction, you do not have a LSD, but an open diff. If it spins in the same direction and spins the drive shaft, you have the LSD. I hope this helps.

 

Do a burnout cowboy!!!!!!

 

Does not work like that. I have LSD and the opposite wheel spins just like an open carrier which the OEM LSD is suppose to act like when no pressure is applied.
What makes the opposite wheel rotate tha opposite way are the carriers spider gears which all carriers have. Since it take an eunequal force to lock up the clutch plates, both wheels should spin freely and the idea of watching the other wheel is not going to help any.

You can request a build sheet directly from Chrysler and it should state whether or not it has LSD. LSD is an added option and is not standard on 4.7L work trucks, so if you've got a bare bone's 17" wheel Ram, chances are you dn't have LSD.

As for price$$$, You need 75w-140 which is a full synthetic. Cost is $20 per bottle. You'll need 2.25qts which is $60. Pour in 2.25qts and be done with it. The Mobil 1 LT has modifier in it already. I have been running straight up Mobil 1 without any extra Mopar modifier in my LSD rearend for 5kmi so far and have not had any issue's.