I went to the Dodge Parts Dept. ordered the diff fluid they insisted that I use 75-90 I read here that I should use the 75-140 and that I should use the conditioner in whether I have an open or posi.

This is an 04 Laramie Quad 5.7, He also stated that I have the key with the chip I was under the idea the 04 didnt have the chip

Thanks

 

depends on which rear end you have. check on the rear axle tube just inside the right wheel, should be a wrap-around tag telling you which diff you have. the 9.25 rear end is the only one that requires 140 (which you are likely to have if you have a 1500), the rest are 90 (including front axles).

I think by conditioner you mean friction modifier. The friction modifier can be added to non LSD diffs without a problem, and NEEDS to be added to LSD diffs.

 

The 140 is for the 9.25 rear and the 90 is for the front. Friction modifier is a must for the posi rear.

 

Thanks it is the 9.25 rear the rest of the tag is hard to read if it is Limited or Posi, I will go back and swap it out.

 

4oz of modifier for the posi rear when you do the change.

 

I have an 04 with the chip, part of the security package on the SLT, standard on the Laramie. The gray key has the chip, the black key does not.

 

w00t, black key!! you just made my day

 

Well I went to swap out the fluid the 75-90 is $20 a qt and the 75-140 is $30 a qt I got my money back and decided I am going to look to get some Amsoil instead thats ridiculus Dodge can keep it.

 

Only the Dodge stock LSD needs the friction modifier if it has the clutch packs.
4oz is the recomendation.
Don't forget to drive in a few slow but tight figure of 8's to get it all mixed in with the diff oil.
Oh yes and btw, don't drive in tight circles and corners giving it gas to burn rubber with the stock clutch type LSD.
This is DEFINATELY what screws our retaining clips in the clutch packs, acording to my rear end specialist.
Al.