RP or Amsoil 75w90 in Nissan LSD

[Jefr00]

I'm a long time lurker, first time poster here. I want to change out the fluid in the front and rear diff's in an '89 Pathfinder, but I'm a bit confused as to which gear oil to use. Royal Purple has the 75w90, but the Amsoil choices confuse me. According to the product selector, Amsoil says I need an 85w in the front diff and an 80w90 in the rear LSD. The factory manual says 75w90 is fine for the front, but makes no recommendation for the rear, other than "LSD Rated". So, can I use 75w90 for the front and rear? What are the potential problems? The truck lives in the Northeast, 500-600 miles weekly, 75% highway/15% surface street/10% rough or unimproved roads. Both RP and Amsoil are available locally, so that's what I'd like to use. Both are GL-5 rated. Also, the Amsoil product selector calls for a 75w90 GL-4 in the transfer case. Can I use a GL-5 rated there as well? Thank for reading.

 

[Steve S]

Redline or mobil 1 gear oil.

 

[HardbodyLoyalist]

Usually, you run the same fluid in the transfer case as you run in the transmission. For Nissan's, this should be a GL-4 or multirated GL-4/GL-5. Some people use ATF in their transfer cases:

http://www.nissanoffroad.net/messageboard/topic.asp?TOPIC_ID=10731

You certainly do NOT want to run straight GL-5 in your tranny. I suspect the same thing applies to the transfer case.

 

[JohnBrowning]

I would choose RP over Amsoil any day! I am useing their MaxGear Gl4/GL5 rated lube in my Trany and it is doing just fine!