Gear & t-case lube?'s

What gear oil to use for the CJ diffs ?...they aren't stock and the rear
has a Detroit locker. Also, in the TJ I use brake cleaner to spray them
out after draining...can I do this with the locker?

And what to use for the t-case? Dana 300 & T5 manual tranny. It's calling for 85w-90 gear lube I use ATF + 4 in the TJ. I'm reading the
t-case and tranny have to be done at the same time since they are connected.

Thanks for any advice.

V-

Detriot says you can use 90. I like to use lucas, not needed but I just like it. You dont have to change the trans and 300 at the same time. The 300 is sealed then the trans it bolted to the 300 and that is what seals it. The 300 takes 90 and I have never looked into the gear oil in a T5 but I am pretty sure it is 90 also. I have been told that the brake fluid eats the seals, not sure if it is true, but brake fluid won't affect the detriot at all.

chics4jeeps wrote:

What gear oil to use for the CJ diffs ?...they aren't stock and the rear
has a Detroit locker. Also, in the TJ I use brake cleaner to spray them
out after draining...can I do this with the locker?

And what to use for the t-case? Dana 300 & T5 manual tranny. It's calling for 85w-90 gear lube I use ATF + 4 in the TJ. I'm reading the
t-case and tranny have to be done at the same time since they are connected.

Thanks for any advice.

V-

Hey V the diff's can used plan old 85w-90 (or 80w-90 no sure whats the difference) The TJ (NP-231) used ATF (mercon 3 or better) cause it is chain driven and the planetaries for low range don't move as much and heavy gear oil is not needed. Dana 300 is fully gear driven like the manual trans of a car. Thats why it uses 80w-90. I'm unsure about the gear oil for the T-5 I would think uses 75w-90 like the AX15 (YJ and some TJ transmissions) and many others. The trans and the T-case in the CJ do not share oils. They are sealed out from each other. Thats why you hear people talking about the spline counts on them and which ones are male or female inputs and outputs.

Check out this thread read the last post. T-5 have a lot of opinions on what to use. Do not use a GL5 oil. I have a T-177 and use redline MT-90
the diff and transfercase 80 - 90
http://jeepsunlimited.com/forums/showthread.php?t=822355&highlight=T-5+oil

Kewl lots of info I have a couple of quarts of Valvoline DuraBlend synthetic 80w-90 so I'll use them up and go shopping for more..reading
jeepforum, the opinion is use redline mt-90 and no gl-5 as well.

Thanks for the help guys.