My local jeep dealer told me to use 10W-30 oil in my 97 TJ's manual transmission. The service advisor said Jeep put out a technical supplement a few years ago advising to use 10W-30 oil in the manual transmissions, which will aleviate the rough shifting. I changed the fluid in my tranny to 10W-30, and it is shifting much smoother, but there is alot more transmission noise. Has anyone used 10W-30 in their manual transmission? I just want to make sure I'm not going to have problems with premature wear from the 10W-30.
For years, the best fluid for AX-5 and AX-15 TJ transmissions has been Redline MT90. Some of us have been using it for almost 10 years. It is well documented that it runs great in the AX series manual transmission. It has the proper additives for the tranny and does produce the problems you mentioned.
Besides....none of the AX transmissions are under factory warranty any longer....does DC care if you kill yours by using engine oil?
When I had a manual I switched to Redline MT90 (Picked it up at a local race shop) and it fixed all my problems (same as yours). I'd spend the extra money for piece of mind because there is only one way you are going to find out if using 10w30 actually works or not...it is just not a risk I'm willing to take.
Check out my build thread: http://www.jeepforum.com/forum/showthread.php?t=503112
Getting ready to change the fluid in my 2003 Rubicon and am interested in hearing what is the best fluid to use in the NV3550.
I've recently changed to Royal Purple Synchromax. No better, no worse. Amsoil is also highly regarded.
On another note - I was told years ago (my cousin is a DC mechanic) that DC's Engineers recommended Mobil 1 accross the board. Yes, engine, tranny, and tcase. There was no way that I was going to try it in anything other than the engine though. I'll stick with products that have been proven through years of use.
...Sometimes, the more you see, the less you understand...
Redline MT-90 is the way to go. I changed the fluid in mine with Valvoline Syn-power full synthetic 75w90 then got to reading on this forum that a GL-5 lubricant is not the way to go in the AX5-AX15 transmissions. I sent a note to Valvoline regarding transmission usage and they replied that the additives they use will not attack the yellow metals (syncros). I dumped it anyway and put in the MT-90. The transmission is not near as notchy, although when cold, it feels like there is a hook on the gears between 1-2 and 2-3. If you care to double clutch, it is very smooth. My Jeep shows 135,000+ on the clock, so I'm sure there is plenty of wear in the transmission.
Back to the OP, I went to the DC dealer to get the "special" AX transmission fluid. I had a DC part number that I picked up off the web. The parts guy said the number had changed to a new number. He looked up the cross reference and eventually came back to the parts counter with a quart of DC 10w30 motor oil. I opted to change it to the Valvoline Syn-power 75w90, then dumped that for the Redline.
1997 Red Wrangler 4.0L - 5 speed - soft top w/full frame doors - 2 inch spring spacers and 1 inch body lift - 31 x 10.50 BFG on 15 x 8 Pro Comp 8069 rims
Thanks. I'm going to drain the 10W-30 and fill er up with Redline MT90. Hopefully that will quiet the tranny down and help it shift smoother.
If you do live in Colorado, I would be inclined to use either Redline MTL or a mix of MTL and MT-90.
I've used straight MTL here in Phoenix and the 1-2 shift in cooler weather (we barely get to freezing a couple of days per year) disappears.....with MT-90, I still had some 1-2 issues but nothing like the factory lubricant caused. MTL is a bit lighter weight fluid.
Just a suggestion. You can't go wrong with either one, in my opinion.