I put some Redline MT90 in my Nissan, now on the 1-2 shift.....

[Fastzntn]

I have a 1991 Nissan 240SX w/ a five speed. The car is in surprisingly good shape for it's age, and I'm big on keeping up with the maintenaince on my vehicles. I wasn't experiencing any problems with shifting/grinding/clunking or anything, but decided since I recently bought the car and did not have any fluid change documentation that I should change out the fluid in the rear end and trans. I had some people suggest Royal Purple, some suggested Redline, and a few more suggested Mobil 1. The manual specifies 75w90 GL-4 rated gear lube. After doing some research I decided on Redline MT90 in the trans, and Redline 75w90 gear lube in the rear end. This just started after the fluid change: When the car is cold it will crunch on the 1-2 shift. Not a grinding sound, but a crunch that I can feel in the shifter slightly. This only happens for the first 5 minutes or so of driving, and then after that first period of time the 1-2 shift is fine, not even noticeably notchy. The other shifts are good, no crunching or notchy feeling. Also if I leave the shifter in neutral for an extra couple of seconds before putting it into second there is no crunch. Is this normal? Is this something that I need to worry about as in get that MT90 out ASAP? 192,000 miles on trans/rear end.......

 

[Rebel Rouser]

If you do a search on Redline MT-90 here, I believe you'll find one of the more notable posters here(can't remember their handle off hand)recommends a 50/50 mix of Redline MTL/MT-90 in manual transmissions calling for a 75W-90 for the exact issue you describe, cold shiftability. I currently have the straight MT-90 in my NV4500 light truck transmission, but plan on using the mix at the next fluid change interval. No real issues, but would like easier cold shifting. The GL-4 Redline products are good stuff.

 

[Fastzntn]

Thanks for the tip. I'll see if I can dig up some of the old posts.

 

[unDummy]

If the problem only started with the new fluid, get rid of it. Give the Royal Purple a try. Also, bleed/adjust your clutch if possible. And, inspect/lube the shifter/shift linkage. I've used MT-90 in multiple Nissan transmissions and recommend it to everyone needing a GL4 90wt oil. But, some trannies don't like it. No two trannies are identical and some are fluid picky.

 

[Leo]

I have a Nissan 240SX with the SR20DET motor (std issue here in Australia). Presumably it uses the same 5 speed as you guys. Some people on our local forums say MT90 isnt all that great for our transmissions. I havent tried it yet in my trans. However I reckon it would be good to drain half of the oil and replace it with MTL as others suggested. Let us know how it goes!

 

[theguru]

I have the Nissan 200sx with the 6 speed and changed to the MT90. 1-2 is definately better than standard fluid. I may however do the 50/50 mix with MTL next time. The oil was changed at 2,000km, so the original oil was not worn out.