QBallz

So I finally got bored and decided to install SS brake and clutch lines. Total install time was about 4 hours mainly because I had never done it before, and brake fluid is VERY slippery and I kept dropping the damn wrentches, sockets, and pretty much everything else.

I also swapped out Diff and Trans with Mobile 1 75W-90, and flushed/filled the brake lines with Valvoline SynTech or something like that.

Well needless to say the SS lines where pretty much a waste because there is pretty much no difference in the feel of either the clutch or the brake. But it gave me something to do and was fairly fun because I had never worked on brakes before.

However much like others have said switching to a synthetic gear oil kicks major ***. Shifting is super smooth, and there is no notchyness when shifting.

Fanman

I actually felt the biggest difference from my SS brakelines. The brake pedal feel was much firmer, and the more secure. More solid feeling. When I changed out the pads there wasn't a big difference.

r0tor

iTrader: (1)

umm, last i check Mobil 1 75W-90 is a differential oil and doesn't have the correct GL rating for a manual tranny

QBallz

Owners Manuel says GL-4 or GL-5 75W-90, and Mobile 1 75W-90 said it meets or exceeds all GL-5 standards. I checked 3 or 4 times because I thought it was odd to use the same in both.

QBallz

Maybe I still have a bit of air in the lines then, because the pedal feels almost exactly the same. I didn't bleed the master cylinder because I kept resivour full the whole time.

I guess I can try bleeding that and seeing if it firms it up a bit more.

r0tor

iTrader: (1)

Manual tranny fluid is usually GL4 and differential fluid GL5 as the different applications tend to need different amounts of friction to perform to their best

QBallz

Either way, it's currently shifting super smooth, and there is no grinding or trouble changing gears. I'll probably switch to a GL-4 in a year or so as long as I don't run into any trouble with whats currently in there.

QBallz

I've picked up an odd rattle in the transmission. For example if I am in first and I depress the clutch while at a roll is here a rattling sound, could this be to the Tranny fluid, it could have been there before but the transmission used to be so damn loud I may not have noticed it.

bureau13

I am not familiar with the Mobile oil in question since I've never used it, however some oils may be used in both...Royal Purple Maxgear, for example, is designed to work in both diff and tranny...I ran it in my RX-7 for years with no problems, I just haven't bothered to put it in the 8 yet (lazy I guess).

jds

Red Devil

^^^
I've got Royal Purple 75w90 Max Gear in both my 8's manual transmission and differential. Had it in there for 10K now with no issues.

skillmaker

QBallz,

How is the Mobil1 holding up for you now? Still OK? Any problems or issues?

Wanna know because I am ready to switch over. Just looking for feedback.

Lots of folks seem to use redline and others. I trust Mobil 1 a little more, but you are the only one I have seen so far use the same product in both tranny and diff.

Please let me know how it's working?

Thanks in advance!

yiksing

My manual says GL-5 is compatible in the tranny and my dealer said ok as well since their normal replacement fluid would be a mineral SHELL Spirax 90. I also used the Mobil 1 Mobilube SHC 75W-90 (this is discontinued). Anyway after the change I find that I have to completely stop in order to shift into first gear (used to be able to shift into first at 5 km/h speed) but everything else is smoother, it sorts of feels like you don't have to overcome the tranny fluid viscosity to shift the lever so I can shift faster now. Overall I said its totally safe.

QBallz

I had some nasty gear whine, and a slight rattle. I swapped out out with Redline MT-90. Shifting is smoother and the noise has back to normal. Mobile 1 was noticably better than the OEM crap, but Redline is the best.

I still have Mobile 1 in the diff and havnt had any troubles with it.

Winning 8

MT 90 is da bomb

yiksing

You guys are lucky to get RP and Redline over there!

skillmaker

Changed both tranny and diff to Mobil 1

No leaks.

Shifts slightly smoother (no major difference, still works great)

Differential works fine. Made it through an autocross and a couple hundred miles without any issues.

Gained 2-3MPG it seems.

Noise from tranny and diff seems exactly the same as stock lube

nycgps

iTrader: (1)

It seems that Qballz was the first one that has tried the Mobil 1 (Skillmaker is the second :P) but QBallz already swap it out of his 8's tranny with redline.

Well, Im looking to change my Tranny and Diff. fluid .... Mobil1 75w-90 is easy for me to get. I had Royal Purple before and I love its performance, but sometimes I dont really like the idea that I have to order it everytime when I need it.

So .... if mobil 1 is ok for tranny or not ???

skillmaker

750 miles later, two autocrosses.

No significant differences encountered. Still shifts smooth. Still minimal noise. No drips. No problems encountered.

Tranny does seem to produce less heat now.

No noises from differential. DSC, limited slip, and traction control all function as before.

So far, so good.