sprintman Posted September 16, 2003 Share Posted September 16, 2003 Mine 'ground' until I changed to RL75W90NS. Only had 65,000kms on it mainly highway which might have something to do with it. Maybe older g'boxes are less tolerant of a better quality oil? Quote Link to comment Share on other sites More sharing options...
frag Posted September 17, 2003 Share Posted September 17, 2003 I use Canadian Tire's regular semi synth in my gear box (just a tad more expensive than dino) and have no grinding problem. I dont «race» though. Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 17, 2003 Share Posted September 17, 2003 So I drive my soobie around for 10-15 minutes to warm up the diff oil...of course the MT/front diff will be warming up. But will the rear diff oil also be warming up if I am not driving in 4WD? I guess I do not quite yet understand how/what a diff really does, maybe someone could educate me. I don't have any dirt roads nearby enough to drive with 4WD. This is on the car listed in my sig line... vvvvvvvvvvvv Quote Link to comment Share on other sites More sharing options...
frag Posted September 17, 2003 Share Posted September 17, 2003 4WD or not the rear diff's planetary gears are always turning and meshing (the wheels are still spinning at a different rate when you make a turn) but are not under load when not on 4WD. I would suspect they still will be warming up but maybe not as fast. I would also think the front diff will warm up faster cause (1) it's always under load, and (2) it gets some heat from it's proximity with the engine. Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 17, 2003 Share Posted September 17, 2003 Hey Frag, Thanks for the input, you even answered some questions I didn't even ask! It all makes more sense now. Quote Link to comment Share on other sites More sharing options...
Setright Posted September 18, 2003 Share Posted September 18, 2003 I am in the process of ordering Redline oil for my gearbox, rest assured I will report back in a week or two when I have formed an opinion Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 18, 2003 Share Posted September 18, 2003 75W90NS g'box and do diif with 75W90. (not NS) Quote Link to comment Share on other sites More sharing options...
Setright Posted September 19, 2003 Share Posted September 19, 2003 Well, not sure I am going for NS in the gearbox. Cobb Tuning recommends MT90 for increasing shift speed, so I if Redline UK has it, I am trying it. Recently, replaced the diff oil, with Mobil synthetic, so that's staying in Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 19, 2003 Share Posted September 19, 2003 Trans requires GL5, MT90 is GL4, a big difference. Cobb Tuning shows 75W90NS and a picture of the bottle in oil section for Outback, WRX, Forester, Legacy. Better re-check me thinks. MT90 could be 'crunchy time' unless you are racing. Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 19, 2003 Share Posted September 19, 2003 Originally posted by subyluvr2212 So, after a few suggestions, I put regular Castrol dino in and I have not ground a gear since no matter how fast I shift. Castrol "dino"? Ya mean non-synthetic Castrol 80W90, or something else? Sorry that I don't understand the vocab... Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 19, 2003 Share Posted September 19, 2003 dino= dead dinosaurs=non-synthetic. But then lets complicate it with Castrol and it's Group III 'synthetic' eg. Syntec which is hydrocracked from dino but they rip you off selling it at the same prices as real synthetics, eg Mobil 1, Amsoil, Redline etc. Any wonder Castrol are not well regarded by a lot of 'oil aware' people? Quote Link to comment Share on other sites More sharing options...
Setright Posted September 19, 2003 Share Posted September 19, 2003 Hear you on the GL4 thing, Sprintman. I checked my car's handbook: GL5. Still, the Cobb page makes no distinction... Reckon I will play it safe and go for NS - I hope it kicks Mobil's rump roast, or it won't have been worth it! Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 20, 2003 Share Posted September 20, 2003 If g'box old and worn synchro's maybe 75W90NS too good. Excellent in mine and brilliant when say -6C. Very expensive here too. Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 22, 2003 Share Posted September 22, 2003 I'm having a hard time finding NON-synthetic 75W90 Castrol with the pour nozzle in Seattle. I find many different weights and of course lots of synthetic versions. I want to replace the rear diff and MT diff oil. I've looked at Napa and Shucks so far. I know I've seen, I thought it was Shucks, but they don't have it or any 75W90. Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 23, 2003 Share Posted September 23, 2003 Why do you want dino in your diff and trans? Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 23, 2003 Share Posted September 23, 2003 Because of what Subyluvr said. I'm not real hip at forking out $50 for some redline (replacing both front/rear diffs) just to find out he's right and grinding gears. It seems there's a bit of controversy over the matter, but I'd simply be happy with the less expensive side. Quote Link to comment Share on other sites More sharing options...
Setright Posted September 23, 2003 Share Posted September 23, 2003 Pianodirt! Wait a couple of days and I will be able to tell you how Redline performs....I ordered Friday and they promised me by the "end of next week" I would have it here.... Quote Link to comment Share on other sites More sharing options...
pianodirt Posted September 23, 2003 Share Posted September 23, 2003 Setright...I'll be waiting for your report! What if I put dino in the manual transaxle/front diff and redline in the rear diff, would that be a good combo? Subyluvr's comments make sense, needing the added friction of a non-synth oil for manual transmissions, since it is a human shifting and releasing the clutch. Humans can repeat the same consistency of timing/movement/shifting/clutch as an auto tranny can. Or maybe Subyluvr's tranny or clutch is worn differently than others, I dunno. But he did say he made a brouhaha about this on another board and finally folks were agreeing with him. You guys know more about cars than I do (i'm learning, got good and greasy and spilled gas everywhere yesterday:D ) and that's why I'm here. "How to keep your Subaru alive" has taught me a lot, especially how a car works period. Before I read it, I didn't even know what a valve or crankshaft was. Quote Link to comment Share on other sites More sharing options...
Setright Posted September 23, 2003 Share Posted September 23, 2003 Pianodirt : Dino oil won't necessarily have a higher friction co-effiencient. The main disadvantage with mineral oil (my word for dino) is a tendency to break down under heat "loads". This will reduce the strength of the oil film and allow metal to contact metal directly instead of being cushioned by the oil. It also tends to leave broken down components behind in the form of "sludge". By the way, synthetic oil is usually based on mineral oil components that have been "evaporated" off the base and re-assembled in a structure that suits the application. Anyway, this allows vastly superior stability under high temperatures and improves the film strength, even in relation to brand new mineral oil. THAT is why synthetics can offer better protection, it is nothing to do with friction co-efficient. The lower amount of friction has advantages in terms of fuel economy. Still, it pays to remember that a large portion of this friction is inside the oil, between the molecules moving within the film, not between metal components. I run only synthetics in my car, and I have no ill effects. Engine, transmission, and brakes have all been on syns for the last 60k miles since I bought the car, and I have no complaints. Nearing the 200k mile mark. Mobil syn in the transmission saves pennies on the fuel bill, but slows shifts, and that is the only reason I am going to try Redline. I don't get any crunching because I run a synthetic. No argument on the synchroniser cones needing a certain amount of friction to work properly. However, crunching is usually a product of the driver releasing the clutch too early, like before the gear has been selected fully. If you keep the clutch down, the gearstick won't move into the slot until the input and output have reached the same speed. Granted they will crunch if you really RAM the stick, but if you do that...well....you need to rethink your shifting technique and maybe practice a little double-de-clutching. I can shift my car from 4th to 2nd at 40mph and not loose speed. Passengers can HEAR it happen, but can't feel it: Clutch down Select Neutral Clutch up Rev it to 4000 Clutch down Select 2nd Throttle again to match revs as you move the clutch up:brow: The rear diff isn't LSD so a low friction oil will be just the ticket. Enough of my post, I will get back to you...... Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 24, 2003 Share Posted September 24, 2003 Exactly. I can go 5th to 2md double de clutching and maintain same speed in OB and older Mazda turbo I use as a fuel/lube/additive/grease test vehicle. Took much practice but just comes naturally now. Stops crunching even in Mazda that has shot synchro's Quote Link to comment Share on other sites More sharing options...
DerFahrer Posted September 24, 2003 Share Posted September 24, 2003 Okay, to further aid my discussion, I changed the old gear oil out of my XT on Saturday. I put my trusty Castrol 80W90 dino oil in, and it shifts better than whatever came out... Mark another one up for Castrol... Setright, I do know how to drive a manual correctly. When I had the Redline in the tranny, I would wait 3 seconds before shifting into 4th from 3rd at 4000 rpm. Otherwise, it would simply grind. I even double-clutched and it would grind a little. Going from 5th to 4th was a big no-no... The GL4 would NOT make you grind gears, you could slam them as hard as you want!!! I think Subaru built some controversial trannies in this time period. The synchros seem to be happier with the properties of GL4, but I would imagine that the gear-meshing action needs GL5. Remember, I said at one point, I mixed half MT90 half 75W90NS in the tranny, half GL4 half GL5. That largely fixed it. But an axle seal leak developed in my Legacy and one night it leaked a whole quart of oil on the driveway! So I poured whatever oil I had around in it, until I had the dealer fix it (front axle seals are not a home mechanic's best friend!!) They poured whatever they use in there to make up for the loss. So I had some 5 different types of gear oil in my tranny at one time! Feeling guilty and taking someone else's suggestion of dino, I put the Castrol in and have been happy ever since... Of course, other factors determine which oil is best. I don't slam my tranny into gear, heck, I pretty much don't run my cars hard at all... Also, it gets much hotter here in FL than where many of you are, and as we know, the hotter oil gets, the thinner it gets... I can, however, recommend synthetic, Redline especially, in a diff. That has no synchros, so it can only benefit from the special properties of synthetic. I did put Redline 75W90 (no NS) in my XT's diff Saturday too... But even after this novel is finished :brolleye: I still stand by my premise though that dino is the all-around best oil for Subaru trannies... I don't even think brand really matters that much. If you race, synthetic might be the best because of the breakdown of dino Setright mentioned. But if I were to really race seriously, I'd probly have a dogbox anyway:brow: Quote Link to comment Share on other sites More sharing options...
Setright Posted September 24, 2003 Share Posted September 24, 2003 Subyluvr, I wasn't trying to insult your driving skills! Just trying to make sure we are talking about the same thing, yes? Enough of the apologies: CobbTuning recommends MT90, but the Redline tech guy I spoke to in England suggested that I stay with a GL5 oil. Apparently, his local Sube dealer uses NS for all their servicing. Okay, he could be feeding me a line, but the oil is on the way, and I look forward to trying it. Believe you me, if it sucks I won't shy away from admitting it. This is an experiment, after all If it can speed up my shifts, and do away with the old Sube trait of clonking on the upshift from 2nd to 3rd, well, I will be pleased! Quote Link to comment Share on other sites More sharing options...
NOMAD327 Posted September 24, 2003 Share Posted September 24, 2003 Originally posted by brus brother The question remains, is it necessary to use gray Permatex on the plugs as one suggested. The rear differential plugs are standard pipe thread and have a taper that makes them tighten as they are driven into place. Without the taper, they would just keep threading in until they were inside the housing. This type of thread will seal almost 100% if no sealant is used, and will normally not jam where it cannot be removed in an application like this where there is oil on the threads. The purpose of pipe thread sealant is to seal the threads 100% keep the threads from jamming, and keep the threads from coming loose on their own. I never sealed any differential plugs before, but it sounds like a good idea. Quote Link to comment Share on other sites More sharing options...
Snowman Posted September 24, 2003 Share Posted September 24, 2003 If anybody cares, I changed the manually tranny and rear diff oil in my subaru about five thousand miles ago, switching from standard 80w90 dino oil to Quaker State full synthetic 75w90. After a very short time, the tranny started shifting much more smoothly. Previously, it would sometimes require a special touch to get it to shift smoothly from 1st to 2nd, or to downshift at any speed. Now it's incredibly smooth and easy to shift, and I can even downshift two gears at a time without any complaints from the tranny. It's also comforting that even after 5,000 hard miles, I can barely see the oil on the dipstick because it's so clear and clean, whereas the previous oil was quite dark. I have also been running Mobil 1 synthetic motor oil for the last 20,000 miles, and I am a firm believer in synthetic lubricants now. Another trick for getting the diff plugs out is to use a jack to put pressure on the wrench. Mine would not come out with normal methods, and that loosened 'em up fast. Quote Link to comment Share on other sites More sharing options...
sprintman Posted September 25, 2003 Share Posted September 25, 2003 Just dont put NS in your diff, its for transaxle only. The 2 to 3 shift with NS in my trans is like a hot knife through butter. Quote Link to comment Share on other sites More sharing options...
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