bulwnkl

Never knew Rislone was used as a transmission cleaner/flush. Something that will work for this (cleaning SAFELY) is Auto-RX. See auto-rx.com for details. Another thing that has helped my XT-6 5-speed tremendously is a transmission fluid called MTL-R from Specialty Formulations. It's unbelievably good stuff.

I like that! So am I...

Auto-RX?

No, a transfer case is something you'll see on a pickup(or many SUVs, etc.). It is a separate housing/unit bolted to the back of the transmission. The driveshaft for the rear axle comes straight through it, and going forward from the "side" of it is the driveshaft that goes to the front axle. A Subaru houses all the mechanism that accomplishes the same task within the transmission. It also works in an entirely different way compared with a transfer case. A Subaru 5-speed actually has a differential in the "center" of the drivetrain. A 'classic' pickup-type transfer case has no differential-type mechanism in it. It is a simple dirveshaft straight through to the rear and then a chain or gearset driving the shaft that goes forward. Some of them you can engage or disengage the drive to the front axle, others you can't. If you had an automatic tranny in your Outback, then you would have a mechanism that could possibly be called a transfer case, but not in the sense of the pickup-style mechanism described above at all. To me it would be too big a stretch to call the Subaru AT mechanism a transfer case. HTH

Yes, I suppose you are right. OTOH, my older Subaru (XT-6) doesn't have this problem. Imprezas at least certainly do, though. It appears to me that Subaru has altered the synchros over time to try to address shift quality somewhat while dealing with both increasing power/torque levels of newer engine series and also the GL-5 rated oil that their hypoid transaxles require. I am aware that a fluid can be multi-rated. IOW, it can be a GL-4 and a GL-5 at the same time. This is essentially because the GL-5 rating requires more of the same thing that GL-4 requires. In point of fact, the Extreme Pressure/Anti-Wear (EP/AW) additive in GL-4 and GL-5 lubes from most oil companies is exactly the same thing. Here is some info from the lead blender/chemist for a West Coast oil company: "GL-4 vs GL-5 other than vis grade is only the difference in amount of AW/EP additive put into the oil. Most oil companies will use 1 additive package for both Gl-4 and Gl-5 the difference is a GL-4 will take a treat of 2%wt and a GL-5 will be a treat of 7%. same additive just more..." You see, the lower additive rate of a GL-4-only fluid is simply insufficient for good durability under the extremely high sliding forces seen in a hypoid differential. Remember that not all hypoid gears are in differentials. Please don't misunderstand me; I fully appreciate and respect anyone's prerogative to choose what fluid they use in any given application. I also think it is important to understand the implications of such decisions. I asked the wrong person above, so I'll ask you, Setright: How many miles have you put on any one Subaru transmission following the installation of a GL-4-only (not multi-rated to include GL-5) fluid?

Oh, I misread/misunderstood. My mistake; sorry.

I too will differ with you. GL-4 is not at all suitable for heavily loaded automotive hypoid units. It may be suited for lightly loaded hypoid units. Subaru didn't choose GL-5 as a required specification out of the air. Here is some information I pass along from the RedLine tech department: "GL-4 Denotes lubricants intended for axles with spiral bevel gears operating under moderate to severe conditions of speed and load or axles with hypoid gears operating under moderate speeds and loads. GL-5 Denotes lubricants intended for gears, particularly hypoid gears, in axles operating under various combinations of high speed shock loads and low speed, high torque conditions." Please show me some 'heavily loaded' automotive hypoid differentials which do NOT specify or recommend a GL-5 rating. No cherry picking back before the GL-5 spec was created.

The thing about GL-5 gear oil is that it's nearly all built with rear-ends and unsynchronized transmissions (like in semi-trucks) in mind, but NOT with synchronized transmissions (like in a Subaru) in mind. The thing with GL-4 gear oils like RedLine MT-90 or Castrol Syntorq, or Syntrax or whatever it is, is that they do not provide the protection necessary for hypoid gears. What are hypoid gears? There's a set of them in your transmission called the front differential. Not all differentials are hypoid, but all Subie fronts are. So, do you want the protection your gears need, or do you want good shifting? The best widely-available compromise seems to be a dino GL-5 gear oil. They don't shift terrific, but they seem to be better than most of the synthetic GL-5s. The only fluids I know of that meet the required GL-5 spec and are built for synchronized transmissions are RedLine 75W90NS and Specialty Formulations' MTL-R. As you've likely read on here and elsewhere, the 75W90NS is usually liked, but many times not. Everyone I know of who has used the Specialty Formulations product likes it better than anything else they've tried. I have RedLine in now, but not the NS. It actually works reasonably well for me, but I don't shift fast and I have an older XT-6. I'm buying some of the MTL-R this week, so if you can wait a couple/few weeks, I'll have some experience with the SF product as well. It's a full-synthetic (PAO/Ester combo) that's specifically built for excellent shifting, but it also meets the GL-5 protection requirements of your front diff. rweddy, how many miles have you put on any one transmission after putting in MT-90 or the Castrol product?

Since there isn't a transfer case, I don't think it's that. Our '99 Outback had something very similar. A 'clunk' or almost a 'thump' at not-reliably-reproducible times. However, it became semi-reliable at doing it around a corner with a little bump in it. It sounded to me like something forward of the cab. In particular, I thought suspension or crossmembers. The dealer we bought it (used) from has a 'warranty' on all their used cars so we let them look at it. They said they didn't find anything but put a wrench on a bunch of stuff anyway to make sure all was tight. That more or less eliminated the problem, but we thought the car pulled slightly to one side. Took it to an alignment shop, that fixed the pull, but the thump/clunk was back. Took it back to the dealer who this time said they found something loose and tightened it. The service writer did not appear to me to know precisely what was loose, or else they really didn't want me to know what it was. That fixed it and we didn't have any more trouble with the car, but we only kept it about another 5-10,000 miles. SOooo, I'd look to front suspension, frame crossmembers, or similar things. Put a wrench on every nut or bolt there is and see what you find.

Hi, I'm pretty new to posting here, but I wanted to re-awaken this thread. Has anyone had wear problems from using the non-GL-5 MT-90 in their 5-speed? Has anyone tried Specialty Formulations' MTL-R? See http://www.specialtyformulations.com I'd really love to hear from anyone who has tried the SF product. 75W90 GL-5 but made specifically for transmissions. Anyone?

Are you a VideoLan man? Or Ogre?