Originally Posted by RedPhoenix

I did today actually. Went from Mobil 1 to GM Synchromesh. Same issues above apply though.

Originally Posted by lemmiewink

Ok changed it to redline mt90! Feels like new again. Hope it works in the long term. will report back with findings.


Also. some posts from supramania while I was doin research on the subject.


"The cliff notes version is the R154 and W58 trannys NEED a certain amount of friction to work properly. RP Max-Gear is *too* slippery to provide this friction...RP Synchromax is even more so. It is more an ATF type lubricant and thins out significantly at higher temps. IMO, these 2 gear oils are not well suited for our manual trannys...the success many guys have seen using these oils is due to the slippery characteristics of these gear oils "freeing up" (reducing friction) parts in the R154/W58 that are on the way to failure. This is not fixing the problem...that sound from your tranny is the sound of inevitably.



The reason more modern trannys spec a gear oil like Synchromax (or GM's synchromesh) is to improve cold shifts. The thicker oils in a GL-4/5 category do not shift well at lower temps...they need to warm up. The problem is Synchromax does not have the extreme pressure protection, oil film thickness, and shear stability required...this will increase wear on the gears. Synchromax may help quiet down a worn R154/W58 for a while, but it is not really helping the problem...it's masking it.



uote:
With most lubricated components, the slipperier the better, but this is not so with manual transmissions. The synchronization of shifting gears requires friction to transfer energy from the synchronizer, which is locked to the input shaft, to its mating surface attached to the gear to be locked in as the drive gear. The drive gear is selected by using the shift forks to slide a synchronizer ring, which rotates at the same speed as the input shaft, in contact with the selected drive gear. Once the drive gear is brought to the same speed as the input shaft, the locking ring on the synchro assembly is allowed to slide over and lock into the drive gear. The time this process takes depends on how easily the synchro ring moves and the rate of frictional energy transfer between the two synchronizer surfaces. Higher viscosity lubricants slow the sliding of the synchro ring on the input shaft and require a longer time for the oil to be squeezed out from between the mating synchronizer surfaces. After the lubricant is squeezed out, the coefficient of friction of the lubricant determines the rate of frictional energy transfer between the two surfaces. Slippery lubricants such as hypoid gear oils (like RP Max-Gear) can take too long to synchronize the gears, which promotes synchronizer wear. Red Line MTL and MT-90 has a coefficient of friction which is greater than conventional oils, allowing a quicker transfer of frictional energy."

This is from a member named "jdub" who is a mod there and under his name is. Official SM Expert: Motor Oil, Lubricants & Filtration

Another quote commenting on why royal purple may "seem" to work at first. From the same person

"In any case, the point is Synchomax is much too thin for either tranny. Max-Gear will work, but the friction modifiers can cause problems with the syncros on a tight tranny. IMO, the improvements guys see using either RP product come from freeing up worn syncros...the tranny is on the way out and the frictions modifiers grant a reprieve. It's not a matter of if the tranny is going to fail, it's when. But if it works and puts it off for a while, it's a viable technique...I'd save up for a new tranny or a re-build though"

Originally Posted by lemmiewink

Hey, you might want to change your transmission oil to something other than gm synchro mesh.

I'll just quote myself in my other thread.




Anyways I didn't mean to jack the thread, but oil is important none the less.

Originally Posted by stockhatch

Without hearing it in person its tough to say, but I would say your mainshaft bearings are probably ok. Could be countershaft bearings, or as was mentioned before, it could be the input to mainshaft bearing.

With all that said, I still lean towards gear whine due to worn gears. Probably input to countershaft since that mesh point likely sees the most load over the trannys life, and that is the path of power flow for all gears except 4th.

Just have to crack it open and see, or let it fail and then try to determine what tore through what first.

Originally Posted by Ali SC3

Mine still makes the same noise, Redphoenix any updates?

I had read somewhere about it possibly having to do something with input shaft wear, but the w58 is such an overlooked tranny I dont think anyone is going to take the time to tear it down just for a whirring noise. probably just live with till upgrade time.