Date: 26 Nov 2002 20:03:52 -0800
From: (Lance Morgan)
Subject: Re: c900 harmonic droning?

SkodaPilot <> wrote in message news:<>... > In article <>, > says... > > > > I've heard it twice in 3rd, and consistently in 5th through whatever > > the 70 to + 85 mph corresponding RPM range is (I did jot down some RPM > > #s, but can't find them right now, from a high-speed tollway). But I > > haven't heard it in 4th (or any other gear), at similar RPM. > > > Just a thought, but in a Saab (looking to find one soon), how are 3rd > and 5th physically placed in the box in relation to 4th? > > Could it be wear on a particular pinion or bearing that is only loaded > when 3 or 5 gear is used, and is only susceptable to resonating when > spinning at a certain revs, or when loaded with a certain pressure? > > Seems odd that it should be 3 and 5, not 4, and not be transmission > related? I tried to evoke the noise in 4th gear today. It wasn't the best of road or wind conditions (not too bad, tho) - but I couldn't detect anything (it may have been masked - I'll retry under better conditions). I could sometimes hear mild noise in 3rd. Fairly noticeable in 5th, from about 68 mph (~2800 RPM) continuously to just touching 80 mph (~3400 RPM) [and presumably faster]. Noise was most pronounced when accelerating in 5th (and this noise is not terrible, but mildish+), and still there when letting my foot off the gas with the clutch engaged. The pinion gear failure is oft mentioned - usually referred to as a whine, upon accel/deceleration (but haven't read anymore detail than that). I wonder if what I'm hearing is an atypical pinion gear failure. There seems to be mixed views as to how much stronger the post 88 c900 gearbox is, wrt the enlarged pinion gear. Brief conversations w/two ASE Saab mechs: one detailed pinion gear _housing_ failure being more common than the pinion gear itself; and the other saying grinds into 5th gear (not sure if this was in ref to a syncho prob or what). This is speculative deduction on my part, but it seems like Amsoil is successfully used by some for pinion gear problems, and Redline MTL for synchro problems, with regular replacement recommended by some for the latter. I've had very successful first-hand experience in a VW GTI with Redline and a balky 2nd gear synchro (don't know how/if this may apply to a c900 transaxle) - a remarkable transformation I'm going to give one of the syn's a try (after being under the car a couple of times, now, I'm beginning to think the 2.1Ls are like some of the 9Ks, sans the 3/8" drive drain holes [IIRC, Townsend is drilling/tapping drain holes].

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