1979-1993 & 94 Conv [Subscribe to Daily Digest] |
GregD,
First of all let me say that I really appreciate your advice, amd what you suggest makes sense. At the same time, as you can tell, I am new to transmissions in general, but I am trying to understand why it is that the Sabb 900 transmissions like to grind downshifting into second when cold.
If I understand correctly, when shifting you move the synchromesh sleeve over the brass synchro. Since the synchro and sleeve are conical, as the sleeve engages the synchro, friction causes the gear to come up to pinion shaft speed. Thus when the gear and sleeve engage, there should be little to no relative rotational velocity. So if grinding occurs there must be relative rotational movement, and I can see a couple of reasons for this. One is that the syncro OD, and/or sleeve ID is worn or distorted so not enough friction is generated before the gear meets the sleeve. The second is that the spring that applies the axial load to the syncro is weak/worn out so there is not enough resistance and the synchro is pushed out of the way, again not producing enough friction. So why does this problem go away in a warmed up tranny? I can only guess that it has something to do with the relative thermal expansion of the synchro/sleeve or some property of the tranny oil. Since my second gear synchro doesn't look worn (coating still intact) I am apt to blame the spring or the sleeve, (or even the design :-) ) I figure I can try switching the sleeves around as you suggest and try some new springs. Even if I am grasping at straws shelling out for a spring or two certainly won't break the bank! BTW my pinion bearings didn't fail. I had the engine out for timing chain/chain guide replacement and figured I'd try to solve the grinding while downshifting into second problem at the same time...
Thanks again,
Jeff
posted by 64.229.157...
, Mon, 12 May 2003 09:05:40
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
