From: andyc@hplsla.hp.com (Andy Cassino)
Newsgroups: rec.autos.tech
Subject: Re: grinding gears when revving engine at high speed
Date: 31 Jul 92 01:21:47 GMT
Organization: HP Lake Stevens, WA

/ tr@samadams.princeton.edu (Tom Reingold) writes:

| In some situations, I want to accelerate quickly from a standstill to
| merge onto a high-traffic, high-speed road.  My Saab 9000S has a
| normally aspirated 2.0 liter 16 valve engine.  The car weighs about
| 3000 pounds, so acceleration isn't that good.  With this, combined
| with a very low first gear, quick acceleration doesn't come without
| some effort.
| 
| When I rev the engine to nearly redline, shifting to second gear is
| very tricky.  I try to pull the shifter into second, and instead of
| going in, it gives resistance and the transmission makes a very loud
| grinding sound.  What causes this?  More importantly, what is the
| proper way to shift quickly in this situation?

Hi there, a friend just called my attention to this posting and I'd like to
throw in few words on my experience with this problem.

I have a 1988 normally-aspirated 900S with manual transmission which I 
purchased new. The transmission has always been balky in just the manner 
you describe. In fact, sometimes it seemed that even at moderate RPMs the
first to second upshift could not be accomplished without some grinding.
Finally, I tried RedLine MTL at 75K and it helped a little bit, but the
problem basically remained.

At 87K miles the pinion bearings went and I had the gearbox rebuilt. There
was considerable gear chipping on first gear (which I do not recall ever
grinding) and second was quite bad. Third and fourth looked like new. The
pinion bearings were a mess, all the bearing surfaces were severely damaged
and there were signs of external debris impinging on the outer edges of the
race. It looks like the nice hardened steel gear chips created by grinding
gears were the culprits in this damage. The surprising thing is that the 
synchros themselves were in very good shape, it makes one wonder if this 
gearbox design is not rather deficient.

Well, I now have 107K and the new gearbox shifts much more nicely from 1st to
2nd than the original ever did, though I also have grown very conservative and
make all shifts quite more slowly and deliberately than before. (A nasty shop
bill has a way of doing that).

Anyway, I know the 9000 has different transmission, but perhaps a similar
design idiosyncracy in this regard. That is disappointing. I would advise 
avoiding any shifting that causes grinding, obviously it will catch up with 
your wallet in the long run (it did with me)!

A few weeks ago I had an opportunity to put a few hundred miles on a '92
9000S with the 4-speed automatic (and the 2.3L engine, normally-aspirated).
It is quite slow off the line (miserable, in fact, with the A/C on), but 
once under way, the transmission/engine combination is pretty nice. But
expect only 20-21 mpg overall, maybe 26-27 on the freeway.


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    % Andy Cassino                                       %
    % Hewlett-Packard - Lake Stevens Instrument Division %
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Newsgroups: rec.autos.tech