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Discussion Starter · #1 · (Edited)
I have a 1996 9000 cs, 166000 miles. The car is in incredible shape. BUT.... At times and on acceleration, I feel a vibration through the steering wheel and acceleration stumble - like a judder, definitely a resistance to accelerating. I do notice this is likely at 1800 to 2100 rpm. In normal driving (here in the US), my speed is 30 - 45 mph. This is on top of the wheelhop issue that this car suffers through. I have theories: injectors, tranny, engine mounts/struts. The auto tranny is at that age, but i have been meticulous in maintenace eevry 30k and otherwise, I note no problems. I replaced the forward (pass side) mount - others could use help but not yet desperate.

I appreciate any ideas and instructions to check.

I did have an injector problem some time ago - very noticable vibration (wham-wham-wham), nearly undrivable about 35 mph - a push on the injector connector fixed that. The car drives too firm thanks to the bad choice of bilstein HD shocks and struts and this exaggerates every vibration.
 

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Discussion Starter · #5 · (Edited)
Sorry! I'm just an airplane mechanic - working on my car is something I do when I have to.

This may be part of the overall ride issue - I did have the drive axles replaced about 15k ago (boots were leaking) and ride was never as smooth as I remembered.

This is one intermittant - a vibe with a feel that the car is hestitating. so it may be two issues. DI is fairly new.
 

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If the driver bushings are sloppy you'll get vibration up through the column (and under the floor) upon heavy acceleration.

But unlike your description (intermittent and hesitating), the vibration due to loose drivers is constant. Once it starts, it remains, and feels like a steady "wobble" - until the load is eased.
 

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Axles do not include the drivers which are on each side of the transmission final drive case. If you did not renew the axles soon enough the insides of the tripoid type CV joint driver can wear. The inner end of each axle has three lobes (hence tripoid) with needle bearing bushings similar to a Hooke's joint. These bushings ride in three matching slots inside each driver. This, amazingly, gives constant (angular) velocity unlike the four lobe Hooke's joint version. The bushings also slide in and out along the grooves giving suspension plunge equivalent to variable length axles used in some older rwd IRS systems. The internal grooves would wear unevenly if contaminated giving a vibration as the suspension or steering is moved.
 

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......the insides of the tripoid type CV joint driver can wear. The inner end of each axle has three lobes (hence tripoid).....
Wow!
I've given up calling them tripoid because everybody else in the (my) world calls them tripods; they look at you funny when you use the correct term. Then you have to explain, then they look at you funny.....
 

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Sounds like you have at least one bad inner tripod bearing.

Is the vibration more pronounced upon acceleration, and especially trying to accelerate up inclines then goes away when you take your foot off the gas?

Jack up the front end of the car and check the condition of both boots on each axle (inner and outer) for holes/tears. Next jack up the front end of the car and try to move each axle shaft by wiggling them around. If you see excessive play when you move the axle, look at the end going into the transmission on the left side and the end going into the carrier bearing on the right side. If there is a lot of movement at the shaft end, you either have a bad tripod bearing, a worn companion flange or both.

I just had to replace the left CV axle in my own car due to this --- A torn inner boot caused contamination of the tripod bearing. This resulted in the needle bearings falling out of one of the tripod rollers and the grooves in the companion flange had worn spots in them.

Replaced the axle and companion flange and the vibration issue went away.
 

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Tripoid. With three extensions from a central axis. Probably a coined word by a manufacturer. Hypoid refers to the off centre pinion and crown gearset invented to lower the driveshaft. Tripoid is probably invented to describe the particular joint. The word is not in the OED.
 

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Discussion Starter · #12 ·
RE: Everything about the boots and axles look good. No excessive movement. I had checked this a few weeks ago.

RE: there is a shudder around 35 - 45 mph during normal acceleration, but it is not always there. There is a smaller vibration that feels more like wheel hop, but it is not speed dependent (as a side note, my front tires were pulling and I had them replaced under warranty. there was no change in this smaller vibe).

RE: as for the plugs, they were changed at 160k (now at 166k) and DI was replaced recently (records not here but about 1 yr ago, no more than 2 yrs)
 

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Have you checked the lower control arms for worn bushings, ball joints or loose bolts? Undertorqued lower control arm bolts are a chronic SAAB fault. This leads to random movement of the control arm producing some pretty weird effects.
 

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Discussion Starter · #14 ·
Suoeraero: Thanks - I have checked and my Indy has checked. Nothing looks extrordinary and there is no obvious looseness but certainly there is wear after 16 years and 166k. I will fix anything but do not want to do things at random.
 

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I actually had a cross threaded bolt on my 99 which torqued to correct spec only because it was cross threaded. It was actually loose. I'm not suggesting that is your issue but it may be worth properly retorquing those lower a arm and subframe bolts rather than just looking at them.
 

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Discussion Starter · #16 ·
vibration

OK, I got an independent confirm that (1) the vibration is real and (2) likely the inner drivers. The mechanic with Saab experience went over the car carefully. Everything looked pretty good but he noticed a slight play in both inner drivers.

His repair quote gives me pause - he says the inner drivers are labor intensive on the 9000 - twice the book estimate. The quote for parts was $800 plus 6-7 hours labor. Anyone with experience - reasonable? At that price, I might just live with it.
 

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Are we talking about the tripod section or the "companion Flange" ?
Or.....the male or female part ?
The old 99/900 people press and move the "cf" sleeve to compensate for wear, but , with the 9000s I know little.
I have easily removed the "tripod" from the shaft using an air hammer (remove the E clip and the vibrations do the rest...This was done in order to R & R & R a joint boot.....YES! I repaired the boot ...a small tear, lots of work, cleaner, and Silastic.
 

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I've got two extra sets for my track version 9k Aero, they come free with gearboxes.

Buy a blown Aero or 2.3 turbo box for as little as possible, drivers come with.

Never put them in, but can be done without removing the gearbox, aside from potentially playing with the shims can't see how it would take that long. Both axles can be off in 30 minutes tops by a pro. Sourch used parts, try a different mechanic to put them in.
 

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Discussion Starter · #19 ·
from what I understood, he was suggesting the companion flange - he talked about wear grooves and partly dismantling the transaxle housing to get to a retaining clip, which increased labor time. The tripod is part of the axle replacement, which was replaced a couple years ago and is not an involved fix.
 

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Just noticed I think you have a 1993 2.0 turbo, if so do some parts numbers checks, determine which gearbox will yield the correct inner driver for you, you need the easier to find smaller ones, but check if the GM boxes (longblock engines) use the same driver as the FM gearboxes (1994a and later).
 
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