1999 Saab9-3 slight wobble on acceleration


#1

Well I got the Saab and everything is actually pretty good, all features work no damage or rust, might be a small external oil leak but it’s hard to tell without checking it over time.



The only thing that has me concerned is a slight but definitely noticeable wobble when accelerating. I’ll be putting it up on ramps today to give it a closer look so any ideas what could be causing this or what I should look for? We never got it up over 40mph on the way home so I don’t know if it gets worse or better at high speeds.



Again, thanks for any pointers.



126K, 2.0


#2

Also when shifting from reverse back into drive it stalls about 80% of the time. If I pause in neutral for a second it doesn’t. It starts right up again after.

I plugged in a code scanner and it showed no problems.

ok440 around?


#3

The first thing I would look at on the wobble would be tire balance. With front drive a tire imbalance can cause something like this.
I would then inspect the inner tie rods for looseness. Jack the front wheels up one at a time, grasp the tire at the 3 and the 9 o’clock position and try to detect any slop when you move the wheel back and forth. There should be none. If there is, the tie rods and the tie rod ends should be inspected to determine which is at fault. SAAB builds pretty good suspension stuff so worn tie rods would be an oddity. Tie rod ends would be more likely.

There’s also the possibility the wobble could be caused by an engine performance problem such as fuel delivery. A clogged fuel filter may allow the correct pressure but not the right volume. There is no code for this and I would think if it were something ignition related (plugs, wires, etc.) the CEL would be on and a code would be present.

My guess on the stalling is a dirty Idle Air Valve. These are usually pretty simple to remove and clean with aerosol carb cleaner.


#4

Many thanks ok440, I’m trying to get as much info as possible before bringing it in to my mech and this helps a bunch. I’m running across several mentions of an “inner driver” (inner CV joint that sounds like to me) or “tripod bearings” possibly causing this wobble due to uneven wear, is that an expensive repair, very labor intensive?

I will be checking the tie rods and wheels as you said tomorrow.


#5

If by “wobble”, you mean the nose of the car hunts from side to side, it could be wheel alignment…especially. toe alignment.


#6

It stays straight and the steering wheel doesn’t pull or anything. I took it out today and accelerated hard and the wobble feels like an up and down motion, the harder the acceleration the more pronounced the wobble. Based on that I think I’ve isolated the problem, inner CV joint (AKA tripod bearing, inner driver)

The inner drivers connect the transmission to the drive shafts. They can fail from lubrication issues or from wear and tear, the thrust surfaces can develop depressions inside the carrier above on the mating surfaces. A very small depression in the driver mating surface will cause a vibration problem under loads or acceleration as the tripod bearings rides in and out of the worn area.

The main thing I’m unclear on now is how extensive the repair is, does the tranny need to by disassembled to replace the tripod bearing? Other than that it seems this isn’t a safety issue and won’t cause other damage, it’s primarily a nuisance.


#7

Yes, a worn CV shaft can cause a wobble on acceleration. SAABs use a tripod joint on the inner end and a Rzeppa joint on the outer.
That being said, SAAB CV shafts usually last forever if the boots are not torn or split. The inner joints are especially reliable and CV boot failure is rare even. They use a very high quality rubber that holds up extremely well.

For what it’s worth I worked as a SAAB tech for a number of years and can probably count on one hand the number of CV shafts I’ve replaced; and those were usually due to things like wrecks, torn boots and being submerged in water, etc.
They’re just not much of a problem with SAAB at all.
The same goes for their engines and transmissions. In a word - bulletproof. Never had to do any trans work, only did one complete engine overhaul, and a few head gaskets. The latter was usually due to someone continuing to drive an overheating engine or in a few cases; someone tweaking the turbocharger to up the boost, which was followed by blowing the head gasket out and/or pulling head bolts loose.


#8

I should have added that the trans does not need to be disassembled for repairs on the CV shaft and tripod joint. It’s simply a matter of removing the axle nut, separating the tie rod end and ball joint from the steering knuckle, loosening the clamp on the inner boot and removing the shaft.
(Care must be used as it is possible for the outer rollers to fall off the shaft. This leads to needle bearings going all over the place and if one is lost…you will need a new shaft.)

I still suspect a tire or tie rod end though.


#9

Thanks again ok440, I will definitely be checking what you suggest before trying to get the CV shaft/tripod worked on. I wasn’t able to jack it up again yet (I hate those scissor jacks) but when I had it up previously the passenger side outer CV boot had a small patch near the tire that looked scraped up. Odd, I took a couple of pics of it.

The transmission stalling from reverse into drive seems all cleared up, it was low almost 2 quarts, seems fine now. The old fluid looked kind of dark so I’ll probably be getting that changed out once I get it on the road.


#10

While I have your attention ok, can you identify this? It’s a small aluminum cylinder near the air filter. It seems to have not been secured properly and through friction a wedge was carved right through it. It’s attached to a hose that connects to a lower area near the serpentine belt.

edit- I would normally just go out and buy a Haynes but the only manual I could find for the 9-3 I had to order from Canada on a CD…


#11

I would not worry too much a scuff on an axle boot if there is nothing apparently shaken loose and rubbing on it.
The part you’ve showin in the pic does not ring a bell right off the top of my head, but will think about it.
The trans fluid being 2 quarts low would concern. Reasons for this could be someone servicing the transmission and not adding the correct amount of fluid, an obvious external leak, or a not so obvious internal leak such as the transmission fluid cooler which is located in the engine cooling system.
You might inspect the engine coolant and note if it has an oily substance in it or if the coolant appears to be a sludge.

Another possibility on this wobble could be a faulty engine or transmission mount. With the engine idling shift into reverse or drive and note if the engine appears to have a significant amount of movement. It should not if the idle speed is correct.


#12

Thanks for your help ok440, I talked to my mech today and he has it now. I’ll post back when I find out what the deal is.


#13

Well the drivers side axle is the problem, it has a lot play in it near the tranny. Everything else seems to be in tip top shape. My mech isn’t all that familiar with the car though and said he wants me to have a tranny shop do the work. I’m thinking about bringing it to the closest Saab dealership just to be certain.

Again, thanks for all the help.


#14

Oh, about the ATF leak- I have yet to check the coolant for contamination but there is a fresh oily substance all around the lower passenger side area of the radiator. I checked the WIS and it looks like it’s coming from near the tran fluid cooler line.

I wish it would stop raining around here for a few hours so I could really get a better look at everything.