[troy1974]

Hi on my 2001 SE I’ve noticed since owning it for the last two months that when I start the car from cold I hear a kind of whining from the front end that’s in sync with the speed of the wheels - it happens whether I’m in gear or coasting in neutral and only happens when moving not stationary and in neutral revving the engine. The sound is similar to the sound of the reverse gear but quieter. Disappears when at operating temp. Any ideas ? Thanks

 

[Mimmi]

Change gearbox oil.

 

[troy1974]

It was changed 3 months ago

 

[Mimmi]

Oil is correct one and oil level is correct?

 

[qwikredline]

Wheel bearing?

 

[troy1974]

I’ll check what oil the previous Owner put in. Never heard a wheel bearing sound like this - more a whistling sound - like I said almost like how the gearbox sounds in reverse . Gears work fine by the way , very precise and smooth , no other noises or problems. And again as I said the noise goes away after the engine has warmed up

 

[jvanabra]

IME it's the diff. If it stops when coasting in neutral, that's pretty likely.

 

[EdT]

My experience with the manual FM transmissions is that they can make a whining gear noise, especially when cold. I assume it's the final drive gear, as it makes no difference which gear ratio it's in. On my NG900, it went on for years and tens of thousands of kilometres, so I assume it's pretty harmless--unless it's indicating a low gearbox lube level.

 

[BobSaabit]

Like Mimmi asked... what fluid?

 

[troy1974]

Ok just checked - it was changed by the previous owner at a workshop - the receipt says MT-90 and they used 2 quarts ? Sound right ?
thanks

 

[troy1974]

It was changed 12 months ago not 3 as previously mentioned - is there a dip stick for the gearbox on this model ?

 

[troy1974]

jvanabra it still does it costing in neutral

 

[Mimmi]

Wrong oil.

 

[troy1974]

Really ? What oil do you recommend ?

 

[jvanabra]

Ideally #93165290 but using that may require a multiple drain/refill operation as it should not be mixed with other fluids.

MT90 is probably fine... it's a GL4 75w90 gear oil, so shouldn't be an issue.

If the noise is present while coasting in neutral and changes with road speed, that does suggest wheel bearings. Does it change in sound depending on which side of the car is loaded?

 

[troy1974]

Ok thanks for the tips! I have had a lot of experience with wheel bearings and the sounds they make and this doesn’t sound or respond like they usually do when you apply load etc plus all the wheel bearings were done less than 12 months ago according to the service records I have , along with new brake discs, pads , new shocks . Plus usually wheel bearing noises I’ve heard before stick around after the car has warmed up.

The sound does sound like a gentle version of that high pitched reverse gear sound, the sound disappears after about 5-10 minutes of driving so does point to perhaps a fluid warming up. The car is actually up at my workshop at the moment so couldn’t check but as I understand it doesn’t have a dipstick level check for the manual gearbox right ?

 

[troy1974]

P.S I would love this to be a wheel bearing rather than a gearbox noise !

 

[jvanabra]

Correct, no dipstick, just a level plug... add fluid til it runs from the plug. It's a bit of a pain to access, but the only way.

 

[BobSaabit]

Here's the TSB on the fluid flush and fill: MTF0063 Conversion

Qwik does gearboxes all day long and I've read enough of his stories to only use the recommended fluid. It's not worth the risk.

Look here: saab 93165290 - Google Search
He also suggests this: Fluid - GM (19351859) | GMPartsDirect.com or 19351859 Manual Transmission Fluid (SAE 75W-85)

He often has an updated suggestion, so he might chime in with something newer.

 

[EdT]

It may be hard to get that GM part number in Sweden. But there should be plenty of these gearboxes and shops familiar with the best fluid.

If it has the right fluid, to the right level, and it makes some gear noise, I would ignore it. Both the FM transmissions I own/owned make some noise at low speeds, especially when cold. Hasn't caused any problems.