[0341_Jarhead]

Hello,

I'm having a few issues with my '99 Outback. One is that when I get the car up to speed (35+ M.P.H.), I can hear gear noise (just operational whining, not grinding) coming from the tranny or transfer case. I recently replaced the duty "C" solenoid, rear clutch plates and friction discs, and the spring that goes underneath the pressure plate which actuates that clutch pack. I also had to replace the transmission mount, which accounted for most of the clunking and grinding noises. The whining decreased after these repairs, but it's still pretty audible. I'm guessing that something is engaged all the time that normally shouldn't be. I had a '97 that didn't whine like this while at speed. That wagon had a standard transmission, though.

The front wheels also still skip a bit when I turn slowly on a hard surface. Not nearly as badly as before I changed the "C" solenoid, since now only two wheels skip. Could one of the differentials (front or center) be locked?

The car also shifts rather abruptly, i.e. it's not always a smooth transition from gear to gear. When the vehicle is cold, it takes until about 4,000 RPM until the transmission shifts into third gear. Also, when I'm descending a hill, sometimes when I apply the brakes - even just a tap of the pedal will do this - the transmission down shifts into third. I can usually force it to up shift again if I move the selector to third and return it to drive.

As you can see, I'm not terribly familiar with the transmission or transfer case of these cars. Could the "violent" shifts be a culprit of the transfer case issue, since the engine is under a heavier load?

I also changed the transmission fluid and filter when performing these repairs, and they existed before the repairs.

Any ideas? Thanks in advance!!

 

[1 Lucky Texan]

was the previous trans filter the original stock spin-on? is the replacement OEM?

does the 'skipping' go away if you use the FWD fuse?

 

[0341_Jarhead]

The original filter was an aftermarket brand; I forget which. Yes, I replaced that one with a Subaru filter, which was outrageously expensive.

By using the FWD fuse, do you mean to remove it? I haven't tried that, no. I'll give that a shot this afternoon.

Thank you

 

[1 Lucky Texan]

on your car, I believe you insert a spare fuse (any size)

look in your manual about emergency spare use. should be a fuse slot in the box under-hood.

any sign that the trans pan is dented?

 

[0341_Jarhead]

Now I understand. I think I've heard of that trick.

No, the transmission pan is intact. If anything happened to the valve body, it may be clogged with dirt or something.

 

[0341_Jarhead]

Ok, I put the FWD fuse in, and the "FWD" light came on in the instrument cluster. There was no change to the symptoms: still some slight binding while turning on hard surfaces at a slow speed, still the excessive gear noise while traveling at speed. Unless closing the circuit to remove the rear wheel drive from the equation did not work - which I doubt - my money is still on the front differential being locked. What do you think?

 

[1 Lucky Texan]

is the car new to you or did these symptoms just appear? There is a magnet on the front diff's plug - look for 'chunks' or excessive 'sludge' on it. (1/4 or so teaspoon 'might' be OK, and no pieces we hope) Front diff needs GL-5 gear oil.

2-3 little possibilities still exist ; sometimes a carrier bearing or a u-joint can somewhat mimic binding, not common but have read of it a coupla times. I suppose the carrier bearing might make the noise you hear...hope others with more experience can comment.

even if the Duty C Solenoid is working as intended, the clutch plates in the tail shaft can bind/catch and won't fully release the rear drive shaft. Did the 'basket' the plates go into have smooth grooves?

but, front diff, rear diff - they're both in the trans - so, you might do well by swapping in a compatible trans from a wreck. may even have fewer miles than yours. car-part.com or LKQ might be good places to start. Just try to eliminate any other possibility like the driveshaft and it's parts, or a swapped rear diff with wrong final drive.

 

[0341_Jarhead]

The whine existed when I bought the car, but I've only driven it for maybe six or seven months. The front differential is something I have yet to check. It wouldn't surprise me if either the oil level is low, and that fried a bearing, or an axle got shoved into the differential when the car was it on the front passenger side (I bought it as an "R" title) and beat on a carrier bearing.

The universal joints were in good shape; I checked them when I was replacing the duty "C" solenoid. The clutch basket was in good shape. I know the grooves you're talking about, as I've seen them several times on dirt bikes and four wheelers which also use a wet, multi-plate clutch. None were present.

The front differential is external to the automatic transmission. The standard transmission had the front and center differentials integral to the transaxle. I had the tail-shaft assembly off of the other Outback I had, which had a 5-speed, and the center differential is in there. I did not see a center differential in the tail-shaft housing of the automatic. The rear differential is at the rear of the vehicle on wagons with standard and automatic, just like a rear-wheel drive car.

Anyway, being that the front differential is divorced from the transaxle, it may be easier to service. I'll have to wait until I get one of my other cars on the road in case this repair takes a while. I remember when a wheel bearing went on my other Outback, it whined like all heck, so that could be the case here. We shall see. Thanks for the insight.

On another note, my air flow meter (or MAF sensor, not sure which this car has) began humming a few days ago. What would cause that?

Thanks,

James

 

[1 Lucky Texan]

hmmmm....on some Subarus that first got ABS brakes, I THINK I recall an issue with the pump humming - but not sure how a MAF could hum. maybe a relay in the area is buzzing?

check the air box 'tabs' ,on some soobs, they are easy to miss inserting the upper box - or they are cracked apart. Might make a noise but usually reported as a 'whoosh'.

you seem to know what you're doing so, dunno if I can help really. Most folks wouldn't mess with taking the front diff off to rebuild. It's been done of course but from reading, setting the preload for the output bearings (w'ever they're called) is tricky. Most people just get a whole trans to swap in.

Subaru wheel bearings are notoriously tricky to diagnose. Best way is probably to get a mechanic's stethoscope if the bearing doesn't 'rock' up-down.

 

[0341_Jarhead]

You know what? That pump (or at least a manifold) is in the same area. That might be the source of the hum. I'll check the other stuff, though, as well.

Setting bearing preload is not for novices, but it's honestly not that difficult. It's a matter of measuring and shimming (I work as a mechanical engineer, so I deal with that kind of thing almost daily), but the real bear is getting everything apart. E.g. changing the head gaskets - especially the timing belt - was a huge pain on this car.

When I got the steering knuckle removed from the car with the noisy wheel bearing, I spun it and heard the same "buzzzzzzz" sound I heard while driving. The real pain in the butt is getting the hub separated from the inner race of the bearing and the bearing from the knuckle. Everything is press fit, which is a horrendously bad idea since everything then rusts together. I can tell you the yield under bending force of the grey-iron steering knuckle is about 12T. When I was trying to press the bearing and hub from the knuckle, it broke at about twelve tons of force. I had to rob a knuckle off the Outback I'm driving now. I replaced both wheel bearings, ball joints, CV axles, etc. Then, a tractor trailer rear ended me and totaled the car.

Again, thanks for the help. Have a good weekend!

 

[1 Lucky Texan]

you guys that deal with rust all the time - it seems really horrible.

newe cars have HBAs but, those can also be difficult to get axles out of - or get them out of the knuckle....


worked with some MEs in my previous career on electromechanical stuff (downhole 'wireline' equipment) - so much creativity and knowledge but open to suggestions from anyone, not snooty like some other disciplines.

 

[0341_Jarhead]

Yeah, rust is part of life here. At least it's not so bad here as it is on the coast. I was stationed along the coast in NC years ago, and I quickly noticed that they battle airborne sea salt 365 days a year. Cars would typically begin to rust at the center of the roof and the patch would grow from there. That was usually accompanied by several growing holes along the sides of the body.

I discovered why I didn't see the center differential when I changed the "C" solenoid: they only come in the standard transmissions.

I need to find a service manual so I can see how to go about servicing the front differential. It looks like everything can be done with the transaxle in the vehicle.