5MT clattering and whine

[Setnev]

I picked up an 02 Forester yesterday for $800 that the PO said has transmission issues but he said it drives and shifts fine. I took it out for a drive and put a little over 100 miles on it. It's got 204,450 miles on it.

 

The best way to describe the sound is it sounds like valvetrain chatter when you have a sticking lifter, only it sounds like every lifter is chattering and you can feel the sound in the shifter too. It only happens when you take away load. As soon as you accelerate, the noise is negligible. There is also a very noticeable whine to it on deceleration along with the clattering. I asked a buddy of mine about it and he said its the bearing in the tail shaft of the transmission, but I'm not so sure it's that. It sounds like a gearbox that that has run dry of fluid and the gears are being noisy as a result. I checked the fluid and it looks new, clear, and at the full mark. The previous owner said he recently replaced it with Valvoline SynPower Synthetic 75W90 GL-5 (left an extra bottle of it in the car) and said the old fluid looked good with no metal in it, but I've been reading that the 5MT doesn't take kindly to synthetic gear oil due to it being "too slippery". The transmission indeed shifts very smoothly (like new car smooth) and has no vibrations, even at 75 MPH.

 

I have a couple of options at my disposal if this transmission is junk:

- I have a known good 5MT 3.90 transmission that came out of my old 99 Legacy 2.2 that I can swap the tail shaft gears into, but that tranny has over 230k miles on it.

- I was at the junkyard today and found a 5MT 4.11 transmission that has 134k miles on it (according to the odometer) from a 98 Legacy GT 2.5, but I'm concerned about compatibility with the 02, considering the 02 is a Phase 2 transmission and the 98 is a Phase 1 transmission. Both my 02 and the 98 have push type clutches with the slave cylinder on the front of the bell housing.

 

Questions:

1.) What is the noise I am hearing?

2.) Could the clatter and simultaneous whine be a result of the synthetic gear oil being used?

3.) If I use the 5MT from the 98, what needs to be changed over to make it work in my Fozzy?

5.) Any other options you would suggest?

[RustyRuu]

I came across a similar problem when working on my old 96 before parting it out, considered doing a hydraulic clutch conversion since it was cable but parted it out instead.

 

you may just need the clutch fork and slave from the foz and move the position of the pivot ball bolt thing. Apparently there are already holes tapped in the transmission case to do so.

 

it doesn't seem too hard since you can see all the old hardware from the foz as you take it out, just pay close attention to where the pivot bolt is for the clutch fork and change it over accordingly.

 

now i'm second guessing myself and wondering if you can just use the legacy bits and convert it to the push style instead. I maintain an 09 forester that will need a clutch very soon they have the push style clutch slave.

 

maybe other small things need to be swapped to if the hydraulic lines are different lengths, and other things i just cant think of at this time.

 

I hope this helps, or at least you learned something new to research

[Setnev]

Clutch, TO bearing, fork, and pivot ball, master and slave cylinder are brand new. Guy gave us receipts that he had it done by Subaru because he was a OTR truck driver and didn't like how sloppy his clutch felt in comparison to his truck. It's got the updated components. This guy didn't spare any expense owning this car, which is why I bought it and didn't fight him on price.

 

He just got sketched out when the dealer told him it'll be $1,600 to remove the transmission, disassemble and diagnose the issue, but the tech told him it wasn't a clutch noise.

 

He took it to a local shop down the road (who knows nothing about Subarus) that said the noise sounded like it was coming from the back of the transmission and told him it'll be $800 to remove and diagnose the transmission and that he thought there was noise coming from the rear diff, so recommended replacing that as well.

 

In my testing, there was no noise coming from the rear differential. When the vehicle is rolling you can hear a hum and a clatter, but only the hum is prevalent when the transmission is under load, the clatter is silent and can be felt in the shifter. Again getting me thinking it is the bearings in the tail shaft, which I recently found out is a very common issue in 5MT's and costs $140 to replace all four bearings and about 3 hours of time.

 

I think I'm going to remove the tail shaft and check the condition of the bearings. At least I can work my way forward from there.