Got the P1443 code taken care of last week just in time for a whole new issue this week. 03 WRX 4eat (135k) is making a gear whining noise when the throttle is applied. Ceases when off throttle. Coming from the front. All wheel bearings are solid with a new one (right front) installed several months ago without issue. Front diff? How to troubleshoot? Safe to drive? As always, thank you. -Rick
I haven't delved much into that stuff, but it does sound like front diff. I'd be shaking the axles around looking for play in the diff bearings, and I'd drain the front diff gear oil through a coffee filter. Some shavings are normal, that's why they come with a magnetic plug, but if there's a lot, or they're large, that's probably the problem.
I agree, most likely it's coming from one of the differentials if it's only under load. If the internal bearings get worn the gears can shift a little, just enough that they won't mesh up properly. That would cause both whining noises and after a short while some noticeable metal shavings in the fluid. If the fluid gets old or contaminated, changes viscosity, and is no longer providing the necessary lubrication it could possibly cause some gear noise as well. Might be worth flushing and refilling the trans/diff fluids to see if that helps before rebuilding or replacing.
The diff fluid was changed less than 1K miles ago. Same with the trans. Everything has been fine until recently. I will give them another dump and see what happens.
It turns out to be the front dif. How to proceed...replace tranny/diff or repair the existing one? I would have to take this in to have it done.
Depending on the trans you have (or want to upgrade to) if you can find a known good one it might be a little cheaper than a rebuild but not by much. I'd expect you'll need the diff gears and bearings replaced so not something most people would do themselves. Center and rear diff are pretty easy but if I'm not mistaken you would need to disassemble the trans to get to the front. Sounds like you have a little research to do, maybe calling a few shops for rough estimates on a rebuild or replacement and checking around to see what you can find for used or rebuilt transmissions. If you haven't checked already the transmission code should be on a label stuck on the bellhousing.
Rebuilding a manual transmission is sorta fun IMO. It is WAY easier than building an engine. I'm not familiar with our transmissions though with the diff built in. If it's like setting up a GM diff with all shims and stuff, that's a total pain. If you're considering rebuilding it, maybe start with researching the diff setup part of it. I'm guessing they've got a better solution than the GM put-it-all-together-check-it-it's-wrong-take-it-all-apart-put-a-shim-in-it-put-it-all-back-together-check-it-it's-wrong-take-it-all-apart-put-a-shim-in-put-it-back-together... you get the idea. How much are used 6-speeds? I'm guessing that's what everybody wants... I'll admit that I did indulge in researching the various dog-ring gearsets from UK. SO expensive but I bet they are AWESOME. I built a dog-ring straight-cut gear setup for the T-5 in my perpetually unfinished '73 Vega GT track car. That was really fun.