Drivetrain clunking 1st gear
 

So I was driving around this morning and while in stop in go, just coasting in first I heard a clunk and I thought I ran over something metal? Looked back and didn't see anything so continued driving. I noticed now when in just driving in first gear I hear a clunk, clunk,clunk, clunk, clunk, clunk, u get the point. When I push the clutch in, the sound goes away and it doesn't happen in any other gear, just first when driving.

If it walks like a duck, talks like a duck, then does that mean my transmission needs a rebuild?

I'm at work now but I plan to have the car towed home and then start from there. If I see nothing wrong visually, should I just start with draining the oil? Also what other things should I try before I have to start digging into it. Never done the clutch/pulled transmission from this vehicle so if it comes to that, I'm sure that'll be fun...

When was the last clutch installed? It may be something relating to the clutch assy & not w/the transmission gears / synchros.

I would start w/putting the EvO on the lift (or jack stands)& getting underneath to do a visual first (take extra precautions to ensure the EvO will not tip off the stands).

With the trans in neutral, rotate the left / right front wheels & listen for any unusual noise. If you detect issues w/the wheel rotation the next step may be to separate the trans from the engine (that process may expose the issue w/the clutch (hopefully thats all it is)

Just my ideas! Keep us posted

Clutch was replaced like 30k miles ago with oem throw out bearing. It has a good 30-40 autocross events under it. I'll try to see if any other scenarios like you mentioned for noise.

Is it happening only in first gear?

Yes. Had someone stand out and listen as I drove by in 2nd, and reverse, no noise. Other gears when driving to work when issues started no noise in any gear except first.

Actually happens in all gears. It's just a lot more noticeable in first gear. Was easier to tell with car up in the air.

Is clunking in the back? Does it sound like it's coming from trunk? And it only happens when you step on or let off gas pedal?
https://cimg9.ibsrv.net/gimg/www.evo...6e97d3fac6.png

I went under car with it in gear going and it came from inside the transmission house or very near the clutch.

Oh. Look inside through peep hole to see if anything looks broken.
https://cimg8.ibsrv.net/gimg/www.evo...8edc07da02.jpg

so I drained the oil. Something busted for sure.
https://cimg2.ibsrv.net/gimg/www.evo...0bea2b495f.jpg
https://cimg7.ibsrv.net/gimg/www.evo...b617330a9c.jpg

Are you pulling your tranny out and sending to a rebuild shop?

Seems like the plan. Never done it before so this will be interesting and im sure painful learning experience. At this point I wonder if sending in anything else with it is necessary. Car has 118k on it and its autocrossed a lot on. Wonder if rear diff or anything needs a refresh or some sort of new diff rebuild layout.

If the car is going to be down, get the rear diff gone through and a 12 plate upgrade done, billet side cover, etc, won't hurt if you have the money. Same with getting the tcase gone through and doing the 10mm bolt upgrade, etc..

Other than swapping all fluids, if needed, just re-stacking the rear diff plates, if you haven't already. If you want something more aggressive or notice the rear end not biting like it used to, an upgrade, like letsgetthisdone mentioned or at least a Weir 12-plate, to hold you over, is a good idea, depending on time and budget. Hard to say, as we don't know how hard those 118k miles were.

So is it possible for metals to go into the transfercase/front diff? I thought I read somewhere the front diff and transmission share the same fluids and if that's the case I would be worried about the front diff having some metal left in it.