posted in the 1st gen forum but maybe that was wrong since I got zero feedback, so here goes nothing:

2008 Honda Fit Sport, 5MT, 150K miles. daily driver in rush hour downtown metropolis traffic

3 things here

- Getting harder and harder to shift and usually cannot shift into 1st gear or Reverse, have to shut car off, shift into them, then turn back on.. Trusted mechanic without tearing anything apart says it needs new clutch..

- Getting code PO420 on/off, but now is staying on longer and longer,for weeks at a time, then randomly goes off for a few days. New cat or??

- Engine seems to violently shake or at least shudder, usually only coming into and then out of 1st gear.. motor mounts or?


My questions are a follows:

1. Is there a quick overview or guide on clutch replacement? 3 Places quoted me $1900 for the job but I bought the Fit for $2500 so thats a bit rough.. Friend of a friend will do it for $800 if I buy all the parts. Research says this is what i need:
   
   Clutch Kit + Flywheel
   Clutch Kit + Flywheel
   Clutch Kit + Flywheel
   Clutch Kit + Flywheel
   , but is there anything else I should buy? $800 seem fair?
2. From what I read, clutch replacement is involved process on the 08 Fit since you need to pull the transmission, so anything else I should have address at that time?
3. If I do need a new cat, where to buy from and whats the quick overview replacement process like?
4. No idea on motor mounts or that shakin..
   
   anything else I'm missing or should be aware of?

much appreciated!!

 

Going to ramble--post too long.

Shaking? How's the clutch pedal free play and fluid level, assuming it wasn't topped off (not good)?
Maybe the clutch isn't being disengaged fully when you press the pedal all the way down due to some clutch wear, and lack of pedal adjustments. Which would mean clutch is still ok, but then again 150K in city traffic on a stock clutch sounds high. My original brake pads should last 125k on one of my cars, so 150K clutch could be an outlier too.

If there is a nut in the pedal assembly, then there's probably an adjustment.
Pedal - 2008 Honda Fit 5 Door SPORT KA 5MT (hondapartsnow.com)

Can't tell what model clutch kit from the amazon link, but I'd use Exedy too / only on a Honda daily driver.
https://www.exedyusa.com/browse?sear...%20fit%20sport

If you know how much seal materials been used up by eyeballing the amount of black during clutch fluid changes, or inspected the fluid system for weeping, then your should be able to guess at whether CMC and CSC also need replacing. Fluid levels should not have been topped to have an extra check on clutch wear level, just like don't top off brake fluid.
CMC should have already been fixed (delay valve removed) for more deterministic operation. Maybe good time to do so now if changing the clutch.
12 oz brake fluid if replacing CMC and CSC.

Have some anti seize or high temp grease for the CSC ball during transmission re-assembly. Likewise input shaft.
2? qt Honda MTF4 unless you're trying some higher viscosity stuff. Save and reuse if fresh. Drain crush washer is the same 14mm (94109-14000) as the oil pan because Honda. 20mm (94109-20000) fill washer--you could replace that too, but whatever. Have fill-from-top "tool"--a pain to pump from bottom, and MTF stinks.
Dielectric grease for battery terminal after you put it back in. Airbox comes out too to get to fasteners and sensors on top of the transmission.
Hood up, check the 3? eng & trans mounts. Not sure on 08 Fit GD. Should be 1? more on the bottom.
On jack, etc, check sway bar links, and other suspension rubber parts in advance so you have new one while the wheels and axles are off. TRW, not MOOG.
Have NGK O2S ready if that really if a problem--flare or correct tool to remove.
Trim remover & replacement fasteners for the engine splash shield.
Penetrating fluid--axle nuts. Cap off trans where drive shafts came out if they'll be out a while.
Replacement cotter pins as needed for wheels or clutch hydraulics.
Lots of brake clean--and don't breathe in the clutch dust. Mask, lots of gloves, safety glasses, work light, bungee cords or maybe zip ties, extra stands and jacks for the car/engine/safety.
Don't lose the alignment dowels.
Check bearings, etc when gearbox is out. Check the new parts' bearing before getting in the car. Maybe replace flywheel pilot bearing with Exedy clutch kit bearing if new flywheel's feels wrong. Likewise check new pressure plate's fingers.
Maybe blue loctite on flywheel fasteners. Wiggle input shaft (with clutch alignment tool) when torquing fastening flywheel krispy kreme cross.
Clean input shaft. Lightly moly grease input shaft splines and shaft body? and blob clutch release fork metal-metal like throwout bearing, light moly throwout bearing on pressure plate finger side; grease may come with clutch kit.

P0420 root causes are many, and should not be left alone. Cats are not cheap, can still be long leadtime, and you don't want the replacement to be killed by unfixed problems. Some places to check:
https://mechanicbase.com/trouble-code/p0420/

OE Cat should be more efficient for long term operation, but you'll cry.
18160-RME-A00 - Honda Parts Now
https://www.rockauto.com/en/catalog/...converter,5808

Clutches are typically 4~10hrs labor * 138.12$/hr@WI
https://www.vehicleservicepros.com/s...-by-state-2021
Probably don't need to remove subframe, but likely will need to shift stuff out of the way or the transmission out without hitting stuff.

Also, prepare swearjar.