M2B4 5th gear

LIE · Post by **LIE** » Wed Mar 20, 2024 8:03 am

Hi, anyone is parting out M2B4 gearbox?

I'm looking for the 5th gear.

The code should be 23581PX5J41, ratio 787.

LIE · Post by **LIE** » Wed Mar 20, 2024 9:48 am

Actually, loks like It firts from more than M2B4:
https://honda-tech.com/forums/honda-pre ... t-2548441/

Accord U2L4, U2J4, H2S8
Prelude M2J4, M2A4, M2B4, M2J5

Post by **Merlin** » Mon Mar 25, 2024 9:59 am

Out of interest, what are you up to? Are you looking for that exact ratio to put into a different box? Or is it a replacement for a broken gear in your M2B4?

LIE · Post by **LIE** » Mon Mar 25, 2024 12:52 pm

I had an issue, switching to the 5th gear(grinding in high speed, without aligning idle rpms) now when the engine is out, I opened the gearbox and noted, that the teeth on the outer ring(8th part) and the teeth ends on the 5th gear(5th part) are not sharp, they're round and seems worn.
I just wanted to replace the gear and leave the internals as is, not changing anything yet.

Good for me, that the old engine in my prelude was f20a4 and those came with U2J4 gearbox, which I still have. Opened it up and there's decent gears with minimal wear.

The fifth gear for all mentioned gearboxes is the same ratio.

Post by **Merlin** » Mon Mar 25, 2024 1:50 pm

I had 5th gear grind in my 4th gen at high rpm but it was a synchro issue. I got the synchros changed it was sweet after that.

LIE · Post by **LIE** » Mon Mar 25, 2024 2:47 pm

Yes, The synchro will be replaced as well.