While installing an M-Factory LSD into my B18B1 (LS) transmission I made the dreaded mistake of damaging several teeth on the speedometer gear ring that sits on the differential.

You might be thinking so what? It’s just a gear so it’s probably cheap.

It’s just a gear, but finding one is next to impossible though because it was never sold by Honda under any known part numbers so finding a new one is a pain.

If your lucky you can find an Integra to pull the differential from at a local junkyard but given how old these golden era Honda’s are now there’s not many left in the junkyards.

K Series to the Rescue

The situation isn’t as bad as it sounds though because a K series speedometer gear will fit!

I came up with the idea of trying a K series gear after I spent several hours looking at other Honda transmissions to see if any parts might be swappable into my transmission.

I never found anyone that could confirm fitment, but I did find wild stories such as B series differentials working in K series transmissions and also noticed they shared some parts such as the differential bearings.

Willing to take a gamble I decided to order a new VSS gear ring for an EP3 Type R: 41312-PE6-310

And as it would turn out, it’s a perfect match for the B series differential speedometer gear. It even has the exact same number of teeth (23) and the same dimensions!

K-series ring on left, damaged B-series ring on right.

Best of all Honda still sells them for roughly $70 bucks each. https://www.hondapartsnow.com/genuine/honda~gear~speedometer~drive~41312-pe6-310.html

Note: Different K series speedo gears have different teeth counts. If your not trying to adjust your speedometer ratio you’ll want to stick with only the EP3R ring.

Install Pictures

The new EP3 ring pressed on nicely to the M-Factory LSD.

All buttoned up.

TLDR

Order a EP3 Type R Speedometer gear ring (part number: 41312-PE6-310). It’s a perfect fit with the same number of teeth** as the LS speedometer ring gear.

** I don’t know how many teeth the GSR or B16 transmission have so this may not work for them.