hi guys im finally getting close to putting my gsl se under carriage into my GS and im wondering if the flywheel on the 12a and starter are just plug and play on the gsl se tranny, i know they are different sized flywheels so im wondering if the teeth will catch on the start in the new tranny and if it will all just bolt up

 

Yes

 

But if you had an auto tranny or lightweight flywheel, you would need the Mazda counterweight. The Mazda counterweights are different part #'s between 12A and GSL-SE 13B. What is the difference? I assumed it was weight.

NEVER MIND just reread OP's question. I thought he wanted to mix-andmix-and-match13B flywheels.
It's been a long week.

 

It's an exact bellhousing match to the 12A trans. You do get a taller 5th gear and a vented bellhousing with the SE trans.

 

What's the benefit of the vented bell-housing? I've noticed the zinc plated diverter on the driver side of the trans bell housing and the hole under it that seems to allow the clutch dust to flow out that hole, but was always curious why Mazda bothered to add this part. I've never had a problem with clutch dust causing problems. Anyone?

 

always thought the same .... never liked that 5 gear

 

???

 

Just that,to vent the bellhousing and keep the clutch cooler. Engine makes more hp/tq than 12A. Think of it as flow thru ventilation,air pulled thru rear facing vent on case by spinning flywheel/clutch assembly and driving down the road that air is exhausted out of the lower hole. Not about clutch dust. Look at the vane on front of driveshaft where it goes into tailshaft of trans purpose is to keep it and bushing in tailshaft temps down.

 

Ah, keeping the clutch cooler sounds logical on Mazda's part. I'm sure they had the same setup for the 12AT starting in 83. Anyone know?

 

wrong quote

 

they did, same part numbers, M511-17-100A up to November 1984, and then M511-17-100B after that, the 12A/ JDM 6 port 12A got M503...