double syncro on 2nd gear?

[dylan0451]

SoloMiata said:

Mazda has two 5 speed transmissions. One is used in NA applications (AKA 'type 2' or Model M) and came on such cars as the RWD 626, 79-85 RX-7, 86-91 NA RX-7, B2000/2200 truck, and Miata. The other is a stronger unit that came on all turbo RX-7's, 929, B2600, and MPV.

Within the type2 versions only the bellhousing & tailshaft cases and gear ratio's are really different between models. All the guts of the Type 2's are nearly the same and mostly interchangeable. The major differences came in '81 when the shifter was made remote, in '83 where some bearings and shafts were made larger and in '94 with improved seals and a double cone 2nd gear synchro. Between models the input/output shaft lengths may differ slightly (~ 1/2") so always measure. The 79 through mid-83 tranny guts should be avoided if reliability and torque rating is important.

it doesn't state whether that meant that all 1800 mx5's have the uprated syncro box, but i assume so. can anyone concur?

[OnlyMX5ives]

Never heard that and I've just swapped my 1.8 94 box for a Mk2 version as 2nd gear syncro was crunchy (third wasn't much better).

Mk2's have certainly got a revised box and don't tend to have the syncro problem.

[dylan0451]

hmmm, are the mk2 boxes a straight swap? or i should add, are they a straight swap for 1600's ?!

[OnlyMX5ives]

dylan0451 said:

hmmm, are the mk2 boxes a straight swap? or i should add, are they a straight swap for 1600's ?!

Yep but you need the gear lever too.

[dylan0451]

ok... i wouldn't be particularly impressed if i didn't grab it with the box but thanks for the heads up!

all mk2 boxes 6 speed or was that just the 'more sporty ones?

[OnlyMX5ives]

No 90% + aren't.

Personally I'm not a 6 speed fan, the ratios are too close and really you need the higher ratio diff too.

For the 6 speed you really need the starter and plate too.

[MX-5 Lazza]

I have a 6-speed but prefer the 5-speed. It's has more accurate gear changes. It's too easy to get "lost" with the 6-speed especially when racing through the gears.

[dylan0451]

i see, that makes sense... wasn't dead set for a 6 speed box by any means just wanted to make sure it would still fit if thats all i could find!

do the mk2 boxes retain the same ratios as the mk1's? i assume as mentioned that just the final drive changes?

i was thinking about a recon'd box, but if there is a stronger one with better syncros like the mk2 i may as well just grab as lower mileage one as i can find

[OnlyMX5ives]

As a guide price I supply used Mk2 5 speed boxes for £95.

As you are in Essex no doubt there is someone breaking one close to you, to avoid postage charges.