Strongest 4g63 compatible FWD box?

[mitsuturbo]

So, i take it "the F5m31 is to the F5m33 as the W5m31 is to the W5m33" would not be a true statement, based on what has been said here. Correct?

The w5m31 is a WEAK transmission. I know the f5m33 seems pretty strong, but i've known a few people that went with a built w5m33 in their FWD cars; I was told this was for added strength. /ubbthreads/images/graemlins/dunno.gif

 

[Wizardawd]

The last 2 numerals is the torque rating, higher number equals higher strength. The 1.8l dsm 5-spd had F5M21 as a code.

 

[fuel]

I had an F5M31 in my 7G Galant VX-R which had a 200hp MIVEC V6 engine and it gave no troubles whatsoever. I don't think an F5M33 exists?

 

[Galantvr41062]

Buy a shep stage 4 with a welded center diff or similar, but do not bolt a tcase on.

~John

 

[Wizardawd]

F5M33 is the 89-99 Turbo FWD T/E/L trannies.

Here's a couple links to show different AWD trannies and their codes:

click

And here's a breakdown of gear ratios per gear per transmission:

click

Might help.

Wiz

 

[bazeng]

Hi All,

I'm looking to go back to a FWD gearbox.
Seems wasteful to run an AWD VR4 RS box in a FWD daily.

So back to research.

The original AMG box was an F5M31-2-ZQZK.
Open front diff.

Photos below:

 

[mitsuturbo]

F5M33 is probably the way to go if you're looking for a FWD M/T. This would be from the 89-94 DSM. I'm not sure if there was anything equivalent offered in any sort of tangible numbers outside north america. Since your engine mounts are on the block, being a galant.. i believe you could actually run the 2nd gen DSM fwd 5 speed as well. Essentially any F5M33 would bolt up. Unless i'm forgetting something about the 2g GS-T trans vs the 1g.

 

[FlyingEagle]

You would need the matching spline count differential in those transmission if I don't have my DSM FWD transmission mixed up.

< 92.5 below used the smaller 25 spline count axles.
> 92.5 on-wards used the larger 27 spline count axles.

You can install FWD or AWD diffs in both transaxle cases from this generation.

I installed the AWD 25 spline Quaife LSD (any AWD diff from this era will fit with mods) into the FWD F5M33 91-92.5 for the USDM. You require ball and cage bearings x2, lots of shim kits from Mitsu, and a competent transmission builder to measure out the total space and preload/free play to make this work. I got ahead of myself and installed the first bearing that sits on the bottom of the diff (with the case separated and looking for the ring/crown gears to line up flush) and it was aligned WAY too far down. If I had measured it all out including the component depths I would not have had this issue and smoked 1 bearing to remove it again. There needs to be shims between this bottom bearing and the diff housing mating surface! Very important! Then the whole trans needs re shimming on the individual gear shafts/bearing races to the case once torqued down. I was too stressed over that and got an experienced trans builder to do it. Left it with him for a few weeks and paid cash.

Your market I assume, means you want to stay away from our "1990" early single year oddball DSM transmissions, and use the 2.5 year run, pre 27 spline units. Make sense?

All of this assumes that all AWD cars were 25 spline count for the axles versus transfer case ... that is another spline count issue too?