89 Manual Transmission Questions

[AaronB31]

I've got an 89 MM with the 2.0 G63B carbureted engine and a 5-speed transmission.

I'm in the planning phase of doing a 4g63t swap. Most of what I'm finding on the internet tells me that the 5-speed will bolt up to that 4g63t (I understand I'll need to move the motor mounts around for the new engine).

I want to be sure I know what I'm doing before I start sourcing an engine, so I did a little more research into exactly what transmission came in this truck. It appears that it should be the "narrow-block" KM-132.

1. I just want to be sure that is the transmission I have. Is there any other 5-speed that could have come in the 89 2.0L? Im reading that some mitsubishis came with a "KM-132-N" and that's different somehow. Is there a way I can look at it from underneath the truck to confirm? I'm aware you can measure the distance between bellhousing studs to do this, but I don't want to take the transmission off as I'm still dailying the truck.

2. Will ANY 4g63t will bolt up to this narrow-block KM-132? Im reading a lot about the difference between 6-bolt and 7-bolt engines. From what I understand, you need the flywheel (either 6 or 7 bolt) that matches the engine. Can either a 6-bolt or 7-bolt engine and flywheel be used with my KM-132?

3. Does anyone know how much power these little KM-132 transmissions can hold up to? Just need to know what to limit my engine build at.

I honestly tried my best to dig up these answers before asking. I appreciate any insight you guys may have to offer.

[4doorciv]

My transmission still holding up. Km132 out of your 89 should bolt up as mine did.

[pennyman1]

Buy a tuff pan for the tranny and the tranny will take almost any amount of power you can throw at it - LSR Mike ran his with one and 450+ HP with no issues.

[DroppedMitsu]

Only one type of KM132 truck transmission that I am aware of, never heard about the "-N" version. All 5-speeds that came behind a 86-89 g63b 2.0l will be a KM132. Basically if its a truck KM132 its a KM132 that you want/will work. They will bolt up to any 6 or 7 bolt narrow block 4g63t(90-99). Later 7 bolt 4g63ts that came in the Evo's use a slightly different block that is missing a (truck)motor mount provision so to use it you would have to engineer a way to mount a motor mount on one side of the block.

The consensus is that these transmissions can handle up to about 275-300HP before they grenade. The main killer of them is the tranny spreading apart from the torque/power which wears/takes things out inside. A thick oil pan(TuffPans.com) will help combat the issue as the stock stamped sheet metal oil pan lets the transmission flex too much.

[4doorciv]

Lol. I'm on the oem oil pan still so it can hold power in its stock form. My third year syncro is going out and first gear pops out intermittently. It's due for a rebuild with new syncros but I'm going to swap it out for something better instead. In the saving money stage. Lol. How much horsepower are you looking for?

[AaronB31]

Thanks for all the feedback! I wanted to know what the tranny could take before I set HP goals. I was thinking of doing a setup like what you describe in your signature, 4doorciv. I probably will spend the extra buck and get the tuffplate. How much did you end up investing in that setup, if you don't mind me asking? And do you have a build thread? Im hoping to manage to pull a 4g63t from a wrecked DSM or something, but I know the internals and supporting mods will add up pretty quick. Just looking to get an idea how much to save up.

[4doorciv]

2 engine failures, on my 3rd turbo engine. From the donor car I went from a 14b, small 16g, to a evo3 16g. Stock cast manifold to a pace setter tubular manifold but I satisfied with it. 2 exhaust setups, different engine harness, ecm link, etc etc. I did my first turbo setup less then 2k to get together with a donor car. Bought stuff to make it work only to upgrade it later. Spent more then your willing I'm afraid. Mostly due to trial and error and the engine failures took raging fists to my wallet. Lol.

[4doorciv]

I'm saving up for a t56 swap in the truck. Then to a bigger turbo. Looking to keep the open diff rear end only cause of the amount of rain the truck will see.

[dash]

several 4g63 turbo tucks gone 12s on stock 5 speed. Several starions gone low 11s on stock gearbox
If making enough torque to warrant a T56, I'd think an open diff would be a waste of time
some full street starions seen 4-500 ft-lbs tq to the tires

[4doorciv]

I would agree with you if I didn't want more rwhp. I see the trans as my weakest link, and it's what I feel is holding me back from more mods. If they want to go that fast on the stock trans it's on them. Ive been wanting a 6 speed car, and a bigger turbo for the truck for a long time. If I put a fp red at 23 psi I'm almost positive I'd shred a gear or 2. Not wanting an LSD trans is only because I'm going to see freeway speeds in the rain. Spooky when you start to hydroplane and the rear end wants you to do a few donuts. Lol.

[dash]

One wheel spinning should reduce the stress on the gearbox drastically
10sec 4 cylinders trap in 3rd gear, mph in the 120s. Why 3 more gears ?
FP red @23psi... on the freeway in the wet ? ...sounds like a recipee for a disaster
Lotsa powerful rwd trucks about that r not flying off wet roads. Vast majority r LSD
.... or is that some trait of these minis when u power em up ?
That right foot may be more harmful than an LSD - lol
Just curious about the goal of the build. Sounds tuff

[geezer101]

These trucks are skateboard light in the rear end - add boost, an LSD + wet road = RIP. It isn't hard to get them sideways in stock form or light up a tire from a standing start (PO barrel rolled his truck twice, lucky me gets a donor truck out of it...) I'm considering using semi softs on the 15" steelies my donor truck came with. I can get them relatively cheaply and will offer some decent grip over the Yokohama Delivery Star tires that are on them now. I think improved tire grip VS LSD is an acceptable trade off.