6 speed in a 1992 VR4`

Yes, all of our transmission services require a core unless you purchase one from us.

Both transmissions have their pros and cons. Neither is harder for us to get parts for, we are manufacturing gears, output shafts, bellhousing braces, bushings, custom seals, and hubs and sliders, and we worked to get the carbon synchros made.

A ton of parts have been discontinued by Mitsubishi, but we are committed to keeping these things running and in race shape.

The 1/2 synchros are exactly the same between the 5 and 6 speed. The 3/4 synchros in the 5 speed are smaller and were original made of material that was prone to be very picky about fluids, but later OEM replacements and the carbon synchros we offer correct that issue. The 5th gear syncho on the 5 speed is tiny.

So, in perfect condition the 5 speed will make the 1-2 shift better than the 6 because the 6 speed input shaft has more mass to accelerate and decelerate. The 6 speed 3/4 typical shift better than the 5 and there is almost never an issue with 5 and 6 on the six speed, but sometimes the 5 speed will wear out the 5th synchro and start to grind because it is undersized.

Reverse is torn up bad on the 6 speed cars about 60% of the time and the parts are $1500, so that is a bummer. We just installed the last new reverse hub and slider yesterday, so its even worse, but we had made new gears.

In perfect condition both transmissions can be made to shift extremely well and we build all our units to that standard. We race and test the parts personally and care about these cars.

Don't launch a 6 speed car hard without having an internal bellhousing brace as its very weak and leads to catastrophe when it breaks.

This is what I am talking about here:

Bellhousing Brace Installation – R'venge Performance (rvengeperformance.com)

I could go on for some time, but let me know if you have any questions or need help.

I won't even attempt to pretend to be half the expert Chris is. All of the advice he gave you is spot on and he's a proven guru! But here's my "experienced layman's perspective" on your post / problem. I've owned many 5-speed TTs and several 6-speeds. The 2nd and/or 3rd synchro problem is equal in both. The primary underlying cause for this, in my experience, is a clutch that doesn't release all the way. This can happen with the OE clutch at less than 40k miles sometimes - especially if it's primarily city-driven. The fingers on the OE pressure plate aren't strong enough. They get bent slightly, over time. When that happens, the geometry is wrong. You won't realize it, but the clutch doesn't release completely. This puts a lot of stress on synchros when you shift. Why does 2 & 3 go first? Because you shift to those gears way more often than 4/5/6. When the PP fails, it will also make the clutch pedal heavy. It happens over time, so a lot of long-time owners don't notice it. But I can tell a good pressure plate in one of these cars from a bad one in about 15 seconds of driving. Probably 50% difference in pedal weight. You mentioned that your clutch engages just a tiny bit off of the floor. This further reinforces my believe that you pressure plate is the issue. Yes, there's some pedal adjustment. But you really should never have to adjust it unless you're compensating for a worn clutch assembly. Even then, it's only a small amount of adjustment available.

My advice... First of all, flywheel shimming is not a thing... at least not one you should be doing. If your transmission is shifting smoothly, with no grinding (I was a little unclear on that, from the OP), check your vac assist to make sure it's working (they usually are, unless someone screwed around with it). If that's good, then replace clutch kit and change fluid with Synchromesh. ONLY with Synchromesh (Pennzoil or GM... it's all the same). The factory-spec gear oil is WAY too heavy. I realize I'm opening myself up to controversy here and everyone always has their own opinion on fluid (even Chris might tell me I'm wrong). But I've done this enough and seen good results enough to consider it "tried and true". If there's no grinding, your 6th gear and 1st gear shift problem might be L/R shifter adjustment. I've experienced similar before, in a 6-speed. Again, slightly unclear on your exact symptoms. Oh, one more very important thing to check... Is there an aftermarket BOV? Make sure the shift lever on the trans isn't hitting it! Very close quarters down there. I bought a Stealth last fall that required excessive effort to get it into 5th and 6th. Turns out it was hitting the big chrome BOV. Reworked that a little and it shifts easy as pie now!

Best of luck to you, getting it fixed up. Nice to see new enthusiasts around here!

OK, I found out the vacuum assist for whatever reason was blocked off. Hooked it back up and the clutch feel is really nice now. I now have about 1/2 inch of free play at the top of the pedal. So the 2 problems I have left are........ the gearbox is rough. Standing still you can feel the car try to move putting it in reverse or first. You would have to slam it in gear if you do not go from 6th back to first. The car was rolling barely forward at one time I was testing and it was still having to be forced into gear. 6th then into 1st it is pretty good. Reverse grinds 3 out of ten times going into gear. After you get moving it is livable. The last drivable thing is the throttle is really heavy or stiff. If i pull on the cable behind the plenum it is easy. If i pull on it at the cruise control box it is easy. I used BG NForce on the cruise mechanism and into the cables and on the external part of the butterfly and no change. Between the throttle body and cruise is not the issue. I have not had any luck finding new cables. Any help as always is greatly appreciated.

Sounds like you still have a clutch release problem. If you feel the car trying to move with the clutch depressed fully, it's not disengaging all the way. Could be air in the line. But more likely, it's a worn/damaged pressure plate like I described before. Or possibly a failed throwout bearing. And if it's that bad that you can actually feel it trying to pull, it has likely wiped out some synchros. As for the stiff throttle, sounds like it's either A) the pivot point on the pedal binding up, B) something up in the dash interfering with the movement of the pedal linkage, or C) the cable from the pedal to the TB is binding up... possibly kinked, smashed, or rusty. I've never had a problem like you're describing with the throttle. sounds like you've eliminated all possible causes aside from those that I mentioned. I'd visually check everything in the area of the pedal, while moving it down and up with your hand. If that all looks good, some lube in that cable might free it up.