Comparing manual trans options - variables other than gear ratios?
If we put aside the number of gears and their ratios, which ones compare favorably or unfavorably for the following variables (or anything else that I didn't think of):
Group 1
Strength
Longevity/durability
Parts availability
Cost to purchase
Complexity of installation
Driveline energy loss
Noise
Group 2
Mass
Driving experience/shifter feel/clutch engagement
Unique problems??
The only M/T I have any experience with is the A833.
It hits all the bases in Group 1 favorably. As for Group 2
1) mass;
the A833 is heavy. But the good news is that the weight is almost all in the iron cases. But you can change that by stuffing the Gears into the F-body case and alloy tail, which is what I did for about 4 years. Eventually I installed a Passon alloy case, with a GVod alloy tail and a Passon alloy side-cover. That was in 2004. Then I quit worrying.
The GVod is about 23 pounds IIRC, and the rest is down to 85 IIRC, for a total now of 108..... verses 135 w/o the gvod in the prior configuration ..... IIRC. So now I have lightweight 4+1 speed, with splitting capabilities, and a nice Progressive set of ratios..
Typically I shift it 1-2-3-3od-4od and the ratios go like this;
3.09-1.92-1.40-1.09-.78od with progressive splits of
.62-.73-.78-.715
2) shifter feel/clutch engagement
Because the GVod was only available with the long-tail, I had to convert the Commando box to a long shaft.
The whole thing fits into the tunnel with what I consider modest adjustments; just a few hammer blows, and I dropped the tail about .25 inch, as an anti-rattle precaution, and installed an engine torque-strap for the same reason.
Then I had to deal with the shifter pads. One of the the front bolt-bosses had to be partly cut off for X-member clearance. It's alloy so zing, off it went. That left me with just the rear pad. I could have mounted the shifter on a fabbed plate and stuffed it into the factory opening, no problem. But as you may know, that location was a compromise for the bench seat and IMO, always sucked from day-one. Since I had installed buckets, I moved the opening back about seven inches, then raised the shifter up as high s I dared.
2b) I installed an old Mr.Gasket "Bang!" Shifter circa 1971, which has a very short straight handle, Ima guessing about 7 inches. I angled it so that it fell to hand. I mean, it's right there by my thigh; no more knuckles in the dash. Finally I fabbed up some stout tubular shift-rods using some cut-off factory ends with metal bushings, that I had laying around.
2c) By this time, I had already installed a CenterForce diaphragm clutch. But I really did not like the CF-II disc, so I stuck a factory 340 disc in there, from the Direct-Connection catalog. It turns out that these 340 discs are not strong enough for my engine, and keep either spitting out springs or fracturing the hub, or both, lol. I'm on the third or fourth one in about 80,000 miles. Seventeen minutes is my record for dropping that box.
2d) The 340 disc has a very nice feel to it, but to help it live, I shimmed the CF PP off the flywheel about .060.(a washer width). This allows a tiny bit of slip at low-rpm, and now, I can dump it and go. However, by about 3000rpm, the flyweights are locked up solid. My 340 discs are now lasting much longer.
2e) I slick-shifted Second and Third, so the heavy A833 gears now shift like lightning even at 7200.
3) Driving experience
with 3.55s in the back, the driving experience is, IMO, unparalleled. My 367 is pretty stout, and the trans always has the right gear at the ready. Looking at the Roadgears, the ratios look like this
10.97-6.82-4.97-3.88-.78od; with splits of
.62-.73-.78-.715, notice the progressively shorter splits, and the nice.715 drop into cruiser gear. There is always a "right" gear
3b) But Like I said, my 367 is stout. I run alloy heads , currently at 11/1 Scr, which gets me 180 psi on the compression tester. She has run more pressure under a different iteration. This really helps with the bottom-end. Actually, it has the strongest bottom-end by far, that I have ever run (SBMs only)..She is so much fun.
4) Unique problems??
As for the GVod; she has a few caveats.
1) you must never back up with the unit engaged; (it breaks the guts somehow)
2) With the GV provided, electronic-shift-module; it shifts pretty slowly. (Without it, wired direct to battery voltage(thru a switch of course) it shifts just about instantly, at WOT, barking the tires on every split on the way to 93MPH in the Eighth, with BFG 325/50-15 DRs.)
3) the Unit can be in-shifted under full-power; but when out-shifting, the power has to be eased/cut. (With a clutch this is automatically solved.)
All of these have been easy to overcome.
As for the Commando guts; I have not been able to break them. I run 50/50 Dextron-II and 85/90EP
Other;
1) The Bang shifter is as awesome today as it was in 1971. With the tubular rods I have not missed a shift since 2004. With the other mods I made, she has NEVER needed to have the Neutral-gate adjusted, not once since installed in 2004.
2) Trying to adjust the Pedal free-play with the factory TO fork system, and TTI headers, was, initially, a PITA. But I soon solved that.
3) To install the GVod, I had to cut out the TTI crossover. At first I missed the bottom-end torque. But the Commando gearset, and a new tune, solved that and more besides.
Finally;
As much as I love this combo; If I was starting out from scratch, with no transmission at all;
1) I would like the OD to be inside the main box, and NOT a planetary type.
2) I would like the same or extremely similar gear progression.
3) I would detune my engine with a solid FTH cam of at least one size smaller, and run 3.23s.
4) I would install a spreadbore carb and target hi 20s/low 30s steady-state fuel economy.
5) Aw who am I kidding; at my age (69),
I'd probably install an A500LU/a3500TC, and 3.23s. Lol
. BadaBoom!
