tbear853

In another thread (dealing specifically with my install of a Hurst Billet shifter and modifications to that shifter and the addition of a "clutch pedal extension") I have made reference in several posts about how "old school" muscle car transmissions shifted smoother and with less effort.

January 1st the wife and I took the Mustang for a drive to Roanoke and then back home via Blue Ridge Parkway (dinner at Peaks of Otter) ... and I was enjoying the whole deal and was thinking about a bunch of threads I was reading the other night about shifting, knashing, grinding, nibbling, recommended lubes, etc .... and it occurred to me that really, our Mustang doesn't do any of that except when the trans is cold and a fairly quick (brisk like) 1-2 or 2-3 shift is attempted .... so we don't do that.

I did change the lube from factory fill to Mobil 1 ATF Synthetic back in the late Summer (car had maybe 23K) ...
... but I may try some Texaco Havoline Dex III/Merc conventional come Spring time.
I've read where some at Tremec suggest that the lesser slipperiness is thought to aid the synchro rings.

Once warmed up even just a little, it really shifts OK, but as I have said before, not like those old muscle car 4 speeds. I got to thinking about the "why". I had long ago with my '74 Toyota Celica GT and later my wife's '76 Celica GT attributed it in part to the internal shift mechanisms ...
... and I am sure that is a part of it as the '84 Mustang 4 spd and '86 Mustang 5 spd GTs the state had for us to use back in the day were also some notchy.

I have this habit, almost a double clutching but very abbreviated, not all the way out with the clutch but just enough that as I pass through neutral I pause as I ease up and press it back as then the engine RPM has dropped because I let off and engine thus slows the clutch disc and input shaft, trans slips into gear. It is a habit I've had for over 40 years. I tried it after an older cousin had explained it to me and I found it greatly eased shifting in my school bus and mail truck driving jobs. I guess it's become so second nature that's why I still do it when just driving, even in my wife's Forester 5 spd. and it's not as notchy as this Mustang if you are just pressing the clutch and pulling the stick and letting out on the clutch (but it too is stiffer when cold). Other times when not in a hurry, I'll just let up off the throttle and ease the trans into neutral and then push in the clutch and go from neutral to the desired gear, all in one movement however.

That's not to say I didn't throw what we called "power shifts" when running the car back in the day, that was fun too ... then. WOT, start preloading just before the shift, just fan the clutch in/out and the trans was in the next gear, no scrapes, no mechanical drama except tire slip (or so one hoped). But that was when I was a young toad and didn't mind yanking a trans to do a clutch change or replace a brass ring or maybe a U-joints on a Saturday afternoon. But those old muscle cars big 4 speeds were smooth even in everyday driving, just push in clutch and move stick (Hurst C+ in all mine) and you were in next gear, no serious notchiness that I ever felt. There was no need to pause in neutral, but when just cruising I still sometimes did after acquiring the habit I'm sure.

Those old transmissions had a shifter bolted on, three rods running up to the side cover and levers, and alignment was in neutral with a 1/4" L shaped pin (still have mine), and inside the side cover were forks that road on sliders ..... easy to work on they were! But as heavy (that Dart's NP A-833 4 speed was a monster, way heavier ... and stronger .... than a Muncie, and is still the heaviest 4 speed put in a pass car) as they were, as strong as they were, they shifted so sweetly. I never owned a Ford with a T&C top loader, but a buddy who had a couple 70 Torinos with 429 SCJs did and they likewise, shifted just great. The only car I drove back then that I recall shifting badly was a Chevelle with a OEM Muncie shifter .... but that was a crap shifter on a good day.

So .... to continue, I came home and did some math. Mustang's TR3650 ratios 3.38 / 2.00 / 1.32 / 1.00 / 0.62 so if you take it to say 6000 in each gear:
1-2 drops rpm to 3550,
2-3 drops rpm to 3960,
3-4 drops rpm to 4545,
4-5 drops rpm to 3720.

New Process A-833 4spd as in my '69 Dart Swinger 340 ratios: 2.66 / 1.91 / 1.39 / 1.00 so if you took that one to 6000 in each gear:
1-2 drops rpm to 4308,
2-3 drops rpm to 4366,
3-4 drops rpm to 4316.

M-21 or M-22 Muncies as in my GTO or Chevelle both had ratios 2.20 / 1.64 / 1.28 / 1.00 so if you took those to the same 6000 in each gear:
1-2 drops rpm to 4472,
2-3 drops rpm to 4682,
3-4 drops rpm to 4687.

Even the wider ratio M-20 with it's 2.52 / 1.88 / 1.46 / 1.00 ratios:
1-2 drops rpm to 4476,
2-3 drops rpm to 4659,
3-4 drops rpm to 4109.

So I see where this Mustang's TR3650 wider spaced ratios (I knew it was a wider ratio spread, just never done the math) would make life harder on the synchro's life as they are forced to slow that spinning "input gear train" (includes: input shaft / gear / countershaft gear set / any intermediate gears on MS / clutch disc / and any lube windage effects) at a much faster rate to drop those extra RPMs on an upshift .... especially on that 1-2 and 2-3 upshift .... and why it seems so that it likes my "abbreviated double clutch" upshifts.

Likewise, on downshifts, the synchros are asked to speed up the "input gear train" speed to match the higher flywheel speed that desired lower gear will call for, hence "
heel and toing" (in a hurry) or simple double clutch with a throttle tap between gear selections (when not so much in a hurry or not braking at same time).

Getting back to upshifts, take my '69 Dart above at 6000 (I usually shifted it around 5500 if in "anger" in real life), those synchro had to scrub 1692 rpm off the "input gear train" speed on that fast 1-2 shift ...
... while this Mustang's synchro has to scrub some 2450 rpms off the "input gear train" speed in the same time frame if that same 1-2 WOT powershift is attempted.
That's a bit more work .... a "lot more" if one were to compute the change in the inertia involved with the whole "input gear train".
It also occurred to me that besides all that, the 5 speed has even more mass associated with that extra gear included in that "input gear train".

I know and practice heel and toe in down shifting if doing so to slow in a hurry, but sometimes I just let up on the gas and gently apply the brakes and when road speed brings RPM down near 1K and I'll find a lower gear if making a turn or stopping, etc. If someone pulls out in front of me or an animal jumps out, I likely just clutch and brake hard and look for steering alternatives if viable and consider a lower gear selection.

So after having given all this some thought and putting it to paper (so to speak) ....
.... I am hereby reconciled with the simple truth that these internal shift rail 5 speed and 6 speed transmissions (3 rails involved here) with wide ratio spreads to chase higher MPG while still offering decent performance will never shift like the old Muscle cars did .... "no way and no how" ...
... but then I'm not 18-22 anymore am I?

Nope, I am 60 now and while I still enjoy rowing gears and getting involved in my driving or riding (motorcycles) .... I no longer care about WOT full on powershifts .... but I still want my stuff "right".

Lime GT

I believe the trans shift problems are created simply because the shifter is attached to the trans as well as the chassis. If the trans shifter was attached solely to the transmission the shifter would not twist as the engine/trans torques. This would allow the single shift rod to stay in its proper alignment under load with the engine/trans combo and allow the shift gates to stay true with the transmission. Just my thoughts./

AlsCobra

I'm pretty sure the MGW shifter takes care of that problem. It's still a poor trans but that is part of the issue for sure.

Supra

My TR3650 was one of the best shifting transmissions i've ever had after swapping the fluid over to GM synchromesh part # 89021808

tbear853

Quote:

Originally Posted by Supra

My TR3650 was one of the best shifting transmissions i've ever had after swapping the fluid over to GM synchromesh part # 89021808

I have been mightily tempted to do just that, but first I wanted to try Texaco Dexron III conventional.

To update this thread from my point of view ......

OK, today is April 5th, it's into Spring .... and where ever I looked this week I could not find anyone who sells Texaco Havoline Dexron III / Mercon conventional transmission fluid. So I brought home a gallon of Advance Auto Parts branded Dex/Mec with every intention of draining the 3 plus quarts of 1000 mile old used Mobile 1 Multi Trans Synthetic that is suitable for Mercon V, etc .... and after a good drain, installing 3.2 qts of this .... but I didn't.

Instead ....
.... I got the car up on 4 ramps (pulled front up on two, jacked each rear and set a ramp under) so I could get under it and let the transmission drain into a meticulously clean drain pan (which I then poored into a spotlessly clean former oil jug and labeled with current contents for possible future use should this Dex/Merc not do so well).

Then just as I was getting prepped to open the new jug ..... when suddenly I recalled a box of mixed quarts of miscellaneous transmission fluid up on a shelf, been there a few years. I took a look, what was in the box was 14 quarts, some Texaco, some Amalie ....
.... and all marked "Mercon / Dexron III".
http://i220.photobucket.com/albums/d...ps20b18461.jpg
So then, using a hand pump ....
http://thumbs1.ebaystatic.com/d/l225...c4Ra_KDAww.jpg
.... and pouring the fluid into a measuring cup to the 16 oz line (32 ozs is a quart) each time ....
http://ecx.images-amazon.com/images/...4L._SX425_.jpg
.... I installed the drain plug and removed the fill plug and pumped just a dribble less than 3 quarts and 7 ounces (call it 3.2 quarts) of slightly aged (est left over from mid '90s) Texaco Havoline Mercon / Dexron III ATF into her.
http://i220.photobucket.com/albums/d...ps236e63fd.jpg

I then took "Wife Unit" out for supper, and at first,it seemed as if there was no change during the 15 mile drive to town as I slowed and tried to shift quickly a few times. Let car sit while we ate, maybe an hour, them synchros soaking in the Dex III/Merc juices. Then we headed home, and even though I don't normally shift fast, tonight I tried 1-2 and 2-3 and even 3-4 pretty briskly, and no question, it shifts some better. There were absolutely no crunches or scrapes .... and while the rails and detents still make it feel "notchy" on a gear change (that'll never ever go away) .... for the first time since I bought this car last summer it feels like you could get a good run out of it in a 1/4.

Last comment is maybe it's "just me", but it does seem as if maybe there's a smidgeon more noise coming from the transmission .... but I'm not sure.

fdjizm

My WOTBOX solved all my fast shifting problems, runs like butter now.
WOTBOX cuts the spark as soon as I kick the clutch for a millisecond so I shift without torque on the input shaft and I've been loving it for 3 yearsnow.

tbear853

I had never heard of such a thing. We used to do WOT shifts .... and they are scary when missed because they can be very expen$ive when missed. This would certainly remove much of that.

I can see how with all the sensors it attaches to, it knows when you are clutching under WOT, so it wakes up and does it's thing of killing spark from 25 up to 700 milliseconds .... almost seems like "cheating" compared to the old days.

I ever get the urge to go play at the drag strip, this is something I'd have on my list. It's certainly cheap enough.

Update here 7 years later in 2021. After much fiddling with it, I know I'll never get it seemless like those old transmissions due to the fact that the TR3650 has shift rails with notches milled in them that pass spring loaded ***** creating strong detents for each gear, 1-5 and reverse ... and neutral. That will never change, and my Hurst now has 3" of stroke (stock was 4", stock Hurst was a hair over 2" but I added an extension that adds 1-3/4" to the stick) 3rd to 4th through neutral as it passes out of a detent, then through a detent, then drops into a detent. Those old transmissions did not do all that. I do think the Bondurant clutch pedal extension and the SS braided clutch line helped as did Dex III/Merc fluid ...
... but finding and removing that old black rolled up old carpet mat from under the clutch help a huge bit too.