Question about a Tremec TKO

[MaSnaka]

My first post-This looks like a great forum.

"My alternative is a toploader with a Hurst Competition Plus shifter and a Gear Vendors overdrive.  I'm comfortable with that option, but I'd kind of like to try a Tremec, since I've never had one before..."


Can you explain the overdrive in a 4 speed toploader?  I have a toploader and would love to have an overdrive or 5th gear for freeway cruising.  Is it a big deal?  My trans was rebuilt about 3-4 years ago.  3.73 rear gives me around 3500rpms at 70mph.

Thanks,
John

[jayb]

Welcome aboard, John!  I think the major drawback to a Gear Vendors overdrive is the cost; it is fairly expensive at around $2600.  You get a replacement tailshaft housing for the transmission, and the overdrive unit bolts onto that.  The overdrive is supposed to be good for 1800 HP or something, so you won't break it.  It comes with an electronic control module, a dash switch, and a foot switch like a Ford dimmer switch.  The dash switch lets you select automatic or manual operation.  There is also a speed sensor that goes between the end of the stock speedo cable and the cable that goes into the overdrive unit.  When in automatic mode the electronic module monitors the speed and switches the overdrive in and out automatically.  In manual mode this control is bypassed, and you turn the overdrive on and off with the foot switch.  Also, the overdrive cuts out whether in manual or automatic mode when the vehicle's speed drops down to 5 MPH or so.  So, if you are in overdrive and slow down for a stop, the overdrive will kick out automatically.

You will have to do a couple of other normal hot rodding things, like maybe modify the transmission crossmember (I had to slot a couple of mine to get the stock mounts to fit), run the wiring, etc.  You will also need to shorten the driveshaft and install the Gear Vendors yoke on your driveshaft, but any driveshaft shop can do that for you if you take the measurements.  For some cars, you may need to cut or clearance the floorpan to get the overdrive to fit.  Strangely, it fit really nice in the tunnel of my 69 Mach 1, but I had to cut the floor a little to make it fit my 64 Galaxie.

I have three Gear Vendors overdrives, and I really like them.  For this particular Mustang I'm really waffling on which way to go, the TKO or the GVOD.  I think it would be more expensive, but easier, to go the Gear Vendors route again...

[My427stang]

I think it would be more expensive, but easier, to go the Gear Vendors route again...

Jay, although I haven't done a GV, I can't think it would be easier.   The TKO may not shift like a Toploader, but the TKO is a no brainer. Just to put it in checklist form to make a point

- Stab the tranny, jack it up and make a chalk line on the cross brace and note where the front will hit under the radio
- Cut out the c-notch you just marked up with a cutoff wheel or plasma cutter
- Put a jack under the floor under the radio and move it, in one area where the vent is, maybe .250, or just beat with a hammer.  its not the whole floor, you just make room for the vent
- Install the new shifter on the box (no rails no rods, no adjustment, just 6 bolts and align the nub in the hole
- Install tranny & crossmember and space the mount to get driveline angle to stock or desired
- If the speedo cable isn't long enough, replace with AT cable

Stock length driveshaft, stock small input clutch fork and bell design, just needs a 26 spline input.

Its really a 1/2 to 3/4 day project to swap from one to the other.  Matter of fact, I did Charlie Logsdon's 57 Fairlane on a Sat morning in his garage without all my tools.

I think the ONLY issue you will have is that if it becomes a racer, you may want to spend more money inside the TKO to be able to shift it clutchless, but that just makes the parts more expensive, not more difficult

[jayb]

I guess I was thinking of the floor mods, Ross.  There won't be any with the GVOD and toploader, but I'll have to pull the carpet up and out of the way with the Tremec, and cut the holes.  I'm not going to leave open holes in the floor, so after installing the trans I'll have to fabricate some sheet metal shields and weld them in place over the holes.  Its not a big deal, but I'm trying to keep this particular car as "bolt-on" as possible.  The rest of the mods (driveshaft, clutch, etc.) I have to do in either case...

[My427stang]

There are no holes in the floor, just a notch in the channel that supports the floor, you never breach the interior. Admittedly, some guys don't want to cut a brace for originality, but its very minor

[jayb]

OK, thanks for the clarification, I didn't get that part.  If its only notching the original U-shaped brace that is spot welded to the floor, and not going into the interior, then its not a big deal.  Leaning back towards the Tremec again LOL!...

[MaSnaka]

JayB- Thanks for clarifying.  I am learning new things all the time.  I have more questions but will not hijack your thread and will post them in a different thread later.  I'm still recovering from my last project and am not ready to start another right now..

John

[sixty9cobra]

2200 or 2300 for the trans 100 for the shift handle, I had to get a new clutch, different speedo gear, different cross member. I could have bought a GV for the same price. But my topleader was tired so I went the TKO route.

[jayb]

Thanks for the info Harry.  My toploader needs to be gone through, so that would make the toploader/GVOD option more expensive for me than the Tremec.

[fe66comet]

Gear vendor weighs a ton added to the boat anchor top loader, you basically have a mid mount big block in there. Weight is HP no matter how you add it up, I am sold on the T56 for these reasons or you could go with a 7 speed salvage trans from a Corvette.......Jon

[jayb]

The Gear Vendors unit weighs 45 pounds, and the tailshaft housing is about 5 pounds heavier than the stock toploader tailshaft housing.  So a 50 pound adder using the GVOD. 

[plovett]

What rear gear does the Mustang have?  If it's high like a 3.00 or 3.25 you might consider a Richmond (non-overdrive) 5 speed.   Just a thought.

paulie

[jayb]

You know, I have a Richmond sitting on the shelf here, but I'm planning it for a different car.  I have a 9 inch to bolt into the Mustang I'm thinking about the Tremec for, and it has a 4.11 locker with factory 31 spline axles, so the Tremec or GVOD are attractive from that standpoint.

[machoneman]

IIRC Jay the Richmond 5-speed you have is the same one I have (in a SBF though) as we had chatted some years ago now about how the speedo bullet and helical speedo gear was actually from GM's M-21/M-22 tranny. Anyway......

Any thought to the relatively new Richmond 5-speed with overdrive?   It's the last one in the link below:

http://richmondgear.com/01fivespeed.html

[jayb]

Thanks for that link, Bob, I wasn't aware of that transmission.  And yes, I recall our conversation and I think we do have the same transmission, although now that I think of it, mine is actually a Doug Nash 5 speed, before Richmond got involved.  My problem with that trans for this particular project is I need to have the shifter come through the floor in the stock location and fit the stock console, and on my other '68 Mustang I had to cut the floor up pretty good to get the Long shifter to fit.  Hence my choice between a toploader with Hurst Competition Plus shifter or the Tremec.