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6-Speed TF-727 Gearbox


Behind a custom built high powered Hemi, you've got to have a transmission capable of handling it. I currently have the tune at a very conservative 660hp and 632lb-ft of torque but this engine can be tweaked with just the "turn of a screw". With laptop tuning, bigger injectors and a few thousand dollars, this big headed elephant can make 1,000hp+ with plenty more left in it. These figures are of course natural aspirated (NA) to "non car people", for lack of a better phrase, that means without a supercharger or turbo(s), can you imagine the hp if I added those!? Impressive stuff. 

When you're talking that kind of hp (even 660hp / 530rwhp) reliability, ease and shift speed all play a massive part in drive-ability and enjoyment. I want something that can handle big hp without frying clutches and slower shift times. I decided to stick with the original Torqueflite-727 transmission (built for war) working with a one of 5 Gear Vendors "Autoshift Sequencer" unit on the back giving it an Overdrive (OD). 

My Gear Vendors (Autoshift Sequencer) unit is different to the "standard control box" units where-as you do not need to shift OUT of OD when you shift the shifter up, resulting in a cleaner quick shift. I have used both. I originally got the stock box that comes with the kit. With the stock box, once you shift the shifter up, you have to click off the OD INSTANTLY after the gear changes (within a split second), it's messy and hard to time perfectly every time. 

I complained about this "jolty delay" and was supposed to get a replacement box. Long story short, with some miscommunication between Year One and Gear Vendors, I was accidentally sent a newly released "Autoshift Sequencer" unit not for the general public. According to the President of Gear Vendors (Rick Johnson) whom I speak to, only 5-6 cars in the world have this. Joe Rogan and his 1970 'Cuda ("Sic Fish"), Kenny Wayne Shepard and his "General Lee", a 1967 custom Dodge Charger, I believe Jay Leno has 1, a custom hot rod and Lucy, so she is in good company.

What is Gear Vendors - In short, it's a bolt on OD torque multiplier unit. The final OD ratio is 0.78:1. Take my existing rear gear multiplied by 0.78 (ie; 3.55 X 0.78 = 2.76). So my Dodge now runs like a car with 2.76:1 gears. So good for fuel consumption! However, that's just the start, it's not just an OD unit, the torque multiplication is mind blowing. Talk about tree stump pulling, tyre barking, launch power. 

The Gear Vendors units give you the ability to split each of the 3 gears, making it a 6-Speed. This is called "gear splitting". This give me 6 x short gear ratios rather than 3 long ratios where the rpms drop way down, typical in most automatics. This keeps the engine in the power band and equals faster acceleration and 1/4 mile type performance. My 3.55:1 gears pull like a I have 8.70:1 gears in 1st, yes, 8.70 gears! In 1st-Over, it's like I have 6.78:1 gears and so on. The performance and sound of the engine is tremendous as it goes through 6 close ratio shifts. You are in each gear half the time so the car is not only faster but it also feels and sounds much faster, 28.6% faster in fact.

Combined with the Gear Vendors, race bands, clutch packs and HD sprag, I now run a Full Manual Valve Body in my TF-727, meaning I have to shift with the shifter up or down for every gear. When I come to a stop, I have to shift back to first and then shift up to 2nd, then 3rd, etc. If I stop in 4th, it takes off in 4th. It's like a clutch-less manual, just easier, faster, smoother and just as fun (especially with a Hurst Pistol Grip controlling the ratchet shifter!). The best of both an automatic and manual combined. 

Another cool function about Gear Vendors is, it has a function called "Auto-Launch". This allows the transmission to shift automatically into 1st-Over based on the predetermined gear ratio. This only happens in the 1st to 1st-Over shift and with 8.70 gears, it helps by giving you time to keep the car heading straight! haha. It is a very unique system that does take some getting used to, especially with a manual valve body and up/down ratchet shifter with new gear display. Before long, it's like riding a bike and is super fun and a nice feature that compliments the rest of the cars custom touches. I explain below, how all this works in detail going through the gear splitting operation etc.


My Gear Vendors "Autoshift Sequencer" Shifting Explained:

1st Gear (1st) - Throttle and immediately hit button on Shifter, "Auto-Launch" engaged.

*Gear Vendors Auto-Shifts at correct RPM, OD engaged*

1st-Over (2nd) - Throttle, shift Shifter Up.

*Transmission shifts up, OD disengages instantly upon shift*

2nd Gear (3rd) - Throttle, hit button on Shifter.

*Gear Vendors shifts up, OD Engaged*

2nd-Over (4th) - Throttle, shift Shifter Up.

*Transmission shifts up, OD disengages instantly upon shift*

3rd Gear (5th) - Throttle, hit button on Shifter.

*Gear Vendors shifts up, OD Engaged*

3rd-Over (6th) 

You can gear split any time and chose any of the 6 ratios. Examples; you are cruising in 2nd gear and want a little less rpm, hit the shifter button to go into 2nd-Over (4th). Maybe you're stuck in traffic and 1st-Gear is not quite right and 2nd gear is too much, hit the button and shift between to 1st-Over. You could also be in 3rd-Gear (5th) and shifting down to 2nd-Gear (3rd) is too much, shift down and hit the button for 2nd-Over (4th) to be in the middle. You can also drive normally through the gears with the shifter, shifting up from 1st, to 2nd, to 3rd and when you want the basic OD, hit the button for highway cruising. It's super flexible. I love it!

The rebuilt heavy duty Torqueflite-727 transmission (TF-727). 

It had a full race rebuild with custom bands, clutch, drum work etc.

It now runs a full manual valave body (FMVB) for clutchless manual shifts.

The custom spec TCS 10"  converter. The transmission builder (Chuck Mann) liaised with the Hemi builder to make sure the torque, hp and rear end gears were perfect. In short, this converter is perfectly matched for my drivetrain and car.

The TF-727 with the Gear Vendors unit bolted to it.

The Gear Vendors unit. These are super stout pieces. The guts are forged from a single piece. They are capable of handling over 2,000hp and are in 7 second drag cars. Plenty for my application. 

Serial number.

The brains of the OD. The "Autoshift Sequencer" unit.

The custom built original Hurst "Pistol Grip" shifter controlling a Hurst Promatic-2 ratchet shifter. To operate OD or control the gear splitting, simply click the button on top of the pistol grip (in any gear).

In the top right hand corner of the dash instrument cluster, you'll notice a custom made display piece with a Red light (Turns Green when OD is engaged). This sits perfectly in my line of site and at a glance tells me when I'm in our out of OD (that's easy) but more importantly, when I'm in a gear split, ie: 2nd-Over.  Makes for a great combo with the Gear Display "[2]" to it's left.

All these nice custom "toys / gadgets" while still managing to appear pretty factory. Perfect!