Anyone running the new Tremec TKX 5 speed?

[Mbeef61]

Curious if anyone is running the TKX 5 speed. Considering it over the Magnum 6 speed.

Just curious how the install went, how the ratios are, aftermarket parts etc.

I just don't know if I REALLY need a 6th gear.

PROS for TKX: cheaper up front, less tunnel work, lighter weight.
PROS for t56 Mag: Stronger, more aftermarket support

[AcampoDave]

Their website says available with 3 different ratios but only gives 2 of them. I am no tranny expert, but I wonder what kind of drivetrain set-up you have, in what kind of truck and how would you be driving that truck? I did a lot of reading up on ratios when I swapped my 3 ring Saginaw for a Muncie M22Z and went from a 2.76 rear with a 3.50 first to a 3.08 rear and a 2.98 first. I don't remember the figures for the other gears now but the Saginaw had a wierd spread 1st and 2nd were close and 3rd and 4th were wide. The Muncie is nice with a rythmic winding of the motor between shifts. I feel that to be super important in a street rod tranny. I'm not into racing or burnouts and stuff so I wanted a good all around driving set-up. I get that people like a torquey first gear, but shifting into second before I've even cleared the midlle of an intersection just isn't me. (Which is exactly what happened when I combined the 3.50 first of the Saginaw with the 3.08 rear)

[Mbeef61]

I have an ls1 being rebuilt. Might even go 383 with it. Doing big disc brakes and qa1 coilovers. It’s will be spirited driving. Playing around. Nothing professional but high quality and performance oriented.

It has 3.73 gears but I will be redoing the rearend so I’m open to gear choice. Maybe 3.73 again. Maybe 4.10.

It had a 3 line Saginaw before with 3.11 first.

The tkx does come in 3 ratios. A close and wide. I believe the close has 2 5th gear options

[AcampoDave]

Again, I'm no expert but I do enjoy this topic. My first inclination with set up you described would be the close ratio and the deeper overdrive.

[mongocanfly]

I've got a buddy with a t56...he loves it..hes running 3.90 rear gears with it and I think a 27-28in tire
I have a tr6060 for mine, if i ever get around to building it..
You can use one of the many rpm calculators to help pick a rear gear..based on your tire size and the rpm range you want for cruze rpms..
http://www.csgnetwork.com/multirpmcalc.html

[crazy longhorn]

I love gears! The rear diff is 3.42, with a 6 spd Richmond trans.1st is 3.28....yes, she dances hard on the go......the rest of the gears 2-5 are about on line with a a close ratio Muncie. OD is .76. She was really jumpy in town with 4.10 gears in the rear, but IMO, very livable with the 3.42 gears. In OD, the old truck will cruise @ 3000 rpms @ 100 mph. I dont feel that i need the double OD box, that the T-56 has, but if you run the box that has a low 1st, & maybe the spread gears for you app, you may be happy. Longhorn

[blazer2007]

brings back memory's , I had a Doug Nash 5 sp. in my Vette. Close ratio first 4 gears and 5 th. was one to one . Sure was fun. I beat the hell out of it and it just kept going.

[Tom]

Doesn't seem much different then a TKO600

[burnin oil]

Just as a thought here. If you live in an area with alot of hills or spend a decent amount of time in stop and go traffic then that slightly lower first can be really nice. My 72 has 4.10s with a really healthy cam riding on 33s. I would take off in first gear that 6.54:1 in bumper to bumper traffic even though second gear was 3.57. The clutch thanked me all the time for that decision.

[typerr]

Originally Posted by Mbeef61

Curious if anyone is running the TKX 5 speed. Considering it over the Magnum 6 speed.

Just curious how the install went, how the ratios are, aftermarket parts etc.

I just don't know if I REALLY need a 6th gear.

PROS for TKX: cheaper up front, less tunnel work, lighter weight.
PROS for t56 Mag: Stronger, more aftermarket support

I'm currently running a T-5 but have just purchased a 500 hp 396 stroker so I'll also be upgrading the transmission to a TKX. Biggest issue I have found is the lack of aftermarket support. Nobody currently makes a mid-mount shifter and only American Powertrain makes an aftermarket shifter for the standard location. I have a bench seat and currently run an S-10 tailhousing with my T-5 to move the shifter forward. I bought the AP shifter with a 3" offset to move the shifter as far forward as possible but it will be tight. Other than that it should be an easy swap. The TKX is about an inch shorter than my T-5 but I'm moving the engine back so a new driveshaft was going to be required anyway. I'll report anything else I find when I start the swap in a couple weeks.

[Mbeef61]

TypeRR that would be good info. That was my fear. Being so new the market hasn’t caught up and the TKO series isn’t as performance oriented in the same league as a t56 six speed. The aftermarket support for t56 is massive.

Will you be able to use the same crossmember then?

[typerr]

Originally Posted by Mbeef61

TypeRR that would be good info. That was my fear. Being so new the market hasn’t caught up and the TKO series isn’t as performance oriented in the same league as a t56 six speed. The aftermarket support for t56 is massive.

Will you be able to use the same crossmember then?

I think the TKX will catch up with the T56 but it will take a while and Covid isn't helping.

When I installed my T-5 I used the original truck bellhousing and hung the T-5 off the back like the old 3-speed and didn't run an additional crossmember. It hasn't been an issue with my mild stock 350 but with the new motor I'll run a conventional bellhousing and rear mount.

[Tom]

Originally Posted by Mbeef61

TKO series isn’t as performance oriented in the same league as a t56 six speed.

I don't know about that... The T56 came oem in cars hence its massive popularity.

[SIXTY9]

Have you checked out Silver Sport Transmissions?(shiftsst.com) I got my TKO 5 speed from them and they installed the shifter in the M22 location for me. Just for info I am running it in a 69 C10 with bucket seats.

[SidsChopShop]

I installed a TKO600 in my daily driver '66 last December and it has been flawless. I had my choice of either the new TKX or one of the last TKO's as they were being phased out for the newer trans. I ultimately picked the TKO because of two reasons. The first being the known history and durability of them versus the new model trans and at the time, TKX wasn't compatible with the mid-shift position since I was keeping my bench seat.

Since my truck was a factory 3 speed, I used the original GM cast iron bell housing and mechanical clutch linkage but made my own trans crossmember for the tail to rest on. It was a very straight forward and simple install.
For specs my trans has 2.87 first gear and .64 overdrive. 4:11 rear end with 28.5" tall tires. It'll cruise all day 1900 rpm at 70 mph

So far the TKO has 10,000 miles on it (yes true daily driver) and also drove this years Hot Rod Power Tour. It has been nothing but flawless and well worth the cost. I don't see how the TKX wouldn't be any different.

[LS short box]

I've used both the TKO 600 and T56 Magnum on a couple of LS swaps. The TKO 600 was behind a LS3 in a 73 Camaro. 3.73 gears. 285/40 18" tires. Great combo. I would have to say the TKO did not shift as nice as the magnum. A bit notchy.
The magnum was in my 68 C10. Small cam LS6. 285/40 20" rear tires. 4:10 gears First gear was kind of a waste of time. Easily could start from a stop from second gear. On the other end 5th at 60 mph was great. 70-75 mph on the freeway was perfect. The stock shifter on the magnum was a bit more direct and less notchy IMO.
Tough call on either. Can't go wrong with either. The TKX is cool since it most likely fit without cutting the tunnel.
Good luck with your swap.

[Mbeef61]

Originally Posted by LS short box

I've used both the TKO 600 and T56 Magnum on a couple of LS swaps. The TKO 600 was behind a LS3 in a 73 Camaro. 3.73 gears. 285/40 18" tires. Great combo. I would have to say the TKO did not shift as nice as the magnum. A bit notchy.
The magnum was in my 68 C10. Small cam LS6. 285/40 20" rear tires. 4:10 gears First gear was kind of a waste of time. Easily could start from a stop from second gear. On the other end 5th at 60 mph was great. 70-75 mph on the freeway was perfect. The stock shifter on the magnum was a bit more direct and less notchy IMO.
Tough call on either. Can't go wrong with either. The TKX is cool since it most likely fit without cutting the tunnel.
Good luck with your swap.

This is great info. Yeah I have heard TKO lacked the performance shifting that a t56 has. I heard that is one of the biggest things they changed in the TKX was to shift more like the magnum. Do you use 6th gear really? On paper it seems like the TKX is like a smaller t56 5 speed. I am leaving my 3.73 gears in until I install everything and drive it and then will be doing axles, Truetrac and whatever gear set I decide. Maybe 3.73 again or higher/lower.

[Mbeef61]

Originally Posted by SIXTY9

Have you checked out Silver Sport Transmissions?(shiftsst.com) I got my TKO 5 speed from them and they installed the shifter in the M22 location for me. Just for info I am running it in a 69 C10 with bucket seats.

Yeah I have talked to 3-4 companies, them being one of them. Waiting to see if there are any Black Friday deals on anything

[Mbeef61]

Originally Posted by SidsChopShop

I installed a TKO600 in my daily driver '66 last December and it has been flawless. I had my choice of either the new TKX or one of the last TKO's as they were being phased out for the newer trans. I ultimately picked the TKO because of two reasons. The first being the known history and durability of them versus the new model trans and at the time, TKX wasn't compatible with the mid-shift position since I was keeping my bench seat.

Since my truck was a factory 3 speed, I used the original GM cast iron bell housing and mechanical clutch linkage but made my own trans crossmember for the tail to rest on. It was a very straight forward and simple install.
For specs my trans has 2.87 first gear and .64 overdrive. 4:11 rear end with 28.5" tall tires. It'll cruise all day 1900 rpm at 70 mph

So far the TKO has 10,000 miles on it (yes true daily driver) and also drove this years Hot Rod Power Tour. It has been nothing but flawless and well worth the cost. I don't see how the TKX wouldn't be any different.

How is your first gear? Work ok with 4:11 gears? Mine had a 4 speed Muncie in it before so I’ll have to run some measurements to see where the shifter would land. I’m open to seats. I have bench but really like shorty buckets also

[SidsChopShop]

Originally Posted by Mbeef61

How is your first gear? Work ok with 4:11 gears? Mine had a 4 speed Muncie in it before so I’ll have to run some measurements to see where the shifter would land. I’m open to seats. I have bench but really like shorty buckets also

First gear works quite well and you can actually use it as a gear and accelerate to a decent speed at takeoff compared to my old 3 speed. If you don't wind it out and short shift into second, the gear ratios are pretty close together. I am able to take off in second gear as well but majority of time I'll throw it in first.

[typerr]

Originally Posted by typerr

Nobody currently makes a mid-mount shifter and only American Powertrain makes an aftermarket shifter for the standard location.

An update! Silver Sport Transmissions is now in production and shipping a mid-mount shifter kit for the TKX! Perfect for those of us keeping our bench seats. Mine is ordered and should be here in a few days.

[Warrens69GMC]

Originally Posted by typerr

An update! Silver Sport Transmissions is now in production and shipping a mid-mount shifter kit for the TKX! Perfect for those of us keeping our bench seats. Mine is ordered and should be here in a few days.

Any update?

[typerr]

Originally Posted by Warrens69GMC

Any update?

As a matter of fact I finally have the engine and transmission mounted in the truck. The Silver Sport mid shift kit was a relatively simple install although you do need to take the tailhousing off the TKX and shorten a pair of shafts. Only issue I've come across is the angle of the engine/trans relative to the frame is about 5-6 degrees to get adequate clearance between the top of the trans and my low hump floor. I may live with it since I'm doing fuel injection anyway or may go high hump.

[mjs94080]

Originally Posted by typerr

As a matter of fact I finally have the engine and transmission mounted in the truck. The Silver Sport mid shift kit was a relatively simple install although you do need to take the tailhousing off the TKX and shorten a pair of shafts. Only issue I've come across is the angle of the engine/trans relative to the frame is about 5-6 degrees to get adequate clearance between the top of the trans and my low hump floor. I may live with it since I'm doing fuel injection anyway or may go high hump.

Is it better to have it at mid shift? I have a 66' C10 with bench seats. I'm told that it's just a matter if I want my shift closer to the dash or to the seat. Before I order TKX I'm told that I have to tell them where I want my shifter before they ship it out to me.

[MySons68C20]

Originally Posted by mjs94080

Is it better to have it at mid shift? I have a 66' C10 with bench seats. I'm told that it's just a matter if I want my shift closer to the dash or to the seat. Before I order TKX I'm told that I have to tell them where I want my shifter before they ship it out to me.

Depends how tall you are & how long your arms are
I told Silver Sport my combo and it came out great.