Tremec TKX 5-Speed Conversion
- Thread starter CoronetDarter
- Start date
Derwud
Well-Known Member
I can put my car in 5th @45 MPH and roll on the gas, no bucking or hesitation, next thing I know I rolling past 70... I got them Torques..
CoronetDarter
Well-Known Member
There's so many different variables when determining rear end ratio, and the connecting rod length is one of them. The cam profile is a major consideration too; longer duration and tighter LSA moves the power band up the rpm range. Steeper gears get the engine into it's power band sooner.
That's the beauty of the Tremec, you can have your cake and eat it too. Blast around town with the steeper gears, and the overdrive calms it down on the freeway.
That's the beauty of the Tremec, you can have your cake and eat it too. Blast around town with the steeper gears, and the overdrive calms it down on the freeway.
I did my Tremec swap in 2021. Back then I had the 440/493 with about 10.17 compression and the Mopar '528 solid cam. It was a great performer and would accelerate in 5th from 1000 rpm quite easily. The longer stroke crank helped with torque. The cam went flat though so I had to pull it all apart.
I rebuilt the engine in 2022 using better pistons but with 9.8 compression. I re-used a Lunati cam I had here to save some cash. It is a bit wilder than the '528 was so it is not as peppy at low rpms. It does not pull clean from 1000 like before. It hesitates a bit until about 1500-1700 rpms...from there it starts to pull nicely.
Cam duration matters a lot.
The TKX uses a .68 5th gear, my TKO has a .64, close enough to not matter much. The 3.55 in 5th gear is 2.41 in the TKX and 2.27 in my TKO. Going to a 3.91 means a 2.65 with the TKX and 2.50 in a TKO.
Looking at the first gear overall ratio...
2.87 x 3.55 = 10.18
2.87 x 3.91 = 11.22.
Compare that to the overall ratio with a 727 automatic:
2.45 x 3.55 = 8.69
2.45 x 3.91 = 9.57.
I was tempted to use the 3.91 in my car but figured that 1st gear might feel too short. I had a 4 speed in my 75 Power Wagon where the 1st gear was real low. You could barely get halfway across an intersection before shifting. Also....
The longer the stroke of the engine, the less you need to rev it to make power.
I rebuilt the engine in 2022 using better pistons but with 9.8 compression. I re-used a Lunati cam I had here to save some cash. It is a bit wilder than the '528 was so it is not as peppy at low rpms. It does not pull clean from 1000 like before. It hesitates a bit until about 1500-1700 rpms...from there it starts to pull nicely.
Cam duration matters a lot.
The TKX uses a .68 5th gear, my TKO has a .64, close enough to not matter much. The 3.55 in 5th gear is 2.41 in the TKX and 2.27 in my TKO. Going to a 3.91 means a 2.65 with the TKX and 2.50 in a TKO.
Looking at the first gear overall ratio...
2.87 x 3.55 = 10.18
2.87 x 3.91 = 11.22.
Compare that to the overall ratio with a 727 automatic:
2.45 x 3.55 = 8.69
2.45 x 3.91 = 9.57.
I was tempted to use the 3.91 in my car but figured that 1st gear might feel too short. I had a 4 speed in my 75 Power Wagon where the 1st gear was real low. You could barely get halfway across an intersection before shifting. Also....
The longer the stroke of the engine, the less you need to rev it to make power.
Nobody knows how to heel and toe? Right heel on the brake and toe on the throttle.....let up on the clutch a bit and little bit of pressure on the throttle and go. Road racers learn it early on and it works for the hilly roads too. I like the line lock and the solenoid release idea too.
Derwud
Well-Known Member
That is how I do it..
one thing after the TKX/TKO upgrade is to ensure you have some new(er) tires
you’ll find yourself driving the car more frequently than you ever did prior
old/hard BFGs will spin on launches going uphill
watermelon
you’ll find yourself driving the car more frequently than you ever did prior
old/hard BFGs will spin on launches going uphill
watermelon
Phantomx
Well-Known Member
Taking off on a hill is easy in a v8 car with a heavy stock flywheel. While your foot is still on the brake, release the clutch pedal until you feel it start to grab. At that point you move your brake foot to the gas and take off. The car won’t roll back while you’re slipping the clutch, and when done properly you only slip it for a couple of seconds so there is no added wear on the clutch. Easy! No revving the **** out of it, slipping the clutch, or parking brake shenanigans. Just a smooth transition from stopped to moving. Find a hill and practice!
Travis..
Travis..
68_MOPAR_B_BODY
Member
I just finished the install of a used but new to me TKO 5 speed. (I have added the carpet since this photo was taken.)
Thank you to all that made this post so informative.
i can honestly say that his was by far the best upgrade i have done to this car. The car is way more responsive and fun to drive. I would have a hard time even considering an automatic in any of my projects in the future.
My apologies if this has already been talked about in a prior post. but i am having two minor issues.
1. the speedometer cable is leaking through the cable (not from the outside diameter of the aluminum adapter) and dripping on my headers and that's super annoying. i am assuming the o-ring seal is bad. if any of you have replaced the cable did you buy a new one from silver sport? or another company that has a better seal?
2. reverse lights. my car was a column shift automatic. what did you guys do the hook the reverse lights to the new transmission?
Thank for any and all information
Thank you to all that made this post so informative.
i can honestly say that his was by far the best upgrade i have done to this car. The car is way more responsive and fun to drive. I would have a hard time even considering an automatic in any of my projects in the future.
My apologies if this has already been talked about in a prior post. but i am having two minor issues.
1. the speedometer cable is leaking through the cable (not from the outside diameter of the aluminum adapter) and dripping on my headers and that's super annoying. i am assuming the o-ring seal is bad. if any of you have replaced the cable did you buy a new one from silver sport? or another company that has a better seal?
2. reverse lights. my car was a column shift automatic. what did you guys do the hook the reverse lights to the new transmission?
Thank for any and all information
1 Wild R/T
Well-Known Member
There is a switch on the drivers side mid case that's for the reverse lights...
The connector plug is available at the link below
Silver Sport Transmissions Wiring and Connections
The one you want is
ELA-00200
If your interested there is also a neutral switch that can be used to only allow the starter to crank when the transmission is in neutral... That connector is available at this link..
Ron Francis Wiring PG052 Ron Francis Wiring Neutral Safety Switch Connector Pigtails | Summit Racing
The switch for that is on the tail housing..
Never did like that neutral switch on a stick....heck, really liked not having it on my automatics too! 
Derwud
Well-Known Member
Plugged it and installed a Dakota Digital dash, no leaks...
CoronetDarter
Well-Known Member
I got my cable from SST. No leaks after about 18 months.
I agree.Never did like that neutral switch on a stick....heck, really liked not having it on my automatics too!
I thought about what was happening. You are pushing the clutch to disengage it with the engine off. All that force is pushing the crank forward and the thrust bearing is taking the load - DRY. That's fine until you go to start the engine and you have a dry thrust bearing against the crank while you are starting.
Nope. I disengaged mine. I don't want that extra wear.
Thing is....I've pulled engines apart that had been static for years and the bearings weren't dry. Surprised me the first time I pulled one apart that had been sitting for a very long time. How long does it take for 'all' the oil to drain off of a bearing? It doesn't happen over night nor does it happen after weeks or months.
True - I used the wrong word. I should have said there is no supply of oil to the bearing from the oil pump, so what oil is there has no pressure behind it and little ability to keep the two from touching.
1 Wild R/T
Well-Known Member
Accept this is a neutral switch... Not a clutch switch.. So the clutch doesn't need to be depressed..
Only reason I can see for not starting in neutral is a situation where the vehicle safety depends on the vehicle starting in gear... My 4x4 has a bypass switch for this exact possibility...
CoronetDarter
Well-Known Member
So you always start in neutral?
I do when driving a manual.
Similar threads
