Q: What signals does it need from the engine?
A: TPS and RPM
Q: What yoke does it use?
A: TH400/4L80e Slip yoke
Q: What shifter do I need to operate the transmission?
A: Any standard 4 speed automatic forward pattern shifter.
Q: What do I need to know to set up the computer?
A: You will have to answer a few simple questions like Rear Gear Ratio, Max Engine RPM, Tire Height, Number of Cylinder, Tach Type, and TPS set up.
Q: How does the transmission know when to go into manual shifting mode?
A: A toggle switch will have to be wired in utilizing a 12v source.
Q: What are the dimensions of the 6x six speed?
A: Overall dimensions are:
Q: Do I have to use the paddle shifter?
A: No. You can use just a floor shifter and the transmission will shift automatically or you can wire up your own two-button set to manual up shift and down shift the forward gears.
Q: What is the converter bolt pattern on the converters for the 6x six speed?
A: TCI® Torque Converters have both narrow (10.75”) and wide GM (11.5”) bolt patterns.
Q: Does the 6x use a lock up style converter?
A: Yes
Q: Is this the same as a 6L80e?
A: No. This is a transmission that TCI® has designed using a 4L80E as the base model.
Q: Can this transmission operate with a factory computer or without the TCI® computer?
A: No. The 6x transmission has to use our TCI® Transmission Control Unit for proper operation.
Q: What engines will this transmission bolt up to?
A: The standard 6x comes with the standard GM bellhousing bolt pattern. However we have adapter bellhousings to go to Ford: Small block, Big Block, and Modular engines, as well as Chrysler: Small Block, Big Block, and Hemi engines.
Q: What starter do I use for a Chrysler or Ford application?
A: Any stock or aftermarket starter will work.
Q: Can I shift through all six gears with my floor shifter?
A: No, the manual valve, and valve body only work off of 4 positions. Shifting manually with a floor shift would only allow gears 1,3 and 5.
Q: Will this system work with my FAST™ XFI™ unit?
A: Yes, this system incorporates 2 CAN connectors that simply plug into the FAST™ "XFI link".
Q: Can the gear ratios be changed?
A: Yes, but the current ratios that we have give the transmission the best spread between shifts.
Q: Will this help my fuel efficiency vs. my TH-400?
A: Yes, when using any 3 speed transmission high gear is 1:1 with a non lock- up converter, whereas the 6x has a high gear of .75:1 and a lock-up converter.
Q: Do you offer cooler fittings for AN connections?
A: Yes, you do have the option to purchase a fitting that will have #6 AN fitting (#831011).
Q: Is this a factory planetary?
A: No, this is a 6 pinion rear and 5 pinion front planetary that is designed and manufactured at TCI®.
Q: Can I use my factory LS1 (2,3,6,7, etc.) flexplate with this transmission and converter.
A: No, you will have to use one of our LS1 flexplates (#399754 LS1 wide GM wide pattern, #399755 LS9, or #399756 LSA), and the crank adapter that comes with each flex plate.
Q: How much horsepower will the transmission withstand?
A: The 6x has a limited lifetime warranty up to 850HP
Q: Can I use my factory steering wheel with the paddle shifter?
A: No. You must use an aftermarket 5 or 6 bolt style steering wheel.
Q: How many quarts of fluid does it hold?
A: Typically the 6x will hold 12-14 quarts but that will vary depending on converter size.
Q: Will it work with a PCS controller?
A: No
Q: Will my MAC laptop connect?
A: Yes, but you will need to call TCI® for details on how to set it up.
Q: What is HDT Coating™?
A: HDT Coating™ means “Heat Dissipating Technology™”. It is a specially formulated coating that we use on every transmission and torque converter to help dissipate heat that is generated in normal operation.
Q: Will the paint on the inside of the pan gum up the valve body and destroy my new transmission?
A: No. The coating on the inside of the pan is an “E-Coating” that will not come off or harm the transmission. Some OEM’s have used this same coating for numerous years.
TCI 6x Six-Speed Transmission FAQs 
Linear Mode
