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Modern Driveline is a TREMEC Elite Distributor
Full Service authorized TREMEC Elite Dealer including repair center and Warranty repair.  

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The TKO series is the most popular choice for 5-speed conversions in new and classic cars. For specs and more information see our TKO page.

  • How many shift positions does a TKO have?

    The older 3550/TKO's have three positions. TKO-500/TKO-600 transmissions have three positions. (NOTE: originally there were four. The fourth being the very front position. This position has proven to be problematic and has been obsoleted. The access plate is still there but can not be used as a shifter position.) The TKO-500/600 transmissions have three basic positions. 1. Rear (default) 2. Rear/Forward (Rear shifter flipped) 3. Mid-position (Whole new shifter mechanism) In addition to these basic positions, we also carry a line of short throw shifters which can be configured with offset left, right, forward, backward to fine tune the position of the shifter stick.


  • Are the mounting points and overall size of TKO-500 and TKO-600 different from the 3550 and TKO?

    No they are the same. The new TK0-500/600 have a new shift location for vintage GM and an additional electronic speedometer hookup on the passenger side of the tailshaft housing.


  • What is a TREMEC 3550-II or TKO-II series transmission?

    Series II TREMEC's are .83 over drive geared transmissions best suited for road racing when a tall over drive is not needed. These transmissions have been replaced by the TKO-600RR.


  • Which type of oil is used in a TREMEC 3550/TKO and TKO-500/600?

    GM Syncromesh only. The syncro material in these transmissions benefit from and shift better with Synchromesh rather than the ATF used in the T-5 and T-56.


  • Is there a TREMEC TKO that will replace a Muncie without adapter plates or bellhousing swap?

    Yes, a GM TKO. It come's in both TKO-500 and TKO-600 gearsets. The TKO-500 has a 3.27 first while the TKO-600 has a 2.87 first gear ratio. There are two overdrive ratio's available, .68 and .82. It has the GM Muncie bolt pattern and GM input shaft. The speedometer cable drive requires an adapter we offer.

    Call us for details.


  • Is there a TREMEC TKO that will replace a Ford 3 speed or 4 speed toploader?

    Yes, a shortened input shaft TREMEC 3550 or TKO-500. If you are willing to change the clutch to a 26 spline, a TKO or TKO-600 with a shortened input shaft can be used. A second option is to use a spacer plate (MD-401-2108) to make up the difference in length of the TKO's standard input shaft.


  • I was considering swapping a big block in place of a small block in a 1968 Mustang. The car has a C-4 now. Do you have a gearbox that will take the torque and a conversion kit?

    Yes - What you will need is a TREMEC TKO, TKO-500, or TKO-600 with a shortened input shaft to bolt directly to a stock Ford BB bell housing or aftermarket scattershield.


  • Do we offer a aftermarket mid shift kit for TREMEC 3550/TKOs and the new Tremec TKO-500/TKO-600?

    Yes we do. We have kits for both the older 3550/TKO's and the new TKO-500/600's . The kits come with a rear position cover and is a much better choice over the TREMEC stock offering for the same money.


  • Can I install a TREMEC TKO into a 65-66 Mustang without cutting the floor to get the proper drive angle?

    No, the TREMEC 3550 and TKO are much too tall in the main case and needs more room to achieve the correct drive angle. If the transmission is allowed to hang down, the case is exposed to road clearance hazards and will cause vibration, especially when decelerating. To properly install a TREMEC 3550 or TKO into a 65-66 mustang, the floor trans tunnel should be raised about 1.5.


  • Can a shifter be installed where the other two inspection covers are now?

    Yes/no, only the Mid-position is available. Note, the factory front shift is obsolete. Contact us with your application and we'll recommend the correct combination of position and shifter offset to accommodate your needs.