Frequently Asked Questions

Here are some of the more popular questions (and answers) that we get.  If you can add to any of the following, we’d sure appreciate it!  Email us at:

Q:  Why is the TREMEC 5sp so special?
  Benefits include:

  • It’s a true Overdrive transmission
  • Increased gas mileage
  • 32% overdrive 5th gear drops 3000 RPM to 2000 RPM on the road
  • .83 optional 5th gear drops 3000 RPM to 2500 RPM on the road, typically used for road racing applications
  • Handles 425 or 525 ft/lbs 
  • Reduces noise, heat and wear
  • Great for both street and race applications
  • Very durable, some of the NMCA racers are running 9.30s in the qtr mile with the TKO
  • Versatile:  With the 8 shifter locations we can offer, and the various conversions we offer, the TR-3550 can be installed in most any RWD application (street rods, trucks, drag cars, hot rods,
    road racers, musclecars (all makes), Jaguars; you name it).

Q:   Is the GM version of the TR-3550 a direct bolt on?
  Yes, the GM version of the TREMEC 3550  and TKO is a direct bolt in, in that it bolts to your GM bellhousing, has a GM input shaft, uses the GM TH400/TH350 trans mount, and uses alll GM clutch, linkages, fork, bearing, speedometer cable, etc.  Now the exceptions:                             

  • Has a C4 or C6 output shaft, so you’ll need to install it onto your driveshaft
  • Your driveshaft will need to be shortened (most applications)
  • Depending on the make and model of your car, you may have to “lift” the tunnel to get the trans to fit. 

If you don’t have an existing opening in the floor for a shifter, clearly you’ll need to create one.

Q: What is a TKO or TKO II ?
  The TR-3550 TKO and TKO II are stronger versions of the TR-3550.

Q:  How would I install a TREMEC into my car?
  If your car or truck already has a TREMEC, then you shouldn’t have any issues or challenges.  If you’re putting a TREMEC into a GM application, your results will vary a bit.  Click the links below to see more details for your specific application.  If you don’t see       your specific application, call or send us an email and we’ll track down any information we can.

There are lots of installation detail pages on this site.  See the links at the bottom of the folllowing 2 pages:

Q: How does the TREMEC TR-3550 5 speed compare to a Richmond 5 speed?
  Following are some comparisons:

The TREMEC is a true overdrive transmission, where the Richmond 5 has a 1.00 5th.  Conversely, the TREMEC offers a 0.62 or 0.83 ratio 5th gear ratio.   Both transmissions offer basically the same 1st gear ratio.  

Q:  I want to order a GM TREMEC, what else do I need to get?
  We recommend a backup light switch, a GM speedometer gear adapter and gear.  The slip yoke comes with the transmission.   Of course we also recommend that you use a blowproof bellhousing.  You may also need to get your driveshaft length altered.  

Q:  What shifter bar would I use?
  The shifter bar mounts are basically the same as for your GM-style shifter.  So, any flat Hurst shifter bar should work just fine.  The only difference is that you’ll need two 8MM bolts to bolt the shifter bar on.   


Q:  What are the 3 connections on the driver’s side of the TREMEC TR-3550/TKO 5sp?
  They are the revese light switch, a speedometer attachment, and a servo switch.  The servo switch is used for factory computer applications, and serves as a neutral indicator.

Q:  What RPM will my engine turn with a 5 speed overdrive?
  See the information on the 5 speed comparison page.  

Q: What is the proper break-in procedure for a TREMEC TR-3550/TKO 5sp?

  1. Put 3qt of good quality ATF (Auto Transmission Fluid) (Dexron) into the transmission. Pour in through shifter mount,  or through one of the top plates.  You can use the fill plug on the side of the  transmission also (afterall, that's what it's for!).  It's just easier to pour it in from the top if you can.
  2. Put car on jacks, run the transmission up and down through all gears repeatedly for 15 minutes.  This will allow the gears to break in properly  (yes, with the engine running)
  3. After 500-700 miles, drain the ATF, and put in 3qt of the GM Synchromesh fluid,  the part number is 12345349. If it's a race car only, then switch to the GM Synchromesh after the initial break-in.
  4. Don't use synthetic lube for 6000-8000 miles.  In fact, we don't recommend synthetic, just stick with the GM Synchromesh.

Q: How do I install the 3550 using the 1st F-body crossmember?  The trans won’t fit over the crossmember...
  You need to cut off the torque arm bosses that are on the underside of the tailshaft behind the transmission mount.  See pics of this here.  You can use a 4” hand grinder with a cutting disk..

Q:  What transmission fluid do I use?
  The TR-3550 5sp uses the GM Synchromesh.  The T56 and 3650 use Dexron III ATF, and the Viper T56 should use Castrol Syntorque.  See the service manual for more details about your transmission.     


Q: Do I need to check the alignment of my bellhousing?
  Yes, this is a recommended procedure, especially if you have a Lakewood bellhousings.  The Lakewoods are known for being             mis-aligned.  I’ve heard the McCleod bellhousings are better aligned from the factory.  

Q: How does a 3550/TKO compare in size to a Muncie?
The 3550/TKO 5sp is about 2” longer, and is considering larger in size. 

Q: TREMEC or Tremec, which is right?
TREMEC is correct, it’s an acronym.  Not that it really matters, but we do get asked on occasion.  It is strange that so many people spell it as ‘Tremec’