Transmission Swap




Disclaimer:  If you are doing this yourself make sure you have a transmission jack, that it is safe to get under the car and that you know what you are doing.  Transmission are almost a couple hundred pounds.  Don’t go getting yourself seriously injured or killed.  This is a project that requires a high level of mechanical knowledge.

Direct Replacement Swap

The good news with this one is that the toughest thing you’ll have to do if you are having a reputable shop do it is determine whether or not to rebuild the transmission, go with a remanufactured unit, or have the transmission shop itself rebuild it.  This is no easy decision.  The number one thing to consider is the mileage of the vehicle and how long you plan on keeping it.   In most vehicles the automatic transmissions will fail before the motor itself.  This is usually due to:

  • Age and wear-  Father time is not kind to moving parts,and transmissions have thousands of moving parts.  They are eventually going to fail
  • Low or no fluid-  Although people are generally good at changing and monitoring the oil in their vehicles.  The transmission fluid is often neglected.  There are some cars out there now where the transmission fluid can go the whole life of the vehicle.   Just check when the manufacturer suggests that you change it.
  • Driving habits-  Brake torque burnouts, shifting the trans yourself consistently, and a heavy foot are all things that cause the trans to go quicker.  What you do can often affect what kind of mileage you get from the transmission.  On the highway it just has to stay in one gear.  Off the highway, it is constantly shifting.
  • Heat-  Overheat the transmission and it’ll really hurt.  If you suspect this has happened to you a fluid service may be in order.

 Automatic to Manual Swap

The second type is automatic to manual.  This swap is something that you need to look beyond just the price of the transmission.  There are a few situations you’ll encounter.

The car was available with this transmission as a option from the factory.

If this is the case you’ll just need to gather factory parts for the swap. Getting a clutch, crossmember, pedal, flywheel, and whatever linkage happened to come with the car.  You’ll probably also need to get a new driveshaft or have the one you currently own shortened.  This will be significantly more straight forward than if the car never came with the transmission at all.

The transmission you are swapping in was never available in your vehicle ever.

If this is the case for you hours of research will save you from months of having your car down trying to figure out just what happened.  Do not procede until you can answer these basic questions.

  • Do my clutch, flywheel, and throwout bearing work TOGETHER?  It is vital to make sure that these things were designed to work together.  Although you may not have a vehicle that ever came with the transmission that you are looking to pair with, it’s still very likely that the engine and transmission have been paired together before.  The exception to this would be something like the super popular Tremec TKO series.  The good news about going with something such as this is that the aftermarket fully supports this for almost any kind of swap.  The bad news is these solutions are not going to be very affordable.
  • Does the transmission fit the driveshaft tunnel?  I have a Nova, and I know for a fact that I can not put a T56 6 speed transmission in there without hacking the heck out of the tunnel.  It’s not a big deal, but if you prefer keeping the stock floor it’s something worth looking into.  The good news is that the internet is awesome.  You’ll be able to find somebody who was nice enough to take pictures of the swap and lay it out for you in most cases.  If you can’t tread lightly.  You’ll probably be looking at least a little fabrication.
  • What clutch linkage can I use?  You’ll have to be careful here.  A mechanical linkage is usually less expensive, but it’s not nearly as flexible as a hydraulic one.  The odds are that you’ll need to get it around exhaust or a steering shaft that it was never meant to get around.
  • What about the pinion angle? You’ll need to make sure that the geometry is correct from the tail shaft to the rear end.  There are tools and shims out there to verify this.  If you are using all factory parts, it’s probably not necessary, but still not a bad idea to check.  If you get everything done and hop on the highway and you get a vibration you’d better verify that you don’t have an issue with this.

Manual to Automatic Swap

I live in the United States, and I am assuming that you do to.  Here in the States it’s almost impossible to find a vehicle that doesn’t come with an automatic transmission.  So if you are looking to make the swap (drag racing?) than it’ll be pretty easy.

  • What do I do about the shifter?  There are really 2 options here.  You can go out and get a steering column from an automatic version of your vehicle at a swap meet, salvage yard, or find one online.  Than it’s as simple as swapping out the columns.  Ok, it’s an arduous task, especially if you don’t have an ignition key for the new column.  You’ll also need to get a factory shift linkage and hook it up.  Or you can get a floor shifter from a company like B&M, or Hurst.  They come with a flexible shift linkage.  You’ll just need drill a hole to get the linkage through.  You’ll also need to set up the neutral safety switch (seriously do this).  It’ll also have reverse light hookups.  It’s a heck of a lot quicker than adapting a factory column.
  • Can i reuse the factory driveshaft?  In general manual transmissions are longer so you’ll probably just have to have it shortened.
  • What about cooling?  You radiator should have hookups for the transmission fluid cooling lines.  If your car runs hot normally consider a dedicated transmission cooling unit.

 

Posted in tech, transmission swap

Leave a Reply

Your email address will not be published. Required fields are marked *

*