LS1 Transmission

by

The LS1 engine first made its debut in the 1997 Chevrolet Corvette.  One year later, it made its way to the  Camaro Firebird twins.   All automatic transmissions that the LS1 came with are computer controlled.

The LS1 engines really used two different transmissions.  Those were:

 

  • T56– This transmission is the manual option on all of these cars.  It has six forward gears.  The fourth gear is a direct drive.  The fifth and sixth gears are both overdrive gears.  With this transmission the LS1 was quite capable of upper 20’s in mpg.  The T56 is nearly bulletproof and finding one with 100k should not be cause for concern.  The non Vette versions go for almost 2k on eBay.
  • 4L60E– The automatic version of the transmission that came with the LS1 is the 4L60E.   Some cars were equipped with the 4L65E.  For all intents and purposes.  This is the same transmission.  They look identical on the outside.  The 4L60E has four forward gears.  The third gear is the direct 1:1 drive.  Fourth gear is a .70:1 overdrive.  This transmission is quite reliable.  Shifts are controlled by the computer using telemetry from the engine.  That’s where the “e” comes from in 4L60E.

 

LS1 Transmission for the Corvette

LS1 Transmission

The Corvette transmissions are different than any of the other LS series transmissions.  That’s because the Vette went with transaxles for the C5 generation in order to get closer to the desired 50/50 weight ratio of a true sports car.  This means that the transmission is behind the driver, instead of in front of them.  It uses a torque tube to get the power to the transmission.

Since the engineers at General Motors used modified versions of the LS1 transmission for the Corvette.  They are not compatible with any other LS1 transmission.  You will often see these transmissions going for peanuts on EBay.  They are not compatible at all.  In fact, if you see a T56 going for less than $1,000, this should be a red flag.  They never have a traditional bellhousing noted to them.

 

  • T56– The Corvette used a custom spec T56 to fit in its transaxle.  The design only makes one suitable for transplant into another Corvette.
  • 4L60E– Just like the T56, it is only going to work for the Corvette.

 

The good news is that if you are looking to pick one of these transmissions up for the Corvette, they are considerably cheaper in used condition than the traditional transmission bolted straight to the engine version.

 

LS1 Camaro Transmission

Unlike the Corvette, which changed from the C4 generation when it got the LS1, the Camaro was in the middle of the 4’th generation.  While the Camaro and Firebird.

 

  • T56– This version of the T56 is the most desirable for people swapping one into an older car.  This is due to the excellent shifter location.  It’s right on top of the transmission.  The other ones use linkages to reach the shifter.  A low mileage version of this transmission is going to be the most expensive of all T56s in the used arena.  It is extra important to make sure that when you are looking at a potential T56 replacement for an LS1 Camaro or Firebird, that you don’t inadvertently end up purchasing one of the T56 transmissions that came with the LT1 engine.  They use a pull instead of push throw-out bearing.  They also need a different input shaft.  The geometry is all off.  With the right bellhousing and input shaft they will technically work though.  Here’s a good writeup of differences between LT1 and LS1 T56’s.
  • 4L60E– Same story as the T56.  The transmissions will not bolt to one another’s engines.  Unlike the T56, the 4L60E was also put behind the six-cylinder version of these cars.  These 4L60E’s will not bolt to the LS1.  Make sure that you know how to identify which is which.

 

 

GTO LS1 Transmission

The only other major muscle car that came with the LS1 was the Pontiac GTO.  These cars are based off of an Australian design, and had a very limited run in the United States.  There really isn’t much about them that you need to look out for.  They never had the old small block Chevy, so compatibility isn’t really an issue.   They also use the standard engine and transmission layout, so there’s nothing there either.

 

The only thing to really keep in mind is that if you are looking for a replacement T56, the shifter is in a different place, so they won’t easily swap out with the LS1 Camaro.

 

Other transmissions with the LS1

It is quite possible to use many other transmissions with the LS1.  There is a whole article on it here called LS swap transmission guide, so head on over there if you really need to research.  Here are some of the broad strokes though.

 

  • You can bolt almost any transmission up to the LS1, even the classic GM transmissions. All the way from the  Powerglide to the TH400.  This is thanks to GMs retaining of the same basic bolt pattern for the bellhousing.  There will be an unused bolt hole in some applications, but this does not compromise structural integrity.
  • The older gm automatic transmissions also need a spacer to get the flexplate and torque converter to hit at the right location.
  • Any transmission swap is going to require a re-flashing of the computer. The transmission shift codes will have to be removed so that the LS1 engine runs without considering the transmission.

 

Feel free to leave a comment if there is anything you’d like to add!