TH350 vs 200-4R Differences

TH350 vs 2004R Transmission

The TH350 was GM’s go to transmission for light duty vehicles from the late sixties through the early eighties, that is until the 700R4 and 200-4R began to replace it.  When comparing the 200-4R (often called the 200r4) vs the TH350 there are quite a few differences, and also quite a bit in common.

The biggest difference between these transmission is going to be the overdrive gear.  The 200-4R has overdrive and the TH350 does not.  Both transmissions have an aluminum case with an integrated bellhousing, and are not controlled by computer.


Related:  TH350 vs. TH400TH350 vs 4L60E, TH350 vs 700R4


200-4R vs TH350:  Biggest differences

There are many differences between the TH350 and 200-4R transmissions.  We’ll get into them more below, but the largest ones have to do with how they are controlled, and one having an overdrive gear and the other one not having that gear.

  • Shift control–  The TH350 is controlled by engine vacuum and a kick down cable.  The 200-4R is controlled by a TV cable.  The best way to think of the TV cable is as a throttle position sensor.  It controls shifts based on how much throttle is being given at any time.  It is easy to swap transmission control to a TV cable if you are thinking about swapping to a 200-4R.  Here is more info on the TV cable.
  • Overdrive–  The 200-4R uses an overdrive gear to reduce engine RPM at highway speed.  The TH350 has three forward gears and no overdrive.  It’s worth noting that the overdrive gear on the 200-4R is even more aggressive than the 700R4.  .70(700R4) vs .67(200-4R), which means that the 200-4R will make the engine turn even slower on the highway.

There are many other differences between the two transmissions that are noteworthy as well.  This is a broad take on these differences.

  • Locking Torque Converter–  The 200-4R has a locking torque converter, which means that a clutch will engage at a high enough speed and allow for a true direct connection between the engine and transmission.  This increases fuel economy and slightly lowers RPM going down the road.  You have to set up wiring to make it work in a car that it was never equipped with.  A car with originally equipped with a TH350 is not going to have the wiring built-in.
  • Length–  The TH350 is a barely shorter than the 200-4R, but the mount is about 6 inches further back.  This may cause some problems with finding the right crossmember if you were to swap one for the other.
  • Gear Ratios–  The TH350’s gears are placed closer together (despite having less of them).  But, they are much closer tougher than the 200-4R vs 700R4.
TH350 vs 200-4R Gearing 1st 2nd 3rd 4th Reverse
200-4R 2.74 1.57 1.00 0.67 2.07
TH350 2.52 1.52 1.00 N/A 1.92

200-4R vs TH350:  Conclusion

There is one main question that you need to be asking yourself:

What is overdrive worth to you?

Almost every modern car has an overdrive transmission.  If you didn’t grow up in the time when a TH350 equipped car would be in your daily driver, you may not remember the engine screaming down the highway.  It is not as fun as it sounds.

It’s much nicer to listen to the engine hum down the highway in overdrive sipping, not guzzling, the gas.  Unless you really want to do hardcore racing, you should take a look at the 200-4R.  There’s not a whole lot involved in swapping one to the other, and it’ll make driving your car a joy!