Re: Neat Jaguar specific 4L80E site
army helo pilot said:
I am pretty new to this stuff but is the 4L80E a torque converter? What does is do (apart from the obvious - converting torque?)
What is the difference between 400s and 700s that people talk about? Thanks,
Mark
Thats a pretty broad question(s) but the basics are that the numbers you see (4l80e, 700r4, th400, etc) are just GMs designation for the different types of transmissions available. As in the 700R4 and the 4L80E are BOTH 4 spd automatic overdrive transmissions for rear wheel drive applications and they perform the exact same
function but are completely different in their torque/hp ratings and the manner in which they work internally. Same deal as the difference between a honda accord and a Impala SS....they both serve the same purpose and do the same thing (get from point A to point B) but if you took each car apart and compared the pieces they are completely different machines on the inside.
The 400 and/or 350 numbers you see thrown around on here are the same scenario as in the piece in question is an automatic transmission as and the numbers are just what GM uses to designate the different models of an automatic transmission that has three forward gears (no overdrive) for a rear wheel drive application. Officially they are call Turbo hydromatic 350 or Turbo Hydromatic 400 (TH350 or TH400 for short) and the same differences as the 700 and 80e apply here. The th350 is rated for less hp/tq from the factory as the th400 just like the 700R4 is rated for less hp/tq (a LOT less) than the 4L80E. Basically its just a way to communicate what particular type of transmission your talking about without having to say the entire name. Which would you rather have to say or type multiple times in the same conversation "turbo hydromatic 400" or just "400"? Id pick "400" myself.
To further confuse you the 700R4 was renamed the 4L60 in the early/mid 90s but both are basically the same trans. Later on it the letter "E" was added to the end of the number to specify the trans was
Electronically controlled using a PCM (power train control module).
To sum it up for ppl who dont like to wade through my lengthy ramblings:
TH700R4= GM designation for the turbo hydromatic light/medium duty RWD 4 spd overdrive transmission.
4L60=GM just changed the name from 700R4 (there is more but generally speaking and for this conversation thats about it)
4L60E=GM designation for an electronically controlled 4L60/700R4.
4L80E=GM designation for a heavy duty RWD 4 spd automatic overdrive transmission that is electronically controlled.
TH400=GM designation for the turbo hydromatic heavy duty RWD 3 spd automatic transmission.
TH350=GM designation for the turbo hydromatic light/medium duty RWD 3 spd automatic transmission.
Lastly there isnt a universal designation for some of the above transmissions among gear heads. As in you'll hear ppl call a turbo hydromatic 400 transmission a "400" or "turbo 400" or "TH (pronounced tee-aitch) 400".....the same deal with the TH350. The TH700R4 is commonly called a "700" as well as the 4L80E being just called an "80E" for short.
All of these transmissions multiply torque using the internal gear ratios as well as a torque converter which is directly driven by crank shaft of the engine.
Class dismissed and there will be a pop quiz at the end of the week
![Quickstop [UK]](/data/avatars/m/5/5165.jpg?1570199786){kind=avatar}