he 4L80E is essentially a TH400 with an overdrive gear added.
They are both legendary for their bulletproof reliability straight from the factory.
Their specs are similar, although the 4L80E is a few inches longer,
and a couple inches wider at a few points, making a trans swap or the trans fit ,
in some cars trans tunnels a bit more difficult
which means you’ll need to get a new driveshaft if you were to swap one for the other
They both have the same forward gear ratios, only the 4L80E gets the overdrive gear of course.
That overdrive gear is not as aggressive as the overdrive on the 4L60E
It is a very heavy transmission. In fact, it’s 27 pounds heavier than the 4L60E.
Is the 168-tooth flexplate stock for 1985? I seem to get different finds on my own search. It needs to be externally balanced for my 383 [for 1985 Corvette auto trans - new short block w/ 400 crank] Appreciate the help
4L80E Transmission Specs
Manufacturer: General Motors
Type: 4 Speed Automatic, 6.2 quart capacity (standard models)
- First- 2.48
- Second- 1.48
- Third- 1.00
- Reverse- 2.07:1
Input Shaft: 32 spline
Torque Converter Lock: Yes
Case Length: 32″Different applications had different lengths due to different tail shafts/transfer cases. Use this diagram
to help you.
Outer Case Material: Aluminum
Controlled by Computer: Yes
Weight: 187 pounds without the converter
this is the golden era for horsepower. But that added power puts even more pressure on the rest of the driveline, and no more so than on the transmission. The good news for GM fans is that when it comes to automatic transmissions, there are multiple options. The trans we think has been overlooked is the 4L80E Transmission. This cryptic description is GM's way of saying this is an automatic transmission with four forward speeds designed for longitudinal (i.e. RWD) use. The "80" references higher torque capacity (compared with a 60, for example), while the "E" defines this as an electronically controlled transmission. We did some research on some of the more important aspects of performance uses for this transmission.
You can think of this trans as basically a TH400 with a 25 percent overdrive tacked on. The 4L80E transmission was mostly used in 34- and 1-ton trucks and larger SUV applications beginning in 1991. The "E" means that it must use an electronic ECU for control, as it will not function without it. The trans has experienced multiple minor upgrades over the years, with the newer boxes being a bit more attractive, but all the versions can be made to work well in a performance application. The addition of electronic control and overdrive adds roughly 50 pounds and a slight amount of width over a TH400, but for the most part, any floorpan that can accommodate a TH400 can also fit a 4L80E. Also, the 4L80E transmission is typically about 4 inches longer than a TH400 (depending on the length of the extension housing), but the trans mount is located roughly 112 inches rearward.
Most of the concerns about rL80E transmission revolve around the need for electronic control. Car Craft did an extensive review of five aftermarket controllers in the Mar. '12 issue, evaluating units from Powertrain Control Systems (PCS), TCI, Chevrolet Performance (GM), CompuShift, and Painless.
Be aware that if your car is carburetor-equipped, an aftermarket conversion will also require a throttle-position sensor (TPS) adapter to the carburetor throttle linkage. Holley and most of the companies that sell the controllers also offer a TPS adapter. The price (between $600 and $1,000) and function of these controllers vary, so a review of our story is advised to help you decide which one would be best.
So while the 4L80E is affordable, there is some expense involved with converting it into an earlier chassis. If you've been adding up the costs in your head during this story, it wouldn't be surprising if the cost exceeded $2,000, even if you find a used 4L80E for around $500. But isn't half the battle knowing how deep the water is before you dive in headfirst? The advantage here is a trans that is even stronger than the original TH400 and offers an excellent 25 percent overdrive.
4L80E Transmission Specs
Dimensions (inches) A B C
TH400 28-3/4 27-1/4 2-1/2
4L80E 32 30-1/2 4-3/8
Description PN Source Price
70434 Summit Racing $849.95
TCI Saturday Night Special 242900 Summit Racing 530.95