The GM 4L80E transmission is a computer –

The GM 4L80E transmission is a computer-controlled unit that is the TH400’s successor. This transmission is basically the TH400 with the addition of an overdrive gear. Both transmission models are legendary due to their elevated level of reliability from the factory and, although their specs are similar, the 4L80E is several inches longer. This means you’ll need to purchase a new driveshaft to swap them out

4L80E Transmission Identification

4L80E transmission identification is fairly easy when using a process of elimination since there are only a few transmissions it can be. When comparing components side-by-side, the GM 4L80E is significantly larger than the TH350 and 4L60E. You can identify the 4L80E compared to the TH400 because it’s several inches longer.

If you’re viewing a transmission and don’t know where to start, look for computer control and a circular wiring harness connector. This immediately eliminates all classic GM automatic transmissions and narrows it down to the 4L60E, 4L65E, 4L80E, and 6L80E.

With every GM longitudinal transmission, another effortless way to identify the 4L80E is by the number of bolts found on the transmission pan. The TH400 and TH350 are the only two transmissions that share the same bolt count. Therefore, if you count 17 bolts, then you have identified the 4L80E transmission. Its successor, the 6L80E features 20 bolts, so there is no confusion between the two.

Technical Specs

Manufactured by General Motors and produced between 1991 and 2005, the 4L80E transmission specs are as follows:

• Type: four-speed automatics with a 6.2 quart capacity within the standard models.
• Gear ratios: first – 2.48, second – 1.48, third – 1.00, fourth – 0.75:1, reverse – 2.07:1.
• Input shaft: 32 splines.
• Torque converter lock: yes.
• Overdrive: yes.
• Case length: 32 inches, although different applications have different lengths because of varying transfer cases and tail shafts.
• Out case material: aluminum.
• Computer-controlled: yes.
• Weight: 187 pounds, not including the converter.

Common Problems 

Despite its durability and reliability, two problems exist with the 4L80E transmission, including:

• Erratic shifting: the 4L80E suffered a failed throttle position sensor or speed sensor, which caused shifting problems.
• Overheating: while transmission fluid helps eliminate the heat generated from moving internal components within the transmission, if a heavy load is towed or hauled and the 4L80E transmission cooler can’t cool properly, it could lead to overheating. This results in potential damage to the seals, valve body, clutches, etc.

Recommended Upgrades

When rebuilding the 4L80E transmission, several upgrades can be included to add power and performance. A stage 1 performance transmission super rebuild kit includes a performance overhaul kit, bushing kit, thrust washer kit, two bands, a transmission deep pan filter, steel clutch pack, and a stage-1 friction clutch pack. This type of rebuild kit allows the transmission to withstand high horsepower, improves torque capacity, maintains piston travel, and delivers higher heat resistance and smoother engagements for better overall performance.

A level 3 upgrade boasts automatic shifts with a heavy-duty performance lock-up torque converted, second stage shift kit, Kolene steels, clutches from Red Eagle, direct and intermediate clutches, and Power Packs from Red Eagle. The 16 elements intermediate sprag and carbon fiber band are replaced by the 34-element spray, which features a 1,000-horsepower rating. Pictured above is the Suncoast Alto Category 4 rebuild kit.

While the legendary 4L80E transmission has a few potential issues, it’s a powerhouse as a stock transmission. When adding upgrades, this transmission only gets better with more performance specs. Identification of the stock transmission is fairly easy, especially when counting the number of bolts in the transmission pan. All this information is brought to you by a top retailer of standard rebuilt 4L80E transmissions, https://reman-transmission.com/transmission-codes/?code=4L80-E.