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The 4L85E transmission is a series of an automatic transmission from General Motors. It is also popular since it is a heavy-duty transmission that was improved upon to make it handle more torque and impact driving.

What’s more, it may be over a decade since it was launched, but its solid build makes it a contender with older transmissions. Thus, it should not come as a surprise that car enthusiasts are continually looking for ways to upgrade their transmission to be even better.

Here’s an overview of the 4L85E transmission that informs you of its specification, differences from other series, problems, and improvements.



The 4L85E is a 4-speed automatic transmission that was launched by General Motors in 2002. Like the 4L80E transmission, it was an upgrade to the TH400 three-speed transmission from GM.

Hence, it can be considered as a TH400 with overdrive, a lockup torque converter, as well as advanced electronic controls. However, the 4L85E can handle more torque (460 lb-ft of torque) than the 4L80E transmission.

It has been rated to handle vehicles with a GVWR of up to 18,000 lbs and 690 ft·lbf (935 N·m) of torque. As a result of its exceptional strength, this transmission is suitable for drag racing, off-road racing, and even custom street driving.

Some cars that used the 4L85E transmission include heavy-duty GM trucks and vans, and also a classic Chevy with a big-block. Specifically, these cars were:

    • Rally Fighter
    • GMC Yukon XL
    • Chevy Suburban
    • Chevrolet Avalanche
    • GMC Savana with Duramax Diesel
    • Chevrolet Express with Duramax Diesel

For this reason, the 4L85E can be used for large vehicles that are meant for off-roading or heavy-duty transporting.


4L80E vs. 4L85E

There are several differences between the 4L80E and 4L85E transmission, even though these were upgrades to the TH400. The popularity and strength of the TH400 may have rubbed off on the 4L85E, but it still brought something unique to the table.

Some of these differences include:

    • The 4L85E transmission is rated up to 460 lb-ft, but the 4L80E is rated up to 440 lb-ft.
    • The 4L85E transmission featured a five-pinion reaction gearset and a five-pinion output gearset.

Some parts that were improved in the 4L85E were:

    • Input and reaction carriers.
    • Improved overdrive planet and drum.


4L85E vs. TH400

Like the 4L80E, there are also differences between the 4L85E and the TH400 transmission. Notable among these is its physical appearance.

Here’s what it looks like:

    • The 4L85E is 26.25 inches longer than the TH400.
    • The 4L85E is also bigger than the TH400, which is evident in the length and size of the pan.
    • Despite its large size, the 4L85E is also easy to fit into a car, and even easier than the 4L60E series of transmissions.



Despite the huge improvements in the 4L85E transmission, there are still specific problems that have been reported by users of this transmission. Notable among this is the case of slipping or not syncing on time when the transmission is placed in drive.

The problem is also evident when trying to move from 1st to 2nd gear or 2nd to 3rd gear, since more time may be taken to respond – It’s the case when it takes twice the time to shift to gear. On the other hand, slipping can lead to overheating, which can cause the transmission to burn.

The damage can be so severe that it would be difficult to rebuild the transmission. Alternatively, the 4L85E can notify you of a slip when there is an increase in the variable pump pressure. As the transmission wears, this pump pressure is increased, and as such, slipping may not occur until the transmission fails.

Over and above that, there’s a reported case of the wire harness for the trans cracking, and thereby allowing transmission fluid to enter the connector end. The latter results in a short, which is noticeable when doing hills/grades.



The 4L85E transmission may offer considerable strength, but some improvements can be made to it in order to increase its performance: For starters, the transmission cooler using its own electric fan can be installed in the transmission in a bid to promote good airflow.

Similarly, a shift improver kit can be used to improve the 4L85E transmission. What this kit does is to:

    • Give the driver more control of their vehicle.
    • Decrease the transmission of internal line pressure.
    • Decrease the time required for the clutch and bands to engage. And in return, heat and wear are reduced during off-roading.

These aside, GM has made an improvement to the 4L85E and now, there is the SuperMatic 4L85E transmission as is evident in the Chevrolet cars.



The SuperMatic 4L85E transmission is an improved version of the 4L85E and as such, it is also a heavy-duty transmission. This variant, however, has unique differences that set it aside from the 4L85E.

For instance, it features an additional heavy-duty clutch plate and has revised valve body calibration as well as increased fluid pressure. The gear ratios of this transmission are 2.48, 1.48, 1.00, and .075 for the 1st, 2nd, 3rd, and 4th gears respectively.

In comparison to the 4L85E, its gear ratios are 2.48, 1.48, 1.00, 0.75, and 2.07, from First through Reverse. On the other hand, the SuperMatic 4L85E transmission is suitable for Gen I small blocks and all big blocks.



An overview of the 4L85E transmission shows that it is also one of the most reliable GM overdrive transmissions. It can handle more torque than what is rated on paper, which makes it suitable for off-roading, and generally, vehicles that will need to handle a lot of impacts.

What’s more, it boasts of the same power as the TH400 and 4L85E and takes it one step further to be a good variant among the trio. The features of the 4L85E transmission can best be appreciated by comparing it with a range of series transmission that was launched before it.

We’ve covered this and many more in our overview; hence you can make the decision on which to settle for among a range of options.

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