First, a little background on the 4L60E.

The name 4L60E stands for 4 forward gears, a longitudinal mount (for rear-wheel drive) a 60 relative torque rate at 360 lb-ft, and an electronic valve body. 

Here are a few specs for the 4L60E:

Here are the 4L60E’s gear ratios:

Let’s say you’re wanting to do a 4L60E swap on an A-body vehicle (one of the more common swaps). For this situation, you’re probably going to need to budget somewhere between $3,800 and $4,500 for the swap. But it will be worth it! If you need a transmission to start with, here’s a good cheap rebuilt 4L60E for sale, https://reman-transmission.com/transmission-codes/?code=4L60-E.

The 4L60E is an electronically-controlled overdrive, meaning in a swap it’s going to need electronic “gatekeepers” such as a standalone controller, throttle position sensor input, and the ability to convert the electronic signal to a usable speed display. 

You’ll also need a few mechanical considerations such as a somewhat shortened driveshaft and a few floorplan modifications, most likely.

Once you have these considerations in place, you’re ready to install the trans. The bell housing bolt pattern will likely be the same for the A-body (the 4L60E trans is a 90’s design and generally pays homage to older auto bodies). In this situation, you might use a lockup torque converter with a new flexplate to facilitate an externally balanced 383 small-block setup.

Next, you’ll remove the old trans (let’s say you’re working with a TH350) and bolt 4L60E into place for the moment. Make sure you have clearance for the servo cover and the right-angle AN cooler fits. You might need sheet metal cuts. The 4L60E is going to need a little room. 

To get to the converter bolts for the 4L60E you’ll need to access through the starter motor hole, so remove the starter and torque the converter bolts to the TCI flex plate. If you need to use a replacement starter to accommodate the smaller space, that’s no problem. 

Once you bolt in the transmission and new starter motor, you should now permanently mount the trans and get your measurements for your new driveshaft. The 4L60E is generally going to be a little bit longer than other models like the TH350, so you’ll need to shorten the old shaft or just build a new one (or have someone build it for you).

When measuring, put the rear axle at the height of the ride. You can also use a drive-on hoist or 4 drive-on ramps of exact height. Don’t cut corners on the measurements. Guessing now could lead to a rough situation down the road.

Next, route your custom AN cooler lines to your engine radiator. Then mount your TCI controller in the passenger fender and route any necessary wires to the interior. 

Bolt your electric motor in place and connect your wiring to tap into the input from the VSS. You might need to do some road testing to calibrate. 

Next, connect your column shifter to the new trans. Research a few manufacturers who offer rods with adjustable quadrants that can work well with the 4L60E. 

Now, once you’ve put your driveshaft into place, it’s time to test your trans. Try it at different RPMs. And make sure to get your 4L60E tuned up before trying anything heavy. It might be best to go with an electric overdrive automatic.

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