Ol’ Cotton: The NV3500 Goes To The Scrap Pile

Nick Adams August 7, 2026 9 min read 0

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The transmission has been picked and acquired; we carefully stocked up on the parts and tools we need for the job, and now it’s time to get our hands dirty getting the old, clunky NV3500 5-speed out from underneath Ol’ Cotton and into the scrap pile so it can never let anyone down ever again.

Lifting Safely

Ideally, you want to do a job like this with a two-post lift and a hydraulic transmission lift to help. But, like a majority of our readers, we don’t have access to the big, fancy, professional equipment.

You will need to jack your project off the ground to have at least a foot or so of clearance from the underside of the frame to the ground. This isn’t just to give you enough room to wiggle around under the truck; it’s the minimum clearance you need to get the old transmission out and the new one in. Remember, the NV3500 is a big transmission like the Tremec Magnum.

You can use a set of tall, heavy-duty jack stands, but we prefer for a job like this to use cribbing or, in our case, Ol’ Cotton’s original wheels and tires that we keep in the shop as spares. This method is very similar to how many junkyards and pick-n-pull yards prop up their cars because it is simple and safe. Also, when it comes time to measure for our new driveshaft, this allows us to have the truck lifted while still sitting on its own weight.

Drain And Disconnect

Ol’ Cotton’s NV3500 was tired after 130,000-plus hard miles and was starting to leak a little from every available orifice, but most of the fluid was still inside, and we need to drain it.

The drain and fill plugs on the NV3500 use a 17mm internal hex key. If you don’t have one of these tools available, you can make one out of a bolt with a 17mm head and a couple of jam nuts, or, in our case, a bolt with a 17mm head welded to an old broken 3/8 socket.

While the fluid drains, it is a good time to disconnect the electrics. There are only two connections on the NV3500: the reverse light switch and VSS sensor. There are also some clips that keep these connectors and harness tucked against the transmission and away from hot exhaust, and you will need to detach these as well to keep from accidentally ripping your harness to shreds when you pull the transmission.

The drain plug on the NV3500 is a 17mm internal hex, which can be hard to find in your typical toolbox. Grab one at your local hardware store

Shifter And Hydraulics

It sure would be easy to leave the shifter in place when pulling the transmission, but the NV3500 has to move back over 4 inches so the input shaft can clear the pressure plate before it can be lowered and removed, and the hole in your transmission tunnel won’t let you do that.

The shift lever is threaded on the shifter base, and a little muscle will help you remove it. It has a small jam nut from the factory that may or may not need to be removed first, depending on how much whole milk your Mom made you drink as a child. The shift boot is bolted to the floor by a series of Phillips-head screws, and the shifter base is held in place with just four bolts that are removed with an 8mm socket.

The clutch hydraulics need to be disconnected as well, which can be done with a special tool on the single clutch line near the clutch master cylinder under the hood. But since we’re going to refresh all of the hydraulics for this swap, we decided to remove all of the original NV3500 hydraulics.

Under the dash, behind the clutch pedal, we removed the connector for the clutch switch and the rod at the pedal. Both of these can be done by hand with no tools, and the master cylinder is removed as an entire unit from under the hood by turning the master clockwise a quarter turn.

Already Exhausted

Now that we’re done under the hood and with the interior side of this job, for now, it’s time to climb back under Ol’ cotton to remove the driveshaft.

The rear U-joint of the driveshaft is attached to the yoke of the differential with two metal U-joint straps and four bolts. An 11mm box-end wrench and some muscle will be what you need to get these bolts loose and out of the way. A small pry bar, crow bar, or a large flat-head screwdriver will help you pry the axle from the driveshaft by sliding the driveshaft forward about an inch. But don’t pull the driveshaft just yet!

The straps on the rear U-joint are held in place by four bolts that are removed with a 11mm socket.

Before you yank the front yoke out of the tailshaft of the NV3500, it’s time to put the fluid drain plug back in and move the fluid drain pan under the tailshaft of the transmission. All the fluid has been drained from the maincase, but more will fall out when you pull the driveshaft and make a big mess without a drain pan to catch it.

Once the driveshaft is pulled and set aside, you can use the output shaft plug off the Tremec Magnum on the NV3500 to keep the mess to a minimum during removal.

Clear The Way

We’re getting closer, and there isn’t much left holding the old NV3500 in place. Just some bellhousing bolts and transmission mount. Before either can be removed, you have to safely support the transmission.

A proper transmission jack is worth every penny. Even though we remove the old NV3500 with a typical floor jack, it would be safer and easier with a tranny jack. And, you will need one to install the Tremec Magnum.

You can do this with a normal floor jack, if you are very careful like we did, but it is highly recommended to use a purpose-built transmission jack you can buy or rent from your local hardware store. This is all but required to install the Tremec Magnum, which we found out the hard way in next week’s video, but it is easier and safer to remove the NV3500 with this tool as well.

With the NV3500 held in place with your jack, you can remove the single 13mm nut holding the transmission mount to the crossmember and use an 18mm wrench and 18mm socket to remove the four large crossmember bolts and nuts. Now the crossmember simply drops out of the way and can be set aside for later.

Time To Lower It Out

All that’s left now is just 8 bellhousing bolts holding the NV3500 transmission to Ol’ Cotton’s 5.7-liter LS engine. A 15mm socket will get them all out, but you will need a few long extensions to reach the ones at the top of the bellhousing.

It will help to use your transmission jack to lower the NV3500 at a slight angle to get to those hard-to-reach top bolts, and contrary to what you might be thinking, it’s best to get these out of the way first.

Only eight bolts need to be removed with a 15mm socket, and some extensions for the top bolts, to get the NV3500 out.

Once all bolts are out, some wiggling and pulling the NV3500 rearward will get the tip on the input shaft clear of the clutch pressure plate so you can finally lower it all the way down and slide it out from underneath the truck.

Old Clutch Kit Out

Before you scramble to get the new Tremec Magnum on the transmission jack and slide it under the truck in excitement, which even we admit is very tempting, you have to get the old clutch and flywheel out, too.

The NV3500 is tall, even when sitting on the ground, but we lifted Ol’ Cotton just enough to wiggle it out.

The stock pressure plate is held in place by bolts that use a 13mm socket to remove. Be careful when removing the pressure plate and the clutch disc that will fall out with it; there will be a lot of old used clutch material and dust that will inevitably unsettle and easily get into your eyes or lungs, which is a one-way ticket to the doctor or emergency room.

Like the old NV3500 clutch and pressure plate, the old flywheel can’t be reused with our Tremec Magnum transmission swap either. The six flywheel bolts that will need to be replaced as well are removed with a 15mm socket. While the pressure plate bolts were tight but could be undone with hand tools, the flywheel bolts could use some help from an impact. If you don’t have a big air-powered or electric-powered impact, hand tools and a flywheel holder to keep the engine from turning can be used.

One More NV3500 Headed For Extinction

The old, tired, leaky, noisy, and clunky NV3500 5-speed transmission (can you tell that we’re happy to see it go?), along with the old clutch, flywheel, and driveshaft, are headed to the scrap pile.

While we’re sure we could throw these on Marketplace for cheap to recoup some money for our budget for Ol’ Cotton’s Tremec Magnum swap, we feel that burdening someone else with this manual-trans-disaster is a little unethical.

TABLE OF CONTENTS:

Episode 1: Our Modern Muscle Truck Project

Episode 2: Tremec Swap Parts List

Episode 3: The NV3500 Goes To The Scrap Pile (you’re currently on this page)

Episode 4: COMING SOON!

Episode 5: COMING SOON!