4L60E & 700R4 Delayed Engagements Gear Train Issues

All right, so now I'll talk about delayed engagements as it relates to transmissions.

So when you have a delayed engagement, delayed engagement is characterized by when you put the vehicle into gear, into drive or reverse, nothing happens for like maybe five seconds, 10 seconds, or similar amount of time.

And then it'll then start to move.

If your delayed engagement feels like the vehicle's locked up, like something's just preventing it from moving as if,

Maybe somebody stuck a wheel chalk underneath one of the wheels.

What is probably happening is the rear gear train is starting to break up.

So...

engage and apply and then power flows through that applied element um through the uh forward sprag and out through to the gear train so what i'm going to demonstrate here is applicable to the front planetary carrier group ring gear and sun gear and the principles are the same but basically if you know in a normal situation

Your sun gear and your planetary will rotate and mesh like so inside the ring gear as the output shaft is spinning.

Now, in a delayed engagement situation, what's happening is your teeth are starting to break up.

So they might break up with the ring gear, the planetary carriers.

know gear teeth are interfering mesh so when these are trying to mesh together if a piece of gear tooth gets lodged in here it will seize up right it'll it'll essentially act as a you know as a I guess what do you call it it's like sticking a stick through the spoke of a running bicycle you're a moving bicycle wheel and it just locks it up and

So oftentimes you'll have to throw the vehicle either out of reverse or into drive or vice versa.

And then the carrier will stop spinning, you know, in the opposite direction.

And that will oftentimes free up that, you know, gear tooth, that piece of gear tooth that's wedging itself in between the planetary gears and the ring gear or the sun gear.

Now, in some of my teardown videos, 4L60Es, I talk about missing reverse second and fourth due to the sunshell fracturing or breaking up.

And that can happen where the sunshell, the splines here in the neck are stripped out or the neck separates from the body.

If that happens, you're gonna miss reverse, you're gonna miss second, and you're gonna miss fourth.

You're not gonna have any of those gears.

The same conditions can be sourced to gear train failure as well.

so when it comes to preventing gear train failure the number one way to do that is simply keep up your fluid changes the other thing too is when you have the transmission overhauled make sure that the shop flushes your lines in your cooler or coolers if you have an external transmission cooler because if there's a restriction in those lines then fluid lubrication fluid is not going to make it to the gear train components and

you know if it's real bad then you'll burn up the entire back half of the transmission uh grenading it completely so what'll happen there is the um you know the planet and the sun gear will weld themselves together into the ring gear and you'll have a complete seizure and i've seen it where i've taken um you know these three parts

that you flush those lines, flush the cooler, and also at the same time, if the transmission's leaking, make sure that you seal up the leak, whether it's a pan gasket or if you have to pull the transmission because the converter seal on the front's leaking out of the pump.

Either way, if you lose enough fluid, you won't have sufficient lubrication and it'll cause gear train failure.

And that is the, primarily speaking, the number one reason why these gears break up in an otherwise normal daily driver type application.

In a race application or high performance, real high RPMs, I mean, that's a whole different animal, especially with a high stall converter, more heat's generated.

And if you don't have additional cooling capacity in the form of a deep pan or indoor engine,

You know, the largest external cooler you can fit inside the engine bay, then you also run the risk of burning up the transmission, especially the gear train.