Wits' End Toyota JDM Winch Rebuild Project
PART ONE: The Winch
We've been having some fun lately with all sorts of winches. But to date we've never done an OEM Toyota electric winch rebuild. This customer's truck finally gave us the opportunity to totally nerd out on the winch. This is the winch that typically came with JDM 81 Series Land Cruisers found on trucks in Japan. The ones we see now are typically past the Federal 25 year rule or were previously Canadian vehicles. With the age of these right hand driver diesels we expect to see more come stateside.
There were two types of winches that Toyota produced for the Land Cruiser, either the PTO which which is all mechanical or the electric winch driven off an electric gear reduction motor. On this JDM 81 Series its the electric variant. This truck arrived to us with the winch never working for the customer. Quick initial test did not bode well.
The first thing to take a look at was what was under the plastic cover. Once off you get access to the LOCK/FREE spool handle, which is missing, and the 6-pin connector for the Toyota Winch Controller. For reference, 3600Kg is 7936lb so we can call it an 8000lb winch for simplicity. Should be plenty of power for the majority of extractions.
One of the things that was noticed was that the steel cable had some looping up top which looks like it wasn't spooled in properly after its last use. This is a piece of evidence that would lead us to its ultimate failure.
First step is getting the winch off the truck. This is pretty straight forward. A couple of bolts and the front bumper comes off in one piece. From there the Winch Support Front Crossmember needed to come off. Also no biggie, just a few bolts. Once its off you can get a clear view of the entire winch assembly. A couple of bolts removed from the bottom, plus a few battery cables removed from the solenoids, and the winch comes out. Its a pretty heavy beast. Once its reassembled it'll get weighed with the new winch rope.
With the winch out of the truck we can start inspecting it for damage and start the disassembly to see where else the damage can be found. The winch motor itself kinds looks like an oversize gear reduction starter motor with two solenoids. Personally I've never see this type of motor design before so its exciting to get to see it up close and personal. We will do further inspections on this later. For now we just want to test the circuits while we have it on the bench to test. The LOCK/FREE spool handle is stuck solid. That'll take some work to get working.
First thing is first, we ran through the circuits to see if the controller even worked. It seems the controller has some funkiness on one circuit so we will deal with that later. But the controller itself seems to be ok. Its cracked in a few places but that can be fixed as well. But generally we were happy to see the controller light up.
Once power is confirmed it was time to start getting things torn apart to figure out the damage. It didn't take long.
PART TWO: The Tear Down
The main motor is only held in by three bolts so simple to remove. The shaft engagement is a surprising but typical Lovejoy type connection. Its just a machined shaft into a matching slot on the motor. The thing that was unusual is the total engagement was only about 1/8" but there is nearly 3/4" available. Odd, why was it only getting a small amount of engagement? This caused the shaft to be rounded and the slot to be damaged at the coupling edge. Something caused the motor and drum to be pulled away from each other. Hmm...
Removing the drum from the Winch End Bracket Sub-Assembly was just a matter of prying the drum away from the sub-assembly. All of the rust build up gave it a little trouble but it came loose.
Once apart we found another piece of evidence, the quad seal was broken. Whoops. This would help explain the water intrusion. Then we removed the shim from the clutch side and noticed another piece of damage evidence. The disc was very damaged and it sits directly next to the seal that was cut. Ol now we know the shim cut into the seal. But what damaged the steel shim?
PART THREE: The Culprit
Well all the evidence of damage all pointed to this. The winch sub-assembly has plenty of scoring from where the steel cable slipped the drum and landed in between the sub-assembly and the motor. There was so much torque on the cable as it was spooling in on the wrong side of the drum that it wedged itself into the space it wasn't supposed to be and thus pushed the winch motor about 5/8" out from the drum. This is why the shaft was barely touching the motor slot and why it got rounded out. So the why is solved. Now its time to finish tearing down and getting to rebuilding the winch and making it better.
PART FOUR: More Tear Down
Now that the drum and motor are separated its time to go through the clutch and the planetary gears. The clutch is a very interesting set up. It uses a small clutch pack and a camming lobe bearing stop that acts as the brake for the winch. You can only go one way with how it turns. If there is ANY slippage on the shaft then the camming bearing will stop it immediately. Its a very slick design.
Yeah this isn't looking good at any angle. Everything that could go wrong did go wrong. The back plate for the planetary gears was cracked open and the only fluid inside was water and rust. If there was any ATF in this winch's life, it exited years ago.
PART FIVE: Time for a Bath, Acid Bath
There are a few ways to remove rust. Some are more reliable than others and some quicker than others. Due to the amount of rust on ALL of the steel parts we opted for Muriatic Acid (36% Hydrochloric Acid. Each piece was wrapped in a steel wire to be able to lift from the plastic bucket. Muriatic Acid was poured into the bucket VERY slowly to prevent splashing and only enough to cover the parts. We only needed to give it MAYBE five minutes before it was taken out of the bucket and quickly dunked into a bucket of water and then flushed.
From there the washed parts were immediately dunked in a bath of fresh ATF (transmission fluid) and then scrubbed further with various brushes and wire wheels. The sucky thing is there is a lot of galvanic corrosion. Kinda of a bummer to see where it absolutely wasn't expected. Likely it doesn't seem like there is damage on any surfaces that are interacting with each other. But we will know more once it gets reassembled.
All of the aluminum chunks of the winch is going out to get vapor honed so that we have some cleaned up pieces to work with. It will help get the rust out of the inside of these pieces.
All the ATF soaking will prevent any rust flashing. But lots of sanding and wire wheeling was needed to get these pieces not look so angry. Hmm
Now the shaft assembly is pre-assembled so that we don't lose track of how it all goes back together.
Had to order up some shims, some o-rings and a seal. The parts needed were:
• (2) Ring, WinchSpacer, Winch Drum, No.1 (1) Spacer, Winch Drum, No.1 Seal, Gear Case Cover Oil Shoe, Brake Gasket, Winch Gear Case Cover