Repeat after me, I hate automatics, I hate automatics, I hate automatics. This truck had a weird shifting issue when I bought it and since I’ve spent most of my life driving a manual transmission. I had a tough time figuring out there was something wrong with it. I thought maybe it was low on fluid, or maybe it needed a change and a new filter. How do magnets work ?Early on the only thing I figured out for sure was that the Montero needed a transmission mount. So after a bunch of wasted time, which included dropping the pan and cleaning it, It still didn’t shift right. The Montero would hang in 1st then sort of jump to 3rd and getting the trans to kick down into 2nd would let the engine rev out to redline. Finally it dawned on me after dropping the transmission pan again, that it was filled with clutch material after only a few 100 miles. It was obvious now that the second gear clutches were totally burnt. The 4 speed auto was really a 3 speed with a huge gap. It was a frustrating, because for the most part it would drive around town just fine. I actually developed a driving style that avoided any hard kick downs into 2nd, which to my credit is difficult in a truck that has the acceleration of a glacier. The worst thing to deal with however was climbing any type of steep grades. The truck just wouldn’t do anything but the smallest of hills. As soon as the road began to incline, the speed would continue to drop and the engine temp would start to rise dangerously or driving on flat roads the transmission temp light would come on. Of course I was told on the internet that the Aisin Warner 4 speeds these trucks use are supposed to be rock solid, well I found the 1% of shitty ones. The Original Garbage Montero transmission was toasted at 245k miles. Was it from abuse? No maintenance? Wrong fluid? I don’t know really, except that the truck was fucked and if I had any hope of getting this thing onto a trail, I had to swap the trans.
I was able to pick up a used transmission with about 100k less miles than the broken one for fairly short money on ebay. Local junk yards kept trying to sell me 4 cylinder transmissions. Now I’ll admit, I’ve got a leg up on most DIY mechanics. My dad bought a lift for his garage about 12 years ago and he also loves buying tools, to my benefit. Well, lucky for me, his plow truck needed a t-case and instead of us breaking our backs hucking the t/case up and down. My dad bought really nice transmission jack. At least the transmission job on the Montero wouldn’t be a back breaker, but that doesn’t mean it still wasn’t a pain in the ass.
When you break it down, the transmission is really a simple job, drop the drive shafts, remove the starter, drop the Y pipe of the exhaust, remove the trans cooler lines, unplug any connections, drop the crossmember and take it out right? Sort of, you see the t-case hangs off the back of the Montero transmission about 4 inches over the torsion bar crossmember. Monteros have IFS if you aren’t familiar with them and the crossmember that holds the rear most part of the torsion bars is welded into the two main frame rails. This means that you can’t simply remove the transmission mount and lower the transmission down and out. Once the transmission is unbolted, which is easier said than done. Reaching the top bolts required some 3 foot extensions and careful tilting of the engine with a bottle jack. After the transmission was unbolted, it had to slide to the rear and separate from the engine. Then be tilted upwards slightly to the rear. Once you’ve cleared the engine, it’s time to tilt the front of the transmission down to begin the tricky operation of removing it from the chassis. However, as soon as you can access the bellhousing it is incredibly important to secure the torque converter in place. With it secured, that a 20 lb fluid filled doughnut doesn’t come crashing out onto the floor. Maneuvering the transmission out of the truck felt like guiding a freighter out of port and it would have been miserable without a stand up transmission jack. At minimum you would need a floor jack with a transmission adapter if you had to do this in a driveway.
Once it was out, it was a breeze, the t-case swapped over and everything matched like it should. The oil pan in the junkyard transmission was clean and didn’t have much in the way of metal shavings stuck to the magnets.
I however, still don’t fully understand automatics, I assume they work on magic. One thing my dad did remind me of is that you have make sure the torque converter is seated. They can become unseated during shipping or removal. Basically you just turn and push the damn thing into the bellhousing till it slides home on the input shaft. I did that a bunch and it didn’t really move and farther in and the torque converter looked like the transmission that just came out.
We got the damn transmission all the up into position. Moved it into mount up with the engine and it was a half an inch shy seating, it just wouldn’t go. This is where it gets stupid, two rational people, who have a good understanding of cars, could not get the transmission to seat. Finally out of sheer exhaustion of just trying to force it and being dumbfounded. I stopped, regrouped and tried seating the torque converter again. I Pushed the transmission back a bit and reached up into the bellhousing with my hands and began to push and turn. That stupid torque converter slide all the way into the bellhousing with such little effort, it was like when a safecracker finds the combination “click”. “Fuck yes!” I yelled. Two hours of stupidly struggling with it and now, I had the transmission in place in about 2 mins. That feeling of success was was a hell of a motivator and I had the rest of the truck back together after about another two hours. A quick fill with the proper ATF fluid and I’ll be damned, with a working 2nd gear this truck isn’t half bad. Acceleration has improved from glacial to steadily advancing lava flow.