Taking out Transmission to dos
 

Hello There! Quick info, this post is regarding a 1992 4Runner with a 3VZE motor and R150 transmission.

I just dropped my transmission so as to fix some oil leaks under the car (oil pan gasket and main seal and others) and was wondering if there are any recommendations on best practices to change/ replace some things like seals and bearings while the transmission is out. I am planning on changing the pilot bearing and throwout bearing, clutch and pressure plate, main seal. I saw in my service manual a front bearing? Could someone tell me what that is/ should i replace it? never worked on this transmission before (only ever dropped a transmission with a friend once before and he did most of the work.) Thank you so much in advance!

The R150 is one of Toyota's best transmissions. Others may disagree, but my thought is that, if it is shifting well, running smooth and quiet, and not leaking, I wouldn't touch it. I would just drain it and refill it with some Redline GL-4 gear oil (GL-4 will shift smoother than the more common GL-5), and continue to run it. If the transmission has always been running filled with clean, uncontaminated gear oil, it's likely it looks like new inside.

Gear boxes don't really wear out on any definite schedule. They typically fail either due to mechanical abuse, or due to lack of, or contaminated, lubricant.

I'm with RJR here for the most part. I had my tranny (a W56) out not long ago and wondered the same thing, should I do a rebuild on it or not. Most opinions seem to be that if it shifts ok, then no reason to mess with it. Mine has about 194k miles on it and really was not giving me any trouble. Also, rebuilding a tranny typically takes some long jaw bearing pullers that most people don't just have. So, for me, rather than risk all that downtime and finding the right tools, I finally decided just to leave mine alone, I did however change the front and rear seals because those are pretty easy to get to.

No harm in changing the tcase fluid as well, especially if you don't know the history. Use GL-4 or 5 in that. There are synchros in the chain drive case, but they don't get used much, so the GL-5 isn't a problem.

Chances are the leaking oil pan and rear seal have caused all of your mess. Oil leaks up front get driven back by the air flow and just cover everything. Makes it look like your truck is one massive oil spill, when really it's only a small leak.

If you also drain/fill the diffs, make sure you use GL-5. The ring and pinion require that.

Thanks RJR! Im thinking the oil pan is the biggest cluprit, but inside the bell housing is a mess. I checked transmission fluid levels before we pulled it and it doesnt seem like its leaking from there so i hope its mostly just the pan and the main seal. Rear diff looks like its also leaking, but that one im just gonna clean and then see if its really leaking or just splashback from farther forward