Hello All,

For the past 6 years, I have been driving my 86 4WD Pickup (with the W56-B manual transmission) with a slight whine in 5th gear. It was a junkyard tranny that I got for around 500 bucks installed, so it was a great investment and has got close to 300k miles on it. Well recently the 5th gear whine has turned into what I would call a grinding, gnarly “death yodel”, and has me ready for another stop-gap junkyard tranny swap to buy me a little time for a proper rebuild by Marlin in the next couple of years. I’ve invested several grand in this truck over the past 2 years and want to keep it forever if possible.

I picked up another junkyard transmission/transfer case for 400 bucks that supposedly has only about 140k miles on it, and would like to do a reseal and see how long I can go before I send this failing one off to MC. I also have bought a bunch of new OEM seals and gaskets to hopefully keep the gear oil on the inside - as it is currently leaking from the input shaft seal and where tranny meets the transfer case (where there are missing bolts).

I’ve done some minor work on the truck over the years, but I am by no means a mechanic, and have never touched a motor or transmission beyond fluids, spark plugs, beater hoses, etc. Since I am trying to teach myself how to do more and more to repair this truck, I will be documenting this for future reference, and for any other DIY newbies that want to do a very basic reseal and replace of a W56. The junkyard transmission is sitting in my shed waiting to be resealed.

What I would like to know is any tips or tricks on how to properly replace the input and output shaft seals for the tranny, as well as any important gaskets and seals for the transfer case. I have downloaded the Toyota W-series transmission overhaul doc, but this is quite complicated and doesn’t focus on the process of installing the seals, just the gears/synchros/mechanical parts.

Here is the list of the parts that I have collected, they are pretty much all OEM except for the few heavy duty MC parts (output shaft seal & shifter seats/sockets). I have replaced the clutch and all related hydraulics with AISIN/OEM parts, as well as the flywheel (Marlin Crawler heavy duty) within the past 10k miles.

Parts (Transmission)
04331-20050 - Seal & Gasket Kit (OEM)
Heavy Duty Shifter Seats (Marlin Crawler)
Heavy Duty Shifter Sockets (Marlin Crawler)
Heavy Duty Rear Output Seal (Marlin Crawler)

Parts (Transfer Case)
3614335010 - GASKET, TRANSFER CASE, FRONT
3614635021 - GASKET, TRANSFER REDUCTION CASE
9031132009 - Transfer Case Input Shaft Seal
9031248001 - Transfer Case Input Shaft Seal

^^^ Which One/Both? ^^^

9043018008 - Transfer Case Shift Shaft Seal (Front, Rear) - 2
9031138016 - Transfer Case Output Shaft Seal

I am going to fill with 75W-90 redline gear oil. Also, Toyota recommends Three Bond, should I use this?

*The only oddities I noticed was 2 different input shaft seals on the transfer case, but only 1 part number for the TC output shaft seals. Are these identical? Also, I’d like to get my hands on the 4/5 missing bolts where the TC attaches to the tranny. Any idea of exact specs on these?

Thanks for reading my novel, did I mention that I have a bit of ADD/OCD?

Thanks in advance.

-Dude

 

I can help with part numbers, but you might consider going deeper.
140k miles is a significant amount. Maybe the trans bearings have been replaced once before, but on anything from a wrecking yard it's best to assume not.
You can get bearing kits with koyo and Naichi bearings at a very fair price. That noise you heard from 5th gear was probably your countershaft bearings beginning to fail. As the bearing failure worsened the poor meshing of the gears turned the whine to a clunk. This is a very common repair on your series truck.
You have a few choices. You can rebuild yourself, it's not hard if you're patient and methodical. Or you can pay someone to do it. If you go that route, I'd recommend supplying the bearings and seals to the tech to make sure you get quality parts.
If you decide you might want to undertake it yourself a few tools besides sockets and wrenches are needed. Most are very handy to have regardless, a few will be rather specialized. But none a terribly expensive, and some may be found at your local parts store loaner program.