When the transmission pops out of gear (mostly 1st gear, but sometimes 2nd gear) ive been told that the syncros are bad, is that right?. were can i buy a rebuild kit and what is involved in fixing this problem ?.

The transmission is in an 85 4Runner.

 

The syncros might be bad but from my experience that’s not the end of your troubles. Once the gear is engaged the syncos really don't play a role in the gear operation. The gear popping out is most likely caused by either worn engagement teeth (dog teeth) on the gear or the shift collar. The worn parts could have been caused by worn syncos or aggressive driving. Could also be a bent shift fork but not as likely. Either way you’re going to need to split it open or buy a replacement.

 

I respectfully disagree.

Popping out of gear may be related to a very simple fix, or one more involved. The simple fix is replacing the shift bushing at the base of the shifter. Marlin has a harder compound bushing than factory which will last longer, but the factory unit is ok, made of a hard rubbery plastic compound. Certainly replace that first to see if it solves your problem.

If not, the W and R series transmissions show the symptoms of popping out of gear when longitudinal play in the mainshaft exceeds spec. This is caused by simple wear, primarily the bearings but also including the main bearing retaining plate as well as the other assemblies in the transmission, adding up.

I wrote an article some time ago about overhauling an R151 that now lives in the Chili's heart; the R151 is a bit different from yours but is essentially the same overhaul process. See if the overhaul described is too daunting - but be aware I had not overhauled a transmission prior to doing the article. It still works very well behind a 5VZ-FE, and this is a tranny that had seen significant abuse. It's a four-banana job, but the FSM is extremely good on providing guidance, and so is Marlin.

http://www.4x4wire.com/toyota/tech/r151f/

 

+1 on replace the bushing. It's the cheapest fix and best place to start.

 

Yep previous guys got it on the head

336 post's?
search yota tech
Or pirate
or TTORA
or marlin
then search

ive seen this tons around the web

http://www.marlincrawler.com/htm/transmission/3a.htm