G52 tranny questions

[El Jefe]

Fresh meat here... and I'm elbow deep into the g52 tranny from my 84 4x4 pickup(180k mi). After a lot of deliberation I have decided to rebuild the tranny myself, I have time on my side, solid mechanical aptitude, and the guts to give it a try. So riddle me this...
Background:  A few years back fifth gear began making a whining sound, due to economic issues and such I just turned the radio up at highway speed. Now after a recent road trip all the rest of the gears, except fourth, have taken on a similar note, and I decided to do something about it.
I have seen some bits and pieces about a common problem with G52 fifth gear, and a fix it kit, but nothing definitive, such as a source for the kit or a solid explanation of the problem.
I have come to the conclusion that the universal gear noise is caused by a worn out input bearing, but of course I could be wrong.
In addition I have seen different opinions about break in procedures, mineral oil for the first 10K, then go synthetic. Or just go top shelf synthetic right out the gate...  Also a friend told me to not reuse the old snap rings, does anyone have an experienced take on this?

At this point I have it down to the intermediate plate with all the gears still on it, shafts and forks removed. There is no sign of gear damage, just fine metal shavings. I assume I will come across any bearing wear as I check play and what not in the next couple days.
I have a MC minor rebuild kit, FSM, and have sourced new snap rings and pretty much all the internals I may need, so I'm just looking for thoughts on what I have mentioned or any other good ideas about the G52.

Thanks folks.
   

[2manytoys]

Give Marlin's shop a call.

[Mad Dog]

Fresh meat here... and I'm elbow deep into the g52 tranny from my 84 4x4 pickup(180k mi). After a lot of deliberation I have decided to rebuild the tranny myself, I have time on my side, solid mechanical aptitude, and the guts to give it a try. So riddle me this...
Background:  A few years back fifth gear began making a whining sound, due to economic issues and such I just turned the radio up at highway speed. Now after a recent road trip all the rest of the gears, except fourth, have taken on a similar note, and I decided to do something about it.
I have seen some bits and pieces about a common problem with G52 fifth gear, and a fix it kit, but nothing definitive, such as a source for the kit or a solid explanation of the problem.
I have come to the conclusion that the universal gear noise is caused by a worn out input

bearing, but of course I could be wrong.
In addition I have seen different opinions about break in procedures, mineral oil for the first 10K, then go synthetic. Or just go top shelf synthetic right out the gate...  Also a friend told me to not reuse the old snap rings, does anyone have an experienced take on this?

At this point I have it down to the intermediate plate with all the gears still on it, shafts and forks removed. There is no sign of gear damage, just fine metal shavings. I assume I will come across any bearing wear as I check play and what not in the next couple days.
I have a MC minor rebuild kit, FSM, and have sourced new snap rings and pretty much all the internals I may need, so I'm just looking for thoughts on what I have mentioned or any other good ideas about the G52.

Thanks folks.
   

Neat, The noise in all the gears except fourt is for sure the bearings

As far as fifth gear breaking I consulted with other rebuilders and seems the cause of the problem is most likely lugging the vehicle in fifth , this is a very common problem in not only Toyota but Mitsubshis, Toyo Koyo transmissions, Mazda,

Keep out of overdrive unless at free way speeds, and no low range operation in 5 th gear,

but sounds like you have a good handle on this thing and carry on, be sure to check the bearing retainer for the main shaft bearing, they like to wear out just a bit and allows the shafts to walk back and forth, pops the thing out of gear,

[emsvitil]

I agree with the bearings being worn out (input, mainshaft and countershaft primarily)

If you're changing the synchros don't start with synthetic oil.

[spuds015]

never reuse the snap rings, get all new ones

[El Jefe]

Thanks folks!  The deeper I get the better it looks, everything is in great shape exept the main bearing, there is an obvious break inside the bearing.

Any thoughts about excessive wear on the t-case? is it next to go due to the vibrations? Should I start thinking about rebuilding it as well to save the trouble later?