my 1990 mazda b2600i 4x4

Hey everybody, I am new to these forums so sorry if I do anything wrong.. anyways I made this post for questions I have and to show you all my truck which I love!!! Well I just recently traded my car for my truck and while I was driving I noticed it grinded shifting into 3rd and 4th gear only so that means I need new synchronizers right?? How do I go about this my dad knows a lot about vehicles but says he doesn't really want to mess with this.. would this require the whole tranny taken apart or can you fix it from the top? I'm only 16 by the way so don't have a lot of money but I do work. I will really appreciate your guyses help!!!

Welcome to the forum! Where do you call home?
Complete dis-assembly of the transmission is required to replace the synchro's.

Welcome to the forum!

Thanks guys! Would you recommend doing it yourself or taking it to a mechanic?

And I'm from a small town called Denton, Ks

Im sure its not hard but ive never messed with a tranny. Lol. Thats funny

Transmissions can be intimidating.

Watch this. Pause at 26:49.

The brass/bronze parts are the synchronizers.
Further teardown is obviously necessary to replace them. If you endeavor replacing them, I suggest setting up a video camera and recording teardown, so you have a reference for reassembly.
It's moderately difficult job for a novice. It would be wise to have someone with some experience assisting you.

Hey guys... How do I change my transmission fluid on my truck?

Remove the drain plug to drain it. Reinstall plug.
Pull the fill plug on the side of the transmission.
Also pull the shift lever. Fill through the shift lever hole until fluid runs out the fill plug.
Reinstall plug and shift lever.

That what I did and it only filled the transfer case and not the transmission at all so I had to drain the transfer case... I just got more oil for it