Hello, I am new to this forum and owning a vehicle in general so bear with me.

I recently purchased a 1986, 2l diesel 4x4, 5spd manual transmission Toyota, this is my first vehicle and I am less than mechanically knowledgeable. 3rd gear is giving me problems right now and I would love some educated guesses on what the problem could be, when I shift into 3rd while coasting the engine braking works and all seems fine but as soon as I touch the gas it knocks it back in to neutral and starts to grind if I try and put it back in 3rd.

 

Check the basics.. If you hols the shifter in 3rd doea it stay? Shifter not hitting dash, shift lever not hitting body. Pull the stick shift inspect the bushing for wear.

​​​​​​if none of that leads anywhere like a bad mount or bushing it's time to pull and RnR the transmission.