I was driving to work the Monday morning thru the nice snow on the highway, doing 45 mph in 5th gear and instantly just reved up. Now come Friday after the car finally melted all the **** off it, still won't shift to 5th gear. When I put it in 5th gear you can feel it go past the synchro but nothing there. It had the S20 transmission in it.
Do these gears have a known problem to break? I have read the S40 will bolt up, but what changes have to be made to do it, if any?

 

Is there any MTF in the transmission? Did you replace the MTF with fresh Honda MTF?

 

There is MTF in it yes, but it is a little low. I haven't added to it yet for the chance that it needs rebuild or replacement.

 

My EM1 trans use to pop out and not want to go into 5th because it was low on MTF. My 86 prelude literally melted teeth off of both 5th gears because it was low on MTF.

 

How do you know its low? 5spd transmissions don't have dipsticks, if your transmission had a leak than that could have caused it to grind and damage the gears/synchros.

 

Get the car on a lift or level it off the ground with jack strands. then pull the fill plug and if you no fluid comes out, or isn't right below the fill plug its low. If it is low drain it to see how bad it is contaminated, then fill with new fluid until it just starts to come out of the fill plug.