bridgeboys3

91 240sx hatch. Transmission started to grind and shake. Pulled the transmission out the fork for the throw out bearing was off. Fixed that put the transmission back in and guess what? Transmission is doing the same thing but worse... Can someone give me a little incite on what the issue may be?
Thanks

Odysseus Prime

I assume you are the same one who posted on Yahoo?

Did it do this before the 6 puck clutch / flywheel was installed?

And did the throw out bearing look in good condition?

ravenracer

Thank you for your professionalism in the Tech section.

bridgeboys3

The transmission worked fine before install. And yea that was me aha.. But the throw out bearing is brand new and it was fine

Odysseus Prime

Is it grinding between shifts? Grinding in every gear - down and upshifting? Like almost locking you out of gears?

Try pumping the clutch twice (double clutching lol) between shifts. Since it worked fine before and this propblem just sprung up on you, I would say that there might be a small leak on the clutch master cylinder and air got into the lines. Maybe on the inside where the shaft goes into it. I've seen 240's leak there before. It sounds like it is not building enough pressure to push the slave all the way out.

And like I asked the other guy. What gear oil did you put in the tranny itself? GL-4 - GL-5? GL-5 is known to eat up the syncros in 240's. Pretty sure that's what happened to mine when I had the first KA Tranny in it with GL-5. 1st, 2nd, and 3rd became hard to get in gear.


As for the shaking, I am not sure. Maybe the tranny mount / driveshaft middle joint mount is not 100% tight?(unless you have a 1 piece). Those are the only things I can think that would cause a 240 tranny to shake.

bridgeboys3

Well it has a new tranny mount and new clutch master cylinder. Got both when the trans was pulled out. And for the grinding it grinds going into every gear and when you take your foot off of the gas petal it grinds while rolling

Odysseus Prime

I would at least re-bleed the slave cylinder and adjust the clutch master shaft to see if that helps the grinding. If it does, you obviously had air in the lines somehow. Maybe check the hard lines (unless you have braided lines) and look for any abnormalities or very small leaks around the ends.

Kind of stumped. I would take a guess and say your syncros are going bad...OR- you're not building enough pressure going into the slave cylinder and it is not pushing the throwout bearing into the pressure plate enough to fully disengage the clutch, so it grinds. (be it the actual pressure or there is something wrong with the throwout bearing/fork assembly--I know you said, you looked at it. I am just thinking of what would cause grinding)

Other than that, I am out of ideas at the moment.


And did you unbolt the driveshaft from the differential end or unbolt it in half? I've read on Zilvia of people having driveshaft balance issues after splitting the stock driveshaft in half. That would cause some vibrations if it's unbalanced.
That is the last thing I can think of as far as shaking/vibrations.


Good luck

bridgeboys3

Thanks