What Tranny Fluid to Use?

[Mr Camouflage]

Apart from the grade of oil you put in, what else was written on the bottle.

Some types of gear oil (specifically, some types of synthetic diff oil) is not suited to synchro gearboxes, as its too slippery for the syncros (or in the case of lsds the clutches) to work correctly. I believe the synchros rely on friction to work correctly.

[ChrisA]

Since this problem started I have changed the clutch and pressure plate and all the plastic bushings around the shifter lever itself.

Okay, I'm no tranny expert but he said he changed the clutch and pressure plate "since this problem started". Could he have a clutch related problem which is causing the hard shifting? Not getting enough release which is causing some kind of drag. I dont believe it would be fluid related.

FWIW,

Chris

[=Resurected280=]

Im not sure what was written on the bottle but I could find out, I think I still have it some where. It might be syntetic actually which would explain why it might be too slippery. So far as the clutch goes ChrisA, I was also thinking that maybe the clutch was not working properly (it'd never been replaced before I owned the car) but after I replaced it there was no difference in the shifting quality.

I think im going to try a lighter weight non sythetic oil this weekend, I'll definetly let everyone know how it turns out. :-)

[dogma420]

I would say this ISN'T fluid related--I would say it is clutch related....if the clutch isn't being disengaged all the way, it would show up first at the 1st to 2nd shift point....

? How is the shift from neutral to 1st?

? How is the shift from neutral to reverse?

If either of these are harder than they should be, this could be because the clutch needs to be adjusted; if the slave is auto adjust, adjust at the clutch pedal...

If you changed your oil well after driving your vehicle after the clutch components have been replaced (say you didn't, cause that's not what I would've done! and I'm a normal grease monkey) then we'll be back to square one....

ok, now I see it's a 78 280z....If your fluid was changed when you did the clutch items, I would definitely adjust at the clutch pedal a little bit....have the piston push a little more in the fully engaged position (with your foot OFF the clutch)...just a micro adjustment at a time, like quarter to half a turn...its really sensitive...I had to do this on my 72 when I went with a 78 5 speed and installed all new clutch hardware (including a new master/slave and steel braided)....I had hard shifts from n-1st and 1st-2nd also n-reverse...once adjusted at the pedal (the thingy that pushes on the piston is adjustable) my rig has ran beautifully!

Hope this helps!

[=Resurected280=]

Thank you dogma240 this does sound like its going to help!!!

The shift from neutral to first is fine so long as you are going VERY slow, under 5 mph usually, and reverse I've never had any kind of problem with. The fluid was changed before the clutch was changed.

BTW I am I am running the same transmission set up as you and I am using the stock dimensions for the clutch pedal adjustment that I pulled out of my Datsun shop manual.