the trans has 183k on it. (GSLSE) and you cant shift at a high rpm without grinding it, (which by that time the revs dropped). It shifts fine under normal driving. Im thinking the syncrhos are going bad. but it does it in everygear like that. And the clutch is going bad as well from wear and tear and age. Does it sound like dying syncrhos?

and where can i get new ones to rebuild the trans?

 

Honestly sounds more like a clutch issue but I'm not positive on this one, check your clutch fluid levels.

Does the trans crunch when downshifting into 2nd or any other gear?

Does the trans whine in any gear?

 

Yeah, if your clutch is weak then that will add to the grinding.

If the tranny is the issue, you might want to try this tip from "how to hotrod and race your Datsun"... Use a 50/50 mix of gear lube and ATF in the tranny. The atf has detergents that will clean out the synchros and improve shifting. Works like a charm too. The two major Datsun race teams run this full time.

 

Sounds like the trans to me....

You can try to put in good gear oil. I've used redline and had it work wonders. My friend used the really thick stuff in his MR2, the stuff that looks like strawberry syrup, and it toatly fixed his up. I used it in my last FC, helped a lot.

But I had to change the trans in my FB cause I was on the freway and wanted to down shift into third, it took a bit more effort than usual, but no grinding.... after that I had to drive for 30 miles while redlining cause I couldn't shift into anything but 1st or 3rd gear.
That sucked.

 

most likely new clutch time..but like what was said..check those fluids
my tranny was noisy before putting RP in it..now it's almost like new

 

If the problem is similiar in all gears, start with the hydraulics, then move on to the clutch itself. Flush and fill of the tranny would not hurt either, before you pull the clutch.

If we had redlines similiar to piston engines, our synchros would last much longer. With age they do not like high rpm shifts.

 

Ken's suggestion worked for me. I figured the synchros were worn out after 150K, but aparently they were just full of crud.

While I wouldn't rule out a bad clutch, I tend to think clutch problems would give you shifting trouble at any RPM.

 

Wow, I feel lucky. My car has a bit more mileage than that and only 2nd gear grinds (upshifting and downshifting into it). Could be that trans was heavily abused. But, also give the clutch a look and replace it. Also, in regards about the revs always dropping, just train yourself to tap the gas pedal again once you get it into gear to bring it back up to ensure a smooth transistion. I do that everytime I'm bringing it into 2nd gear.

Do your gears grind even when you first drive the car off or only when the transmission starts to warm up? When I first drive off, 2nd gear is usually gentler until the tranny gets warmed up, then it starts to show its grinding side. You could always get your tranny rebuilt if it comes to that. Should only cost $1500.

 

I got 2 Gsl-se tranny spares... PM me if interested!

 

If your clutch hydraulic system is weak, then you might not be fully disengaging when trying to shift. That could cause some grinding. Otherwise, consider what I posted earlier.

 

This is a different sympton, you appear to have a synchro going out, time to find another trans, sorry.