advice on syncro grinding solutions pls.

[jim martin]

96 Legacy wagon, 5 speed, 102K miles. The gears grind when downshifting to 4th & 3rd-which I do a lot of in Colorado! They also grind sometimes shifting from 3rd to 4th. These are not horrible grinds but you can hear & feel them. 2 different repair places have offered possible solutions. First is to drain out all old tranny fluid & replace it with slippery stuff called "syncro shift", and leave it there. Cost is ~$130.00. 2nd option is from the other repair shop and they'll put in some sort of fluid, I drive around for 500 miles or so & then they drain & replace w/ new tranny fluid. Cost ~$40.

 

Anybody deal with this? THX

[bratman2]

My 87 Brat had similar problems a couple of years ago. I first tried adjusting out with the clutch cable to no avail. Second I tried Pennzoil gear oil change, no help. Third was Mobile 1 gear oil which made it way worse. Hated dumping that out after less than a month. Redline synthetic gear oil fixed mine. Do a search for Redline's website and email them to find out which gear oil is best for the newer Legacy as it may not be the same for a Brat. You should easily be able to do this yourself for way less than the lowest price you have obtained. i believe this will help, Glenn Taylor.

[gbhrps]

I follow the Nissan 300ZX forum and a lot of drivers have complained about a grinding from 3rd to 4th. Every time a pile of answers come back to use Redline (I believe its MT90) in the gearbox...and everytime the original thread starter comes back to thank everyone and say it solved his problem or significantly reduced it. I haven't needed to try it myself on my own Z, but thought I'd let you know. Good Luck!

[meep]

modify shifting technique.

 

1: ensure you use the absolute least amount of force on the stick. Over time it will adjust and improve.

 

2: press ever so lightly, wait for it to start to move into gear and THEN press it through the gate

 

3: rev-match first while in neutral and clutch released (foot off), then snick it in using 2 above.

 

4: always pause for a split second in N before entering the next gear.

 

Effects are not immediate, but you'll start to feel a difference in a couple 100 miles, big differences.

 

Mike

[bratman2]

Meep is right that slowing down the shifts will help but my old 87 brat had got to the point that it would still lightily grind going from third to fourth no matter how careful I was. Redline did cure it completely within a couple of hundred miles. I don't believe any slippery stuff additive will help, this was the problem w/ mobile1 gear oil, too slippery to allow the gears to engage smoothily. Glenn Taylor.

[sprintman]

Redline 75W90NS fixed mine. RL 75W90 (not NS) in the diff, D4ATF in the p/s too. Not cheap but worth it IMO.

[meep]

The newer mobile 1 MT lube is really good. I dumped it in our newly acquired well-worn miata 5spd. Second was so shot the synchros literally would not allow engagement--- and still often does not until warm. Adding M1 lube make a big difference, using the tricks above in combination has almost returned it to "normal," though it's still touchy.

 

Mike

[Setright]

Redline NS is a tiny bit better than Mobil 1. I think going to MTL/MT90/Shockproof should be left until you have tried one of these first.