Gears

[MistR33td]

hey guys i got a R33 and evertime i try n change into 4th at about 4 thousand revs, so by the time u change its about 3500, the gear crunches, but it goes in, just crunches....just wanna kno wot i can do to fix it or it just goes away (doubt that, but u can always hope, lol). cheers for any advice guys

[heslo]

Could try chucking in some Redline Shockproof into the gearbox, of course, dumping your old oil first. I had a 1st to 2nd gear crunch and this seemed to fix it for me. Made my gear changes feel a lot more smoother too. Well worht it I reckon and should help you with your problem

[NeverNaughty]

The crunchin when changing gears is the synchros which require friction to work correctly. While redline shockproof is an excellent gear oil for protecting the actual gears in a gearbox it isnt the best for the synchros. Castrol VMX 80 gear oil is a better option. The are a couple tricks that can be performed to reduce some build up of material on the synchros and reduce glazing. First one is to fill the gear box with a kero oil mix and run the gearbox through the gears with the wheels off the ground so there is no load. Dont do it for too long as it will eventually where the gears. The second trick is with the gearstick in neutral, the engine running and the clutch engage apply pressure to the gearstick towards the problem gear. Dont push it so hard that it drops into gear. These will only provide minor improvments. Nissan gearboxes are renowned for synchro problems and the only true solution is to replace them

[Cubes]

Nevernaughty..

I can say I've heard of the engine running clutch engaged and apply pressure to the problem gear.

I have recently started having issues with 4th gear when changing up from 6000rpm so I may give that ago. Failing that I will throw some synthetic castrol gear oil through it. The synth castrol stuff works well.

[Mike_]

I thought that method was designed to "re-bed" the synchros. With the clutch pedal DISengaged, and the car at standstill, rev the enging to around 2000 and hold it there. Then pushthe gear knob down to fourth. It won't slip in.

I vaguely remember hearing something about doing it 20 times for 5 seconds, or 5 times for 20 seconds, but I cant remember which.

Disclaimer: You didn't hear this from me...

[Snotballs]

My gearbox was fine, and after i changed my transmission oil with shell synthetic oil the following day my second gear started to crunch. I thought it was just maybe thicker oil than what was in before (dont know what was in before). I took to workshop and they replaced with lubrimax agritrans however it still crunches in the morning. Its weird how it just started happening after i changed my oil, it was fine before....

so should i just try a different oil ? is fixing syncros big job ?

[sky30]

I have used redline lightweight shockproof oil in 2 of my gearboxes that had crunching syncros, after putting in the redline, the crunching was gone. Really is amazing oil, i cant recommend it enough.

[vange]

my car has the same problem when i go into 4th gear, and 5th. same problem when going into first when gearing down. i have to stop in nutral for a split second for it to go in ok. som1 told me its a skyline thing.

[MistR33td]

cheers for ur help guys, think i'll be tryint that redline transmission oil...hope it works.