Rb25det Gearbox

[jase444]

hey i really need to kno wats goin on with my gearbox when i drive normal 1, 2, 3 are good but when i change to 4 it crunches when i put it in. but it doesnt do it all the time

help please

[blow thru]

hey i really need to kno wats goin on with my gearbox when i drive normal 1, 2, 3 are good but when i change to 4 it crunches when i put it in. but it doesnt do it all the time

help please

Mate i had the same problem when i brought my 32 it was pretty good through all gears but would crunch into 5th, so i drained all the oil an put in redline lightweight shockproof oil, this oil really grabs onto the syncros after about 50 or so k's it came good, box now feels an sounds new nice smooth changes. This was rb20. Not cheap oil but awesome

[sneaky1]

treat it nice. mine was doin it to then one day drivin it nicely 2nd gear went on a holiday to never return .

i put redline in it and it did help but not enough. and everyone thinks rb25 boxes are unbreakable.

now to rebuilding it. hmmmm

[skylinekid]

well changing into forth just hold the stick back with light pressure dont force it in just let the synchro do its work... yes it is a slow change but its wat ya gotta do generally for the time being..

[Jez13]

Hi Jase,

I have exactly the same problem with mine (r32 GTR). 4th crunches only when I am giving it heavy throttle, but not full thrashing. I have a feeling its from flat changing by the previous owner. My suggestion is when going from third to forth > engage clutch then move to nuetral > release clutch > engage clutch again and then put into fourth. This should take all the load of the box and make a smooth change. Option 2 is to rebuild and to shift a bit slower in future.

[jase444]

thanks for the advice i have bought another box and will swap it when i get a chance but i think i will put some redline to i can get a bit more life outta this one