5th Gear

[Arrbee]

Heys guys, just recently ive done an oil change on my RB20 gearbox. After the oil change, it won't go into 5th, it just grinds. What could be wrong ??? its not like 5th getrs thrashed like 1st and 2nd.

[BeEnAr]

not enough oil, or too much, or wrong type. What oil did you put in it, please don't say Magnatech! lol

[Arrbee]

Nah it was castrol oil. I used the full bottle pretty much. Im not too sure how much the gearbox contains.

[HI_PSI]

take the filler plug out if oil doesnt pour out or you cant feel any just below the plug level she aint full

[Arrbee]

Ok will give that a try.

[The Bogan]

Manual Gearbox: 2L (80w 90) or Castrol Castrol Syntrax 75W/90

[89CAL]

Youd be suprised what using the wrong oil does to gear changes, In my old car I used the wrong oil in my manual and it was an absolute pain in the ass to drive around with. New proper oil in and was way better. I think I use Syntrax in the skyline, it works pretty well, and isnt overly expensive

[Arrbee]

How many litres of oil is required for the gearbox ? or can i just pour the whole 4ltr bottle into it.

[errno]

How many litres of oil is required for the gearbox ? or can i just pour the whole 4ltr bottle into it.

mlr said above 2 litres

[Arrbee]

Just changed it all. Seems no different. Could it be selectors ? i highly doubt syncro's are rooted.

[BASHO]

R34GT-T gearbox 4.1 ltr.

Try Castrol VMX 80 if you want to use a good non syn or for syn - Castrol Syntrans 75X90 not Syntrax I think you may find that Syntrax is a hypoid (not 100%sure on that though.) anyway Syntrans is the one.

[BeEnAr]

Basho, he's got an RB20 gearbox, not same as a R34 GTT. But you are on the right track still, Syntrax is "especially designed" for transaxles with hypoid gears but can still be used. It has a higher viscosity range than Syntrans. Either way the Syntrax and Syntrans are usually around $20-$25 per L so not really cheap when compared to VMX-80 or Multitrax.

Main problem with the synthetic oils is their low temperature gear changes, they are a little stiff in the morning and take a few KM's to heat up and change smoothly.

Either way you still need to fill to the right level, car on level ground (so up on 4 stands or ramps, or on a hoist or over a pit) and fill from the drain hole until fluid starts to dribble out. In fact I think on the RB20 box you can just take out the gearstick from in the cabin and fill from in there. Over filling it won't hurt it at all, the gearbox has breather on it and the expanding gasses and oil will just vent through them, stinks like hell but that's about it.

Oh and DON'T GET TRANNY FLUID ON YOU! IT WILL TAKE WEEKS TO GET RID OF THE SMELL!

[Kinks]

I've never had a problem with gearbox or diff oil, it should only smell bad if it's been burnt by burnouts or drifting.

gearbox capacity is approx 4L, you should crack the fill plug (to make sure you can undo it), then undo the drain plug and drain it all. replace the drain plug and fill with new oil through the fill hole, until oil starts coming back out. let it settle for 30 seconds and then pump some more oil in there until it dribbles again and then replace the fill plug.

you can stick 4L of oil in the gearstick hole if you want but rather than get oil all over the cabin, the fill plug on mine was easy to get with a breaker bar so I did it that way. Then you know you've got the right amount in as well.

Beenar had it basically right but said "fill from the drain hole" by mistake

[BASHO]

I do all the work on my car alone and fill my gearbox from inside the engine bay with the aid of a funnel with a plastic tube extension , just jack up the filler hole side of the car , jack stand in , out with the filler plug first then the drain plug , oil into drain pan , out with jack stand , lower car , make sure oil drain is still over drain pan , leave for a half hour , jack up car again , in with jack stand , remove drained oil pan , put back in drain plug , tighten , back up top , wedge funnel into suitsble spot in engine bay with attached tube dangling , back under car , grab dangling tube shove in gearbox fill hole , make sure its wedged in , put drain pan back under fill hole just in case of a slip up , back up top fill up gearbox via funnel.

USE THE CORRECT MEASURED AMOUNT OF OIL AND YOU WONT OVERFILL .

All oil in OK , pull out funnel and hose wipe up few bits of oil you will inevitably get splashed around, back under car , in with fill plug , tighten , out with drain pan , wipe everything clean , out with jack stand , lower car, job done , have drink.

Edited May 15, 2010 by BASHO

[Arrbee]

Ok still no good. Ive just come to the conclusion that 5th is just screwed up. It just feels like it wont select in, and when i disengage the clutch it grind. Like usually when you change into gear it kinda pops/clicks in, with 5th it just goes into position and when disengage clutch it just grinds. Im done for, guess time to rebuild 5th ???