Rb20 Gearbox Jammed

[liampire]

I recently removed the front main seal of my gearbox to replace gasket as it was leaking. When it was off i saw three pin like rods (which i now know are the ends of the selecting rods). I have pushed the bottom one in with my finger out of curiosity and it pushed in. Not thinking anything of it I put everything back together and went to select gears and now it seems like the gearbox is stuck in first gear. However the position of the gear selector in the cabin appears to be in neutral. I drove the car and you cannot select any gears but can drive it in 1st gear. I have unbolted a sensor on the gearbox and was able to push the rod back into place (the one that I had pushed in) but it made no difference and still stuck in first.

Has anyone experienced this before?

Here is a picture. Main seal is removed. The rod at the bottom is the one that has been pushed in.

Thanks in advance,

Liam.

[2LV8ETR]

Dude! What were you thinking???

Unless you know what you're doing (Somehow I don't think so), you'll need to split the box to sort it out.

[battery]

bit off topic but where did you get a new gasket from and how much?

[SteveL]

I recently removed the front main seal of my gearbox to replace gasket as it was leaking. When it was off i saw three pin like rods (which i now know are the ends of the selecting rods). I have pushed the bottom one in with my finger out of curiosity and it pushed in. Not thinking anything of it I put everything back together and went to select gears and now it seems like the gearbox is stuck in first gear. However the position of the gear selector in the cabin appears to be in neutral. I drove the car and you cannot select any gears but can drive it in 1st gear. I have unbolted a sensor on the gearbox and was able to push the rod back into place (the one that I had pushed in) but it made no difference and still stuck in first.

Almost certainly the striker arm is out of place in relation to the engagement strikers on the selector rods. Also the selector rod interlock balls are what is preventing you selecting other gears.

Only way to fix it is to drop the extension housing, reposition the selector rods to their correct location (ie gearbox in neutral for re-assembly purposes) and then bolt up the extension housing so that the striker arm engages the selector rod strikers correctly.

[SteveL]

bit off topic but where did you get a new gasket from and how much?

Nissan will have it and your probably looking at $20 or so. The seal should be replaced as well, but that can be obtained from any bearing specialist for a few $$.

[liampire]

SteveL - Thanks for your input. I have the car up on jacks ready to take the box out tomorrow so I can sort it all out. The anticipation for this car is intense as it will be putting out some decent numbers on standard rb20 engine (230-240kw). I am so frustrated that I can't select gears!

battery - I always make my own gaskets. A roll of gasket paper costs $8 and getting genuine stuff is way too expensive and too far for me to drive and I believe my handmade gaskets are better anyway. See picture below for the front main seal gasket. It's .8mm jointing paper. Use with gasket sealer and you have perfect seal.

2LV8ETR - I am not a mechanic but learn quickly through disassembly and diagrams.

[2LV8ETR]

2LV8ETR - I am not a mechanic but learn quickly through disassembly and diagrams.

Then go for it man.

Just be careful to use the correct sealant on the sandwich plate. DO NOT make a gasket!

[battery]

battery - I always make my own gaskets. A roll of gasket paper costs $8 and getting genuine stuff is way too expensive and too far for me to drive and I believe my handmade gaskets are better anyway. See picture below for the front main seal gasket. It's .8mm jointing paper. Use with gasket sealer and you have perfect seal.

thats awesome, what do you use to cut them out? and where do you get the paper from?

[SteveL]

I always make my own gaskets. A roll of gasket paper costs $8 and getting genuine stuff is way too expensive and too far for me to drive and I believe my handmade gaskets are better anyway. See picture below for the front main seal gasket. It's .8mm jointing paper. Use with gasket sealer and you have perfect seal.

That's admirable and in 95% of cases probably perfectly fine, but in this case the thickness of the gasket is important because it influences the end float of the countershaft of these gearboxes. There's a procedure for selecting the correct countershaft shim, which relies on the thickness of the gasket (amongst other things).

Also the genuine gasket has extra sealer pre-bonded to the faces (you can see it as thick 'lines' running around the surface of the gasket). You need to add the cost of your sealer to the cost of your gasket paper.

I'm not criticizing you - I make my own gaskets sometimes as well - I'm just saying that in this case at least it's not as clear cut as you make out.

[liampire]

thats awesome, what do you use to cut them out? and where do you get the paper from?

Supercheap auto, it's $8. Put of few dabs of super glue to the part and then stick the paper to it so it doesn't move around. Supercheap also sells a set of scalpals for $4 which is super sharp so you can cut it properly. Get some gasket sealer which is $14 and you are good to go. .8mm gasket paper is fine as it does compress once the part is all bolted in. Don't listen to what ppl say on these forums about it having to be the right size and this and that cos i've used this on plenty of cars and have stopped leaks good and proper and been on over a year and is perfect. People have made gaskets from kellogs cornflakes boxes and made a perfect seal. Mechanical stuff is not what it seems to be talked up to be