Jump to content
SAU Community

Recommended Posts

Guys;

I've had my gearbox rebuilt (was catching on 1-2 too often) with new synchros and bearings and I'm running Motul oil. Problem is that it still sometimes catches 1-2 and 2-3, doesn't matter whether it's cold, hot, hi rpm or low rpm. Only way to guarantee it won't catch is to pause briefly during the shift but that means losing pace. 3-4, 4-3, 3-2 are no problem.

Tried different oil and Slick 50 but no change. I know that heavy duty (compared to most other cars) gearboxes like the GTR tend to be a bit clunky due to the sheer size etc of the internals and I don't expect it to be ever be as smooth as a Camry or WRX ie 'hot knife through butter, but I'm not happy about this happening in mine so soon after a rebuld. It doesn't get thrashed and I expected that the shift might be heavy but still smooth with no catching - ever. Rebuild was done by Award in Sydney.

Is this just the way they are or should a rebuilt box be like silk? Thanks for any feedback.

Regards

Link to comment
https://www.sau.com.au/forums/topic/68896-gearbox-shift-quality-r32-gtr/
Share on other sites

A couple of things come to mind.

Firstly, make sure the clutch is not dragging.

Secondly, the viscosity of the oil in your box will make a big difference to the shift quality & to the synchro's. First stop is to make sure you have the right grade.

The second step is to use the ubiquitous Redline oil. This often helps old/tired boxes, but I'm not sure about new ones.

Beyond that it may require the gearbox out again.

Just out of interest in regards to viscosity.. too viscous means you tend to drag stuff right? and if it's too thin what happens then?

I've been running redline shockproof heavy in my box and now it's seized in 3rd so I'm wondering if that may have done it?

Just out of interest in regards to viscosity.. too viscous means you tend to drag stuff right? and if it's too thin what happens then?

I've been running redline shockproof heavy in my box and now it's seized in 3rd so I'm wondering if that may have done it?

Too thin means Crunch!

Guys;

I've had my gearbox rebuilt (was catching on 1-2 too often) with new synchros and bearings and I'm running Motul oil. Problem is that it still sometimes catches 1-2 and 2-3, doesn't matter whether it's cold, hot, hi rpm or low rpm. Only way to guarantee it won't catch is to pause briefly during the shift but that means losing pace. 3-4, 4-3, 3-2 are no problem.  

Tried different oil and Slick 50 but no change. I know that heavy duty (compared to most other cars) gearboxes like the GTR tend to be a bit clunky due to the sheer size etc of the internals and I don't expect it to be ever be as smooth as a Camry or WRX ie 'hot knife through butter, but I'm not happy about this happening in mine so soon after a rebuld. It doesn't get thrashed and I expected  that the shift might be heavy but still smooth with no catching - ever. Rebuild was done by Award in Sydney.

Is this just the way they are or should a rebuilt box be like silk? Thanks for any feedback.

Regards

Mmmmmm, gearboxes do take time to run in and you haven't mentioned how many K's it done since the gearbox was rebuilt. Personally i don't find GTR gearboxes to be overly heavy or slow to shift. We use exclusively Castrol synthetic lubricants (Syntrax 75W90 in the gearbox) so I have no experience with other oils.

If it were me, I would have a talk to Award and see what they have to say:cheers:

Thanks SK;

It's probably done about 6000km since the rebuild. I'll talk to them, have already spoken to the shop that took it out and they were full of words like 'size of internal parts, mass, old technology' etc but they didn't give me a definitive answer.

In particular I don't see why it would do it sometimes and not others.

Regards

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • That looks good, but I think you're going to need much beefier side skirts now.
    • They are daft and there's a reason it never caught on. Steering feel? We don't need no stinking steering feel!
    • I gotta pull you up on this. It's driving me crazy. A shutter is something that closes, like over a window or in a cmera. The word you want is shudder. That LSD is clearly f**ked. Take it to a diff shop and get it disassembled and examined by an expert. YOu might have plates welded together or something equally crazy.
    • Define "starting to fail". Wy not just rebuild them?
    • Check the Nistune doco. There are a few assumptions being made here that might not be valid. I will list the things that occur to me: Base map. Base map for what? Base map for Z32? Then the cranking pulse width is probably wrong for an RB25. The extra 500cc of capacity might well be enough to prevent it from catching. Base map for RB25? I don't think you can load one of those into a Z32. You have to just make the settings correct for an RB25 in the Z32 base map. That is either K or the TIM to get the pulsewidth right. Loom. You bought a loom for an RB. And you plugged it into a Z32 ECU. Did you make sure that any iwre differences were swapped. From memory, there's at least a couple. And as per the others, I would suggest making sure that the fuel pressure is correct while cranking and that the injectors are actually flowing as expected. They really must come out and go on the bench, unless you do find that you have messed up as per above points. I would also suggest watching in Nistune to make sure that everything is reading correctly. That the correct binary flags are raised at the right time (like the crank signal), that there's no stupid values in K or TIM. That you have not got mismatched firmware for the ECU and/or a wrong image loaded.
×
×
  • Create New...