Jump to content
SAU Community

Brand new RB25 big box notchy shifting

elohim_imanu
 Share

Recommended Posts

elohim_imanu Contributor

elohim_imanu

Posted
Posted

Just put in a brand new RB25DET big box, auto conversion.

Last time I drove manual was my 260Z, 15 years ago. But this box seems a bit notchy shifting up. Are new gearboxes like this? Do they have a break in period?

Also noticed a vibration on the clutch pedal when shifting close to red line. It is R34 box, with a pull clutch. I installed a new Nismo sports clutch with a slightly lighter flywheel.

I am running Penrite Pro Gear 75W-90.

Cheers

Duncan Grand Master

Duncan

Posted
Posted

Yes, a brand new box needs to wear in a little, and the "big box" is actually pretty beefy compared to most.

Just treat it nice for 500klm then change the oil, see if it improves

  • Like 1
  • 2 months later...
elohim_imanu Contributor

elohim_imanu

Posted
  • Author
Posted

Or to be a bit more specific. The 5 speed gearboxes that are built to take the RB25DET (turbo engines). The R33 GTS-T and the R34 GT-T came with them. Also the 300ZX Twin turbos, came with a similar gearset. A modern version is the CD009, which comes on the 350-370Z, 6 speed. They physically look stronger better made with extra gussets etc.

Basically these are the go to gearbox for people wanting a reliable gearbox for high HP applications. 

By the way I had mine checked by a local mechanic and he thinks it is fine, just needs some more miles to be clocked up on it.

The vibration was due the the Nismo pressure plate being out of balance. Had to pull it out and get it balanced along with the brand new billet steel flywheel. I would have thought they should be good from the factory already.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

(this is my opinion, please feel free to ignore) whatever you do, don't put Redline Shockproof into the box. Great for old, worn and thrashed boxes - has no place in new tight boxes.

Gee.. that sounded wrong.

  • Like 1
elohim_imanu Contributor

elohim_imanu

Posted
  • Author
Posted

I am running Penrite 85-90 full synthetic. 

He reckoned I should not play with difference oils. As I saw someone comment that they think the synchro's in these like mineral oil more. 

  • Like 1
BK Grand Master

BK

Posted
Posted

You beat me to it while I was typing this. Regarding mineral, Duncan mentioned somewhere in another thread about Terry at Award diff and gearbox recommending mineral with more frequent changes. I can definitely see the merit in that, getting rid of any excess metal in the box frequently. The same recommendation of changing gear oil after every event is for the same reason in dog engagement transmissions, to purge the metal shavings, regardless of oil type used. Obviously dog boxes shed more metal that synchro boxes but idea is the same for prevention of gear pitting and whatnot.

The main advantage of using synthetic is the higher operating temperature break down point of lubrication, leading to longer interval changes which can be good or bad depending on how frequently you change transmissions oil. We generally break in / flush the synchro boxes with Castrol VMX-M mineral. Actually in our white 32 it still has it in it after 2500km including a 1500km drive to Adelaide on a rebuilt box and the shift quality is excellent.

On 07/10/2021 at 1:36 PM, elohim_imanu said:

I am running Penrite 85-90 full synthetic. 

You mean

On 31/07/2021 at 7:32 PM, elohim_imanu said:

I am running Penrite Pro Gear 75W-90.

If so I hope it's this one

image.thumb.png.342671572481b0cec506a6d7f0478997.png

Not this one,  it's GL-5

image.thumb.png.470e401c968215c850d1f11f8c7d8585.png

On 07/10/2021 at 12:46 PM, Dose Pipe Sutututu said:

(this is my opinion, please feel free to ignore) whatever you do, don't put Redline Shockproof into the box. Great for old, worn and thrashed boxes - has no place in new tight boxes.

Gee.. that sounded wrong.

 I wanted to both like and laugh at that one 😄

elohim_imanu Contributor

elohim_imanu

Posted
  • Author
Posted

Actually I mean this one, after a check. (the 90 was for the diff) 🤣

SCA_342312_hi-res.thumb.jpg.084f040506b98b1720ab008d08b470ec.jpg

Is this bad?

I was surprised to see the amount of tiny steel shavings when I drained it after about 150ks, due to the clutch balance problem. Since I do not race and I am not pumping high HP through, it is this oil a good choice and how often do I change it? We are only talking a few thousand ks a year.

 

BK Grand Master

BK

Posted
Posted

Nah should be spot on 👍

Your box is new yes ? It will shed a fair bit from new, a balance problem wouldn't have had an influence on gear to gear mesh, which is where most if the material comes from.

Change intervals ? Change it in a year and see what it looks like. When new a good 500 -1000km first oil drop is generally the go.

  • Like 1

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • RP1421
      S15 Spec R

      By RP1421 · Posted

      As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • joshuaho96
      R32 GTS (RB20DE) Injectors Replacement

      By joshuaho96 · Posted

      I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • perry_r33
      R34 GTR Vspec Garage Sale - All must go!

      By perry_r33 · Posted

      Pm sent 
    • Robot
      Skyline v36 350GT sedan hunting on idle

      By Robot · Posted

      Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • GabsReDeal
      R32 GTS (RB20DE) Injectors Replacement

      By GabsReDeal · Posted

      After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...