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Rb25det Gearbox Crunching Into 4th Gear

Guilt-Toy

By Guilt-Toy,
in Drivetrain and transmission

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Guilt-Toy Grand Master

Guilt-Toy

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Fixed my gearbox. as suspected the clips were in the oil.

We did not have to remove any of the gears, we were able to put the clips into the box without removing the hub! box is changing well now.

Also if you keep driving the box like this you will wear out the selector fork that moves the gears, i had to change to the spare one because this one was flogged out so if you have this problem you should fix it ASAP.

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Brandon Veteran

Brandon

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Nice... bookmarked!

I'll do this when I get a new clutch. Mine crunch as well but only shifting at high RPM. I suppose I'll just have to baby it when I'm in that RPM range in the mean time.

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Guilt-Toy Grand Master

Guilt-Toy

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very possible. also this crunch sounds different to a propper syncro crunch. a proper syncro crunch is very excessive and harsh where this is more of a notchy mini crunch as the gears are being selected.

i have and there wer no clips, but thats not to say the last owner found the clips before hand...
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ClutchBurndout-:( Grand Master

ClutchBurndout-:(

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very possible. also this crunch sounds different to a propper syncro crunch. a proper syncro crunch is very excessive and harsh where this is more of a notchy mini crunch as the gears are being selected.

hmm, well mine is very extended, not just a quick tap tap of the gears hitting inside the box, its more of a bzzzzzzzzzt on the rare occasion of shifting into 4th, usualy when giving it a bit more gas, i drove to work today with no crunches, and the box felt good, but sometimes theres a quick bzzzzzzzzt when shifting to 4th on the rare occasion.

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  • 10 months later...
fryzee Apprentice

fryzee

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i have only ever played with twin countershaft g/boxs was just about to attempt my syncros on my rb25 box.

just wondering if the timeing is still the same with the mark on the front counterahft drive gear (5th) and how or if the countershaft is shimmed up?

i havent looked at a manual or anything on light commertial g/boxes

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  • 3 months later...
want_33 Community Regular

want_33

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i have found one of these clips in my oil recently after my gearbox got stuck in 4th. Had to pull box out as it refused to come out of gear. once we got it on the ground out of the car it slipped out of gear and has been fine since we put it back in the car. I never use 4th tho as its a drift car and only see's 2nd and 3rd.

Reason it got stuck in 4th was i was loading it onto trailer and the shifter felt weird and stiff, i just pulled it into gear to see what was going on and it got stuck there.

Should i put this fix on the urgent list?

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  • 3 years later...
AMR33 Mentor

AMR33

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Hey all, digging up this thread as I'm now having this problem after tracking the car.

Fixed my gearbox. as suspected the clips were in the oil.

We did not have to remove any of the gears, we were able to put the clips into the box without removing the hub! box is changing well now.

Also if you keep driving the box like this you will wear out the selector fork that moves the gears, i had to change to the spare one because this one was flogged out so if you have this problem you should fix it ASAP.

Can you post some pictures how you did this without changing the hub mate?

And is 36209-70L20 the right part number for these? And should I order 3 from nissan?

Cheers

Amir

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skylinekrille Apprentice

skylinekrille

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Hi do you have any tip on how to remove the 5th gear bushing? In the service manual its a pic of som sort of cylinder tool with 3 bolts to use along with a puller. That special bushing tool seems to be very rare

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turboedsloth Grand Master

turboedsloth

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I made a plate up that sits under the centre plate, and a jig that presses on both mainshaft and cluster. I made a tool to pull the bush off but its a shrink fit and is really tight. The press works heaps better

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skylinekrille Apprentice

skylinekrille

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Okej will try make some special jig like that. Or do you even need to remove the bush to be able to change all sync rings? Looking at the pictures on this thread it looks like he just knocked the main shaft out of the center plate without removing the Bush on the sub shaft

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