Gearbox grinding into 4th..
 

Hi all,

Looking for thoughts on this. Have a Hawk WRX and gearbox always been notchy.. Been told by few people that is just how they are...
Recently it has really resisted going into 4th gear at higher revs. say anything about 4000rpm. It resists going in but if you do it will give a good old crunch. Lower revs up to about 3000rpm you wouldn't even know there was any kind of issue.

I have read on various places this can be rectified by changing gearbox oil. I have just purchased a load of Motul Gear 300 to go in it. Am I wasting my time (and money) as gearbox is about to give up or worth doing to try it?

Car has about 65k on the clock and running 320bhp 350ft-lb for nearly a year. was stock power before that. I don't launch it and tbh hardly take it over 3000rpm day to day. never done a track day in it.
Just be amazed if the clutch out lives the gearbox lol...

I have been running 285/350 for 50k no issues still original clutch and box, I have gulf completion oil in the gearbox. The clutch is as heavy as but still got a good bite.

I am afraid yours sounds like worn syncro on 4th. I would put the £50 for the oil on a new box, and do the clutch while at it. its going to hurt, not much change out of £800.

If you try matching the revs on your gearchange ie the syncro would not need to work it will rule this out as it could be the clutch, hope this helps

Thanks for the reply. Gearbox has never been great tbh. first thing in the morning I sometimes have to put it in 1st to free things up before it will go into reverse. Worst case I sometimes have to put in first and lift clutch a little and then it will go into reverse.
This does make me wonder if the clutch isn't fully engaging?! No slipping I am aware of but pedal is rather stiff. (just thought that was what they were like)


Maybe the clutch is worth considering?


I have already bought the oil so tempted to change it anyway.

Had mine since new box is much a muchness fitted a CDF quick shift made changes a bit heavier but never had to engage first and lift to engage reverse. Deffo sound like clutch related and still sound like a syncro issue on 4th. I am old school can drive a car without a clutch from starting in 1st and matching revs up and down the box, had many a old Ford with snapped clutch cable. Try matching the revs on 4th.

I have done many things to try and improve the gear change feeling. Group-N mount, polyurethane cross member bushes, Polyurethane gear linkage support bar bush...
I also have a quick shifter as I found the stock shifter imprecise.

I am no stranger to crappy old ford's etc. either.. Also being a motorcyclist I am no stranger to doing clutch-less shifts so fairly sure it isn't my 'technique'
Think I will just go ahead and do the oil.. Shall come back and update tomorrow hopefully.

Oil change was interesting.. Oil came out black as if it were from the engine! never seen gearbox oil so black. I last changed it about 18 months ago, probably no more than 10k miles... I was actually shocked how dark it was.

New oil in and it is like a different gearbox. All changes are much smoother and although I have had no cause to get up into 6-7000rpm area even at 5000rpm is goes into all gears without a crunch.. Looking hopeful it has helped.

I do wonder about the clutch though. Is there any easy way to check its state of life? Pedal is as I say always been heavy so thinking it could be past its best.

hmm. went out at lunch and gave it some abuse. gears better to engage there is no doubt in that. BUT 4th still crunches at higher revs. :(

Box is a TY754VG7AA-T2 Are there any 'upgrade' options keeping it 5 speed or is 6 speed the way to go? and if so what is involved in going 6 speed? Would it be more cost effective having the box rebuilt or any way I can get in there to check/repair anything?

cheers.

chrunching when changing gear is a worn/broken syncro.
6 speed swap would involve only changing box+support, driveshaft and shifter mechanism. 5 spd flywheel and clutch can be used, as does the 5spd starter.

Cheers. I think I may have sorted it.. As a last attempt I decided to swap back to the OEM gear shift. looks to have cured it! Going to change the UJ bushes as well to rule that out.

linkage issues is very common which is why we offer various upgrades to suit most options........

https://www.facebook.com/media/set/?...1523135&type=3

thanks for the reply.. I have heard you guys do some UJ upgrades. I looked on your website but could not see any listed.. Do I need to call to purchase some from you?

At work so cannot see FB link at the moment.

I already have upgraded the support bar bush to a Poly one. How much for UJ bushes?
thanks,

just call the office and we'll sort..........