Fourth gear grind

[Sleepergm]

Anyone else have a grinding issue changing from 5th to 4th gear. I have no issues 3rd to 4th and 4th to 5th. But the car seems to grind a little when I do 5th to 4th … 

 

is this a common issue? Had it from the last owner. Bit annoying as I can’t hard shift down. Feels like I have to push a little to the left to get it smoother into gear. 
 

thanks 

[GTSBoy]

Why would you ever need to "hard change down" from 5th to 4th? Any time you're in 5th and need serious accel, you're looking to go down to 3rd or maybe even 2nd, anyway.

Just treat your 30 year old gearbox with some respect.

[The Bogan]

Down shifting = Right gear, right RPM, right road speed!

Try rev matching on the down shift

[joshuaho96]

4 hours ago, Sleepergm said:

Anyone else have a grinding issue changing from 5th to 4th gear. I have no issues 3rd to 4th and 4th to 5th. But the car seems to grind a little when I do 5th to 4th … 

 

is this a common issue? Had it from the last owner. Bit annoying as I can’t hard shift down. Feels like I have to push a little to the left to get it smoother into gear. 
 

thanks 

Change the transmission fluid. I would try Motorcraft XT-M5-QS if you have it in your area for a reasonable price. Also, double check your clutch is fully disengaging. If you are not pushing the clutch pedal to the floor fully for every shift now is the time to start. Make sure the clutch is fully bled. The damper line requires two distinct bleed points to be purged of air or it will not disengage the clutch properly. If either hydraulic cylinders input or output are losing hydraulic pressure in their seals/leaking you can have problems like this.

If you've ruled out everything else then the most likely explanation is the synchros are worn and you need to double clutch the shift or rebuild/replace the transmission. The transfer case is discontinued FYI so you may want to rebuild it while you're in there too. If the chain stretches past spec it can do a ton of damage.

[Sleepergm]

25 minutes ago, joshuaho96 said:

Change the transmission fluid. I would try Motorcraft XT-M5-QS if you have it in your area for a reasonable price. Also, double check your clutch is fully disengaging. If you are not pushing the clutch pedal to the floor fully for every shift now is the time to start. Make sure the clutch is fully bled. The damper line requires two distinct bleed points to be purged of air or it will not disengage the clutch properly. If either hydraulic cylinders input or output are losing hydraulic pressure in their seals/leaking you can have problems like this.

If you've ruled out everything else then the most likely explanation is the synchros are worn and you need to double clutch the shift or rebuild/replace the transmission. The transfer case is discontinued FYI so you may want to rebuild it while you're in there too. If the chain stretches past spec it can do a ton of damage.

Yes I think we changed out the transmission fluid as I had a leak last year so we changed out the seals also. Need to check. 
 

I should have said just change from 5th to 4th gear … down shift. There’s a grind. 
 

I have a new clutch X clutch … but as I said all the changes in other gears are fine. 

[joshuaho96]

35 minutes ago, Sleepergm said:

Yes I think we changed out the transmission fluid as I had a leak last year so we changed out the seals also. Need to check. 
 

I should have said just change from 5th to 4th gear … down shift. There’s a grind. 
 

I have a new clutch X clutch … but as I said all the changes in other gears are fine. 

How fast are you doing the downshift? 4th gear was revised multiple times until 1998 to fix this issue. Synchro clips can fall out, synchros can wear. Most likely you're looking at a new transmission unfortunately. If you need to limp it until then double clutch downshifts into 4th.

[GTSBoy]

Meh. Every single gear in my gearbox will crunch. I've been treating it nicely for >12 years now.

[Duncan]

Most likely the 4th gear synchros (and probably others) are worn. Redline lightweight shockproof gear oil has been the go to for masking that issue a bit, it is very common.

The only real solution is to fit the R33 series 3 gearbox bits in a full rebuild....or accept it is not a new car and shift slower

[joshuaho96]

11 hours ago, GTSBoy said:

Meh. Every single gear in my gearbox will crunch. I've been treating it nicely for >12 years now.

I've worked around a crunchy/grindy gearbox for so long now that track instructors note how I have absolutely awful shifting habits. S L O W shifts and then blipping the throttle even on upshifts out of habit. My vote is R33 series 3 gearbox, those are still readily available and relatively cheap.

Edited 4 hours ago by joshuaho96

[blind_elk]

The gearbox in my R32 GTS4 (now with RB25DET) has just over 300k on it . Life includes some track time. Has had one change of oil in its lifetime. I rev match on down changes.

I don't have any problems with synchros or gear crunching.