4th to 6th grind!

[KyleR]

Hey, after going for a long drive on Sunday I noticed when changing from 4th to 6th the gears would grind pretty bad unless I let the revs drop before moving into gear. Now after searching the forum i've pretty much diagnosed it as the syncro problem. But can't seem to find rough prices as to how much it would cost to get fixed. The car is a 04 GT with 67k miles that I bought last Saturday, so I really don't have the cash lying around to throw a new gearbox in and there is no warranty currently on the car.

 

Thanks

[DannyBoy]

My synchros are on the way out as well so i've been looking at options recently. I got a quote of £500-£600 for a basic refurb and synchro replacement including removing and refitting the gearbox. Personally I'm waiting on finding a later model gearbox for a while yet before I try a refurb. The problem is that the '03-'04 boxes are just poorly designed with inherently weak synchros so i'm not convinced that refurbing it is really going to make £600 worth of difference.

 

I've been looking for a later box for a while now with not much luck, but if you can get one the CD009 boxes (2006 cars) are the best that will fit on the DE engine, but the CD008 (2005 cars) boxes are supposed to be significantly better as well, and are easier to find.

 

hope that helps,

 

DB

[KyleR]

Thanks Danny, so how much are you expecting to pay for another gearbox?

[DannyBoy]

I've found a few CD008 boxes in the UK for around the £500 mark with reasonable mileage on them, but the only CD009 boxes i've seen have been A) not in the UK and around the £900 mark. Bear in mind it's going to be many hundreds on top of that to fit as I think it's about a 4-5 hour job (someone may need to correct me on that).

 

DB

[Dave J]

Guys, before you buy another gearbox try flushing the box oil and refill with Redline Heavy Duty Shockproof gear oil. I've used this many times especially on R32 GTR and also R34 GTR boxes. It's a little stiff from cold but really does the job and is far cheaper and easier than changing the box

Dave.

[DannyBoy]

Guys, before you buy another gearbox try flushing the box oil and refill with Redline Heavy Duty Shockproof gear oil. I've used this many times especially on R32 GTR and also R34 GTR boxes. It's a little stiff from cold but really does the job and is far cheaper and easier than changing the box

Dave.

 

Box had new OEM oil and molyslip additive about 1000 miles ago, made a difference but the synchros are just too far gone for it to cure it completely.

 

DB

[Ekona]

What happens if you go 4 -> 5 -> 6 rather than block changing?

 

If it's okay doing it that way, then you know what my suggestion is going to be... FWIW my old car used to make odd noises when block changing too, so I just stopped doing it.

[KyleR]

It did grind once going into 5th from 4th but most of the time it's ok, if I let the revs drop out before moving into 6th it's fine 100% of the time... so far!

 

I know I could easily let the revs drop or change up through the gears 1 at a time, but it's a pretty big habit to try and break. Plus, who is to say it won't get worse and grind in every gear.

 

I'll maybe get Nissan to change out the gear oil at the next service which is only a few weeks away to see if that makes much of a change.

[Lexx]

my opinion on this.....

 

surely if it doesn't grind when you go up the gears in order, but does when you box change, then regardless of how hard a habit it is to break then you should break it.

If you continue to do it, you could cause more damage to the synchro's.

 

 

Add some molyslip to the gearbox oil too

[KyleR]

my opinion on this.....

 

surely if it doesn't grind when you go up the gears in order, but does when you box change, then regardless of how hard a habit it is to break then you should break it.

If you continue to do it, you could cause more damage to the synchro's.

 

 

Add some molyslip to the gearbox oil too

 

But as I said in another post, Lex, is has grinded going into 5th from 4th before, only once or twice, but that may be due to me not doing it much. Currently the double clutch/rev drop method has been working, and since i'm obviously not in a hurry if skipping gears it shouldn't be a problem.