Box Rebuild

[adam87]

the box in my car is an r33 turbo box but from one to two its got a nice notch to it and if i dont be really careful itll crunch.

the rest of the gears are perfect in the way they feel.

is it possible to just rebuild/replace the old syncro's in that gear?

im not in a place thats easy to ask.

they keep telling me they just send the box away and get another back. but thats 1300ish and id prefer not to spend that in my current situation....

is it possible to just do the gear that needs doing?

thanks

[Duncan]

AFAIK you can just replace the 1 synchro that is crunching....but if one is gone the rest almost certainly are going or gone too. And there are bearings and seals that should be replaced too.

BTW 1300 sounds cheap to replace all the synchros and bearings. Or is that the cost to get another second handbox? If so I'd probably give it a miss, almost every box will have these issues to some extent by now.

You can just do what most people do - run the Redline Lightweight shockproof gear oil and slow down your gear changes a little....it won't fix anything but it might hide the problem for a few years.

[adam87]

AFAIK you can just replace the 1 synchro that is crunching....but if one is gone the rest almost certainly are going or gone too. And there are bearings and seals that should be replaced too.

BTW 1300 sounds cheap to replace all the synchros and bearings. Or is that the cost to get another second handbox? If so I'd probably give it a miss, almost every box will have these issues to some extent by now.

You can just do what most people do - run the Redline Lightweight shockproof gear oil and slow down your gear changes a little....it won't fix anything but it might hide the problem for a few years.

1300 is a reconditioned box

a second hand bax goes from about 300 to 600 here.

if shockproof is that good i might give it a go. althought i have heard some stories that some times it makes it worse.

[turboedsloth]

if thats a reco price i would be sending the box away to get done. the person doing the rebuild for you can check the synchros when its apart and replace more than one if required

[Spurdo]

i have the same gearbox and i personally rebuilt it a few months ago. trust me - if your going to replace one synchro you should replace them all, as well as all bearings in it. never trust a 2nd hand gearbox, you just have no way of knowing what condition its in. sure it could run fine now, but how long will that last? these gearboxes are all getting old now and i would put money on the fact that every one of them has seen a good bit of abuse over the years so i definately wouldnt waste my time with a 2nd hand box, you really are opening a can of worms if you do.

to get at the 1st/2nd gear synchros the whole box basically needs to be stripped which is a big job, and since you dont tend to strip your gearbox very often it would be a pretty dumb idea not to do the rest of them while your in there, as they are more than likely not far away from doing the same thing. be warned though, syncro's are expensive. they are likely to cost just as much or perhaps more than the labour charge to do it. over here in nz they were $1160 with trade discount. dont be suprised if you find them around $1000AUD.

see the reference picture attached this is of my actual gearbox during the rebuild. it points out where the synchros are in case your unfamiliar with what your up against. they are the bronze coloured rings highlighted by the arrows. if you dont have any experience with gearboxes do NOT attempt it yourself. even for me this thing was a bit of a nightmare

[bubba]

1300 is a reconditioned box

a second hand bax goes from about 300 to 600 here.

if shockproof is that good i might give it a go. althought i have heard some stories that some times it makes it worse.

What the hell? where is "here"???

My 25t box cost me $1500 2nd hand!!

[adam87]

i have the same gearbox and i personally rebuilt it a few months ago. trust me - if your going to replace one synchro you should replace them all, as well as all bearings in it. never trust a 2nd hand gearbox, you just have no way of knowing what condition its in. sure it could run fine now, but how long will that last? these gearboxes are all getting old now and i would put money on the fact that every one of them has seen a good bit of abuse over the years so i definately wouldnt waste my time with a 2nd hand box, you really are opening a can of worms if you do.

to get at the 1st/2nd gear synchros the whole box basically needs to be stripped which is a big job, and since you dont tend to strip your gearbox very often it would be a pretty dumb idea not to do the rest of them while your in there, as they are more than likely not far away from doing the same thing. be warned though, syncro's are expensive. they are likely to cost just as much or perhaps more than the labour charge to do it. over here in nz they were $1160 with trade discount. dont be suprised if you find them around $1000AUD.

see the reference picture attached this is of my actual gearbox during the rebuild. it points out where the synchros are in case your unfamiliar with what your up against. they are the bronze coloured rings highlighted by the arrows. if you dont have any experience with gearboxes do NOT attempt it yourself. even for me this thing was a bit of a nightmare

thanks for the info.

makes a bit more sense now.

What the hell? where is "here"???

My 25t box cost me $1500 2nd hand!!

im in japan.

there between 300 and 600 depending where you buy it and how much risk you take on it being good or bad.

to have a box changed at a shop here is 200-300 plus oil. if i was at home in aus id do it myself where here i cant which is a bugger.

[bubba]

im in japan.

there between 300 and 600 depending where you buy it and how much risk you take on it being good or bad.

to have a box changed at a shop here is 200-300 plus oil. if i was at home in aus id do it myself where here i cant which is a bugger.

Wow.

When I went to upgrade to a 25t box, it was $1500 for an unknown 2nd hand with no guarantees and that seems to be the going price everywhere over here.. occaisionally you'll see one for $1200 from a private seller.

It's quite annoying and disgusting but hey, what can you do? For $600 for the least risk I'd break 3 and replace until I felt I needed to rebuild one.

GTR boxes go for 600ish but a fair effort to turn it into rwd.

Good luck

[turboedsloth]

i bought an unknown condition 25t box over here in WA for $300. pulled it apart it had signs of water being inside but other than that im sticking a kit an sychros through it which cost twice the price of the box

[bubba]

i bought an unknown condition 25t box over here in WA for $300. pulled it apart it had signs of water being inside but other than that im sticking a kit an sychros through it which cost twice the price of the box

Are you doing it yourself?

[turboedsloth]

yeah i am.

[bubba]

yeah i am.

If it turns out alright would you be interested in doing more?

[Rowdyr32]

Can you lap in old syncro's in skyline box's. When I was in the Automotive industry. Lasted 4 weeks. One of the head mechanics said you can lap in some of the holden syncro's to make them work again. I guess they become glazed or the scores on them wear off?

Wondering if it works or if people have heard of it or tried?

[Mister25t]

I beadblasted the cones on the gears when I did mine, seems to shift nicer now but the clutch was rooted beforehand so hard to say...

[turboedsloth]

bubba, yeah i can do more for ya. am located in bunbury tho.

you can use fine valve lapping paste to lap the synchro back into the cone but if its to worn its just a waste of time and you'd be better off with new synchros

[bubba]

bubba, yeah i can do more for ya. am located in bunbury tho.

you can use fine valve lapping paste to lap the synchro back into the cone but if its to worn its just a waste of time and you'd be better off with new synchros

Cool, bunnos not really that far away

We'll see how long the current box lasts when the new engine/turbo setup is in.. the box has crunched 2nd a bit ever since I got it I got around that by just starting in 2nd instead of trying to hit 2nd