Gearbox rebuild

[JimX]

I'm getting a bit sick of a couple of my gears crunching. Namely, 1st -> 2nd crunches when cold, and 4th -> 5th crunches hot or cold (not every time though).

How hard is it to replace the synchros yourself? And is that all you need to replace to stop the crunching? Would anything else be worn out and need replacing? If it's too hard to do at home, what would a workshop charge for a rebuild, assuming I just hand them the box and not the whole car? (saving some labour costs).

I've never dropped a gearbox out myself, but I don't imagine it will be too difficult, just time consuming. Any tips on how to do it? (R33).

[Bleach1]

I have major crunching problems from 3rd to 4th when it is hot or cold. I also have a slight crunch from 1st to 2nd when cold. It should only be the synchro but the synchro sleeve can be damaged as well but its not very common. Try some good new gearbox oil first or some treatment.

I havent taken the box apart on a skyline but i have taken one out and they are big heavy buggers. I have done synchros on other cars and it isnt to hard. Some boxes you need to use a press to get bearings and so on off to replace synchros. I dont know about the skyline. Sorry to be not alot of help really...

[Lenno]

JimX...

I have the exact problems as you describe, please keep us all posted on the outcome.

As for pulling the box out ya self..dont do it unless you got a hoist

thanks...lenno

[2fardown]

I had my gearbox recond under warranty. They replaced 2nd and 3rd synchros. The 2nd and 3rd synchros are a dual synchro. The total cost ended up being $1900 that included new bearings.

The mechanic said it was a pretty big job and it took the guys that did it (mechanic couldnt do it, took it to a gearbox specialist) about 5 days or something. He mentioned something about a lot of adjusting.

Anyway it's something I wouldn't attempt by yourself if you don't have any prior knowledge of replacing synchros. Don't expect too much change out of $2000.

[JimX]

Bleach1, sorry I forgot to mention that the first thing I did when I got the car was put in some Heavyweight Shockproof oil. 2nd and 5th gears used to crunch every time, but after putting the new stuff in the box is where it's at now.

Lenno, why would I need a hoist? Surely the box isn't that heavy that 2 people can't lift it? My plan was to put the car on ramps, then use a trolley jack to slowly lower it onto a wheeled dolly or something then lift it up onto the workbench or ute (depending on if I can work on it myself or not). Or can you use the hoist somehow to make it easier to drop down?

2fardown, I think Nismogirl got hers done for $1100. Keep in mind though that both yours and hers included the workshop doing the removing and replacing of the box, which I would think is half the labour cost or more. I'm aiming to keep it under a grand.

Just one more question - what are the long term consequences of letting the crunching go without repair? Will it damage the whole gearbox, or just the synchros and dog gears used to engage the other gears?

[Sumo]

JimX: we dropped the box out of a R33 and we used a pit, I know for sure now that me and my mate struggled when the box come out.... It was one big heavy bitch. I reckon trying to hold it whilst laying down would be harder...

Sumo

[JimX]

Well that's why I was going to use the trolley jack Although I'd still have to think about how to balance it well enough on the trolley jack until we could get it out from under the car. Maybe 2 trolley jacks with a piece of 2 by 4 between them?

[Lenno]

jimx...

A hoist is easy because 3 people can stand up and jiggle the box out with ease. same goes for a pit.

It can be done under the car but as sumo said... its one heavy bartard. If your going to do it yaself make a frame up for the box to sit on than have 2 trolly jacks underneath to lower it down.....Good Luck

keep us posted...

out.

lenno

[JimX]

How do you use the hoist under the car? Does something go underneath and through both sides? Maybe I could hire or borrow one or something.

[Lenno]

jimx.. i mean lift the car up on a hoist like at a workshop... but since i doubt you got a hoist in ya shed..go the trolly jacks with a custom made g/box support frame. This is what i did with my sierra g/box.... NEVER AGAIN !, i'm payin someone to do the r33

hope this helps, so that it can help us all, keep us posted..good luck

lenno

[2fardown]

This is how I would go about doing it:

*Buy 2 car ramps from super cheap for $25 each.

*Drive car on ramps

*Drain oil

*Get trolley jack with piece of timber on it, jacked up firmly under the gearbox

*Undo all nuts & bolts etc

*Slowly lower jack

The only problem I can see there is trying to strabilise the gearbox on the trolley jack so it doesn't fall off.

[JimX]

Lenno, ah Sorry for the misunderstanding! I was thinking you meant engine hoist, not car hoist. (man I'm stupid).

I think the first thing I'll need to do is sus out what parts I'll need. I might speak to a gearbox shop or something.

2fardown, I can't do your plan word for word, because my front bar is too low to drive onto ramps I'm just going to use my ramps to hold the car up after jacking it up (like axle stands but more stable).

[Lenno]

no problems jim, good idea sussin out parts first..... let the fingers do the walking

lenno

[hungry6]

hope u fellas don't break urself or box trying to it as some ppls suggested here. but that doesn't mean it can't be done, as i've done it and got good results with 2 crushed fingers and an swollen palm after it got pinned by the box. final analysis u can always make more money elsewhere but u can't grow new fingers or limb. and the box isn't easyto balance as it's rear end heavy biase.

[Jay95R33]

Jimx - dropping the box will be easy. I've done a 4wd box on a R32 GTS4-t and we had no problems. Sure the R33 one will be heavier, but you'll be right with two trolley jacks.

Putting the box back in takes time to get the splines to line up, just take your time and don't expect it to go back in the first, second, third, or even the fourth try !!

Took us about 40mins just to get the box to slide that extra 2 inches in to bolt it up (again, the splines weren't lining up). If you can, buy a lighnment tool...

Mine crunches into 2nd. So I'll be interested to see how you go.

I changed to VMX80 which helped a fair bit, but I've been tossing up to got to the redline stuff to try and get rid of it totally.

J

[2BNVS]

mine was crunching from 1st to 2nd but my mechanic changed the oil and since then its been all good....

cheers...ben.

[siksII]

Hey

just wanted to add that my friend got his Z32 gearbox(very similar or the same as ours) done(all synchros, his gearbox was gone in a big way...) plus a $1000 clutch put in for altogether $2000 as far as i can remember. So the gearbox labour and parts cost around 1k. Also consider that a z32 is probably more fidly to work on.

Give hills a ring...

[KamikazeR33]

when i took the gearbox outa mine... it was easy takin it out... exceopt for undoing 2 bolts which arent back in the damn thing atm

it was easy to slide it out... u just gotta twist it

putting it back in took us 15 goes and an hr to do

goodluck but id rather have someone else go through the pain and suffering

[JimX]

"id rather have someone else go through the pain and suffering"

I'm that way with many things on cars, including relatively simple (but messy) stuff like changing the transmission fluid. I think I'll wait until the crunching gets intolerable, and then check my bank account to see how much pain and suffering I'm willing to endure myself

[Kdawgboostin33]

Jimx,

Mate after speaking with SSS Automotive (I have the same problem) He recommended a place in Sydney that can redo your synchros for $1500.00 or what they are doing at the moment is rebuilding the RB25 gearbox with the RB26 Gears and synchros. So basically you will have a Taller first and a lot better ratios into 2nd 3rd and 4th, this was around $2,500.00 to do. Which is really not too bad. Especially when you smoke a GTR off the line