Gearbox Solutions

[08Elf]

Hey peeps,

My R32gts's gearbox (manual) is crunching changing gears sometimes.

I've been told the synchros and sliders need to be fixed.

I have had the oil replaced with synthetic stuff (Redline) still no good,

so I assume the gearbox will need to be fixed or for me to get a 2nd hand replacement.

I was browsing this site and the internet to look for solutions and from what I saw the following gearboxes go straight in without modification.

- VL/R31

- R32 (RB30det)

- R33 (RB25det)

Is this true?

Being a turbo charged car will the VL/R31 box handle about 200rwkw?

I've been quoted $2000 to get it rebuilt, this is ion Canberra where prices are normally inflated.........is this expensive? How do other states compare?

I might go to either Sydney or Melbourne if the price differential is big.

[Sydneykid]

Hey peeps,

My R32gts's gearbox (manual) is crunching changing gears sometimes.

I've been told the synchros and sliders need to be fixed.

I have had the oil replaced with synthetic stuff (Redline) still no good,

so I assume the gearbox will need to be fixed or for me to get a 2nd hand replacement.

I was browsing this site and the internet to look for solutions and from what I saw the following gearboxes go straight in without modification.

- VL/R31

- R32 (RB30det)

- R33 (RB25det)

Is this true?

Being a turbo charged car will the VL/R31 box handle about 200rwkw?

I've been quoted $2000 to get it rebuilt, this is ion Canberra where prices are normally inflated.........is this expensive?  How do other states compare?

I might go to either Sydney or Melbourne if the price differential is big.

An RB20 DET gearbox is pretty much the same as a VLT gearbox, they cost ~$500 to service in Sydney. If you go to a RB25DET gearbox there are a number of things you need to change as well that inflate the costs (tailshaft, speedo drive etc)

[08Elf]

Is that $500 plus whatever parts are required?

or a rough total?

I was told by 1 place that it would be $450. I thought this was a really good price then he told me that was for them just to open it and have a look, that parts would be extra.

[Sydneykid]

Is that $500 plus whatever parts are required?

or a rough total?

I was told by 1 place that it would be $450.  I thought this was a really good price then he told me that was for them just to open it and have a look, that parts would be extra.

Obviously if the gearbox needs a new mainshaft, selector hubs or output shaft then the price is higher. But if it is genuinely synchros, bearings and seals then $500 is a working average. You really can't tell until you open it up and do a detailed inspection.

[08Elf]

Not being a mechanic I don't honestly know if it is synchros, but when the guy drove my car he said it was.

[The Mafia]

yeah mine is like this too, its bad when the car is cold, and not bad when its hot.

I find the worst are

1st > 2nd Cold

4th > 5th hot and under load

3rd > 4th Hot and under load

[blind_elk]

You have fluid in the master cylinder?

It could be a worn out clutch. If you remove the gearbox for repairs, make sure you replace the clutch, because the major cost here is labour.

[kwazza11]

from my experiances VLT gearboxes are a fair bit bulkier than the rb20 boxes, just the physical size of the housings alone is different and from comparing the rb20 and rb30et gearbox main bearings shows the rb30et ones could definately handle more hp than the rb20det one.

i put new bearings and synchros in my last RB20 box after it started rattling to shit after a few full boost 5th gear runs. i managed to totally destroy the main centre bearings, one of them only had 4 (!!) balls and half a bearing cage left between the races :chairshot

hunted around for the bearing kits and found the rb30e (r31 and vl non turbo) kits to be the same as the rb20det. got the synchro's genuine as the rb20 box has double synchros for 2nd and 3rd.

doit yaself man! best way to learn

[R31 POWER]

Was it fine after that kwazza11? and did it last? like no noises

[Cubes]

What price did it set you back for the bearings and syncro's?

[kwazza11]

yea its lasted fine.. i sold the car about 2 months after i rebuilt it (that was 6 months ago) and spoke to the guy a week ago who bought it and he recons he thrashes the guts out of it and its still perfect, and i wasnt kind to it in the last couple months either.

but yea i refrained from high speed full throttle fun after that and used some good quality oil.

cant remember the exact price but off the top of my head it wasnt anything over $200 for the bearing kit from CBC and 1st, 2nd and 3rd synchros were about $80 all up from nissan (trade price on both, cause i deal with them alot at work)

[Cubes]

How is the gearbox setup?

I've rebuilt 4speed single rail box's before that had obviously a front and rear main bearing.. Needle rollers within the main gears and hundreds of needle rollers on a lay shaft.

I sat there for soo long sticking on all of the needle rollers for the lay shaft.

[kwazza11]

heheh

well the rb20det is a fair bit easier, all the needle bearings for the gears are captive so all you need to do is press off the old races and press the new ones on then slide it all together, theres a few specs you've got to follow like selecting snap rings to alter end floats but just grab yourself a workshop manual (i used an aussie r31 one) and its got a step by step walkthrough of putting it together. from memory theres differences like slightly different selector forks and dual synchros on the rb20 box but apart from that thier pretty similar.

[R31 POWER]

I got another RB20det box and will be putting new bearing and synchros thru it very soon.

[Cubes]

Take Pics!!!

For the D.I.Y Section.

I will then rebuild my box write up a guide (If you dont want to) and see how long it lasts with the 3ltr.

[R31 POWER]

I'll see what I can do Joel.

[discopotato03]

Silly me went to a lot of trouble and expense to put the guts of an R32GTST box in the casings of an FJ20 box a few years back . There have been so many variations in those 71 series boxes its not funny . The R32 box came from Triple S , I wanted all the wide gears and large syncro hubs plus the larger countershaft front bearing . I had thought all RB71 boxes were the same , have never seen twin cone syncros in them . I think the R33 25T boxes are the same series as VLT and Z32 VG30 . The VLT has wider spaced ratios than R33/Z32 to suit its high final drive (3.45 ?) and lower reving nature . I noticed once in a 4WD/commercial wrecker some gearboxes that looked similar to 33/25T possibly from VG30 Navara , these would probably be wide ratio but at least pretty strong . With the 71 series boxes to get closer ratios we used to change the first motion shaft (input gear) and the front cluster gear , not sure but may also be the case with the large series box . If your handy with the spaniards and get bits at the right prices maybe a cheaper 25T gearbox can be bitzered together .

Cheers A .

[Alf]

Sooner or later I'm going to be faced with choosing a manual :Bang:

I dont think a RB30 or a 25 box will withstand a 600hp+ RB30DET with something I want to be reliable and strong.

If I'm going to be paying decents amount of $ i would go for something a big stronger than a factory RB box. I have been looking at TKO 5spds, they cost 5k plus. I have also been looking at the T56's used in the gen 3 comies but i'm concerned about the gear ratios in them, they are ment for a 5.7L and maybe too tall for what I want.

I have seen some decent priced supra 6 spds but i've never seen one an RB.

I wouldn't mind a close ratio 6 speed to make it more "fun" to drive and still be able to cruise in 6th with reasonable fuel economy. :headspin:

[Alf]

T56 ratios as in a gen 3

1st 2.66:1

2nd 1.78:1

3rd 1.30:1

4th 1:1

5th 0.74:1

6th 0.50:1

Would using a T56 on a RB30DET with 4.11 diff gears be any good?.

[RB20LagWagon]

While not knowing the exact rb20 or rb25 gear ratios (I think the first gear is 3.5xx:1 and very similar between the two boxes) the t56 is built for low revving big torque v8s so i think it would be over geared something cronic, even with 4.11s.

Also not to argue with SK but the vl turbo gearbox is more similar to the rb25det box then the rb20det box. They even share designations as the MX7 and MX7a. The non turbo vl gearboxs r31 gearboxes and r32 5 speeds are all very similar. VL turbo gearboxes have been known to hold 500 rwhp. However the gearchanges in the vl turbo box are pretty awful, where the r33 box is nice and the r34 is very very very very nice.

Doh, or what discopotato just said.