Background: As I previously posted my 56 series mid-close box 4 speed munched 3rd on the counter gear and I have since picked up an ultra close 56 series 4 speed. I did a rough estimate and I appear to be getting around 60 hours on the box before they shred 3rd on the counter hear. Despite the U/C being fresh I know it's only a matter of time (4-5 seasons) before it goes.
I need to do something long term

So my fellow racers what gearbox are using and what do you feel are the pluses?

A Steady stream of 56 series boxes, break replace repeat?

Toyota T50 with updated gear set?

Silvia AZ6 with custom bell housing?

Sierra Type 9?

My thought is find an auto bell housing and adapt an MX5 box as its ratios are nearly the same as the mid-close box.

As always any responses are greatly appreciated.

Tom

63 series?

Hi Tom,
Interesting that you should post this as I am having a few gearbox woes myself.
I had exactly the same issue with my ultra close 56A box and I elected to sell it following a rebuild after replacing 1st gear.
The box that I opted for is the dogsleg 5speed 60A box that has one of five kits that were commissioned to be made by an engineering shop over here ( Bethanies ) by Reg Cook who is the New Zealand equivalent of Pete Brock and quite a legend in Datsun circles with a rich and colorful history.
Now while the 56 box was really about 2nd/3rd/4th and 5th this box is really strong on the first 4 gears with a bit of a gap to 5th - still acceptable though.
With 3 and 4th gears straight cut it also has the added advantage of making some seriously cool noises!
While many would tell you the 60 series box is pretty strong regretfully mine has disgraced itself and taken a tooth off 4th gear on the cluster ( straight cut ) so I am faced with getting a whole new cluster made- perfect timing coming up to Xmas.
Given the age of the box and the fact that it no doubt would have had a heap of use ( and no doubt abuse ) in a rally car I really have to take this all on the chin but its definitely worth repairing as its a really nice c/r box.

Cheers
Dave

I'm running a T50 Celica

I also have a W50 celica thats abit beefier for the new project

Totally stock T50 has done many seasons in my rally car. A14 with some good mods but not massive power.

I collected 3 spare and never touched em

Stock ratios seem really good but we are using 4.9 diff ratio

Im interested as to why you would need close ratio? I think you mainly do track work (only use 3rd gear and above)? Or do you do motorkhanas as well?

I also had T50 behind A15ETT and never had a gearbox issue. I did a handfull of autocross (dirt surface) in that and general street work.

Its certainly been the robust option for me.

Early days in thr rally car we killed thr already abused 56 series 4 speed in it and replaced that with a 60 series 4 speed we had rebuilt. That seemed gteat but 2 events later the T50 5 speed come up so we put that in.

3T T50 toyota box. Currently with standard ratios, but intend on fitting a gear-set from PAR engineering [local in Sydney]. They other Dog or Synchro engagement. both straight cut. They also offer a pit gear conversion on 5th whereby top gear becomes 1:1 ratio [4th]. Ratios are to the customers requirements.

I used to run the 60A 5 speeds, standard ratios. Always wanted a close ratio 60A but they are expensive and rare. Thought about building one myself but would still cost quite a bit.
Have now got a Ford Rocket 4 speed box with a Quaife straight cut gear kit for when I put the car back together. Hopefully on the track again in 2016. Can't wait!

Hi Morgan,
Yes, the Ford 4 speed used to be a very popular conversion- 1600 Capri boxes I believe.
There was a chap in Nelson casting bell housings to convert to the Ford box but I haven't seen or heard of one for years.
Good conversion though, especially with the Quaife gear kit.
Cheers
Dave

The stock ratios are not such a problem with the A15 acceleration wise but they are not so great in the corners, invariably you get caught between gears. The 2800 rpm drop between 2nd and 3rd is not good.

One of our local autocrossers has offered to give me an A14 and 60 series 5 speed, so if it is possible to get a tighter 2nd 3rd for a 60 series then that would solve my dilemma. In the mid-close 4 speed I only use 2nd 3rd and 4th. With the current 4.38 rear gear I am seeing 7800 in 4th.

Here is the deal; while searching for spares for the 4 speeds I was offered up 5 speed 56 series U/C boxes but between the $1500 spent on the fresh U/C 4 speed and another $1300-1400 for a 5 speed it's near enough to $3000 for a gear set for a stronger box.

I've finally come to terms with the fact that there is no cheap way around a strong box with decent ratios. Guess I shouldn't have passed up on the Hall Hewland box a few years back....oops.

Tom

You could use an Aisin AZ6 from an MX-5, it has close gears and doesn't cost a fortune (less than $1000 on eBay). The 56-series is just too lightweight for anything other than an A12, even in TS Racing with the 1300 they had to be very careful with them!

Miata is closer than Close-ratio A12 transmission but not as close as the Ultra-close A12 gearbox!

MX5-99 3.760 2.269 1.645 1.257 1.000 0.843
F456c        2.862 1.908 1.350 1.000
F456uc       2.168 1.592 1.231 1.000