S53 Gearbox stripdown & findings

S53 Gearbox stripdown
The optimist voice in my head said "open the spare S53 and see if it's an easy fix"
The other rational voice said "forget it - that kid fukd it good!"
The box was good apart from the fact it refused to stay in 1st or 2nd gear, those 2 gears
share an actuator so I was being optimistic.

Usually it's 2nd, then 1st that goes due to the amount of torque those gears have to transmit.

Removing the outer cover I could aready see the box had been re-furbed before
How do you fuk a box TWICE in less than 140 000km???

Outer casings & 5th gear removed



The gears and linkages complete minus 5th gear



The gears with linkages removed, note reverse gear idler seperate on it's own shaft



The gears from the other side, reverse idler gear removed to show the shafts
Bottom small gear is 1st, straight cut gear is reverse (that's why it whines in reverse, race boxes are also straight cut),
then 2nd, 3rd, 4th above. 5th sits outside the main casing on those splines at the top and easily changed without opening the box.
(6 speed conversions lenghten those shafts and add another gear outside the 5th gear, using the 5th gear selector to work in 2 directions)



The gear linkages, note they are covered in nylon for better wear, noise etc. C-Series boxes do not have
the nylon covers, there are NO interchangable parts in the C-Series



The gears and diff removed, the diff is matched to the secondary shaft - ie. you cannot change the diff ratio
without changing the secondary shaft as well. The gears are pressed onto the shaft apart from 1st, R, 2nd which
are machined as part of the primary shaft. Changing diffs/ratios/shafts is not as simple as you would think!



The inner casing (bellhousing) with it's large roller bearings, can be swapped with MR2 or FE type bellhousing



Unfortunately all the syncros (incl 5th & reverse) were totally fukd due to hooligan antics, so some parts have gone into
the spares collection, the rest are in the bin.

BE WARNED - Short shifters & crash changes!
These gearboxes use brass rings to "brake"/slow the spinning gears before the teeth can mesh (similar idea to your handbrake shoes)
If the gears don't have enough time to slow down due to short shifters or crash changing, thin oil, oil additives etc
The syncro teeth are ground away by the motor, resulting in a box which struggles to select gears, won't stay in gear etc,
and the gears then look like this...



I also recommed using 80W/90 Gear oil, ATF is designed for Auto boxes and does not protect your gears and bearings as well as gear oil,
esp if you are prone to ramming it into gear. (Auto boxes use hydralics or magnets to keep it in gear and have an oil cooler to keep temps down!)
ATF is great for race gearboxes which are overhauled regulary, not in a 22yr old worn box.

My box turned out to be a std JDM item, gear ratio's are as follows:
1st - 14/46 = 3,286
2nd - 24/49 = 2,041
3rd - 31/41 = 1,323
4th - 35/36 = 1,028
5th - 39/32 = 0.820
Diff - 17/71 = 4,176

Which is actually very disappionting, the JDM car is set for very fast acceleration with very little top speed ie:
(a 1500cc Alfasud has longer gearing and higher top end!!!), it will be difficult to get more than 210km/h out of these ratios.
Great for track/rally use but totally useless for economy in highway use.

I'm now looking for a 5th gear set 0.731 or lower ratio to suit these boxes? Anybody got a busted box?
Anybody got a busted box in N.Z with a 3.9 or 3.6 diff?
What seals are interchangable between the boxes?


Easy filling Tip
I found an easier way to fill these boxes. Remove the filler plug and the reverse switch on the top.
Put a small funnel into the switch hole and fill till oil runs from the filler hole - easy!

 

I wouldn't go so far as to say "soft", they are 20+ yrs old and
starting to show their age.

I stripped a Corolla "C" series thinking I could use parts from it,
these boxes are way beefier and stronger than the C series.

I bought 2 cars, one had been thrashed by a teenager and the entire
drivetrain was knackered, (photo of the blue bearings on my page etc)
Gears would not stay in and seals leaking, clutch looked like black candy floss

The other (TEMS) had been driven by a lady for 15yrs, apart from the head
gasket which had rusted away completely, the drivetrain is perfect and
feels like new

Thrash anything long enough and it will go soft

 

Only way I know of is to mate the "S" bellhousing to a BZR box

It's possible but not easy, this one was built for a MR2 and the site is on the wall



I have a spare box & waiting for a 6 spd BZR to come available, all in good time

 

No, not necessesarily

Gearing is the holy grail of motorsport and the big secret behind many quick cars,
races are won/lost on gearing choices

The more torque a motor has, the less gears it needs

1) Dragsters & drag bikes only have 2 gears, Sprintcars & Midgets have 1 gear & still wheelie out of corners
2) You actually waste time changing gears and lose traction as well
3) Race cars have long lower gears getting shorter as they go up,
gives them more torque in the lower gears and enables the revs to stay up in the higher gears
4) The 6 speed box is shorter than our boxes, it comes from a 1600-1800cc motor and to go faster
you need to change to a lower diff ratio
6) 6 speed or more boxes are really only effective in cars/bikes with a narrow powerband at high revs and very little torque.
7) You will be changing gears far more in daily driving - Hello tennis elbow!

 

Them plus the sleeves

Id replace all the gear bearings and bolts/nuts as well

 

I will - oneday
It won't be cheap, add up the price of the bearings, syncros, sleeves and those spacers will need to re-sized as well

 

Yes the S52/53 gears are interchangable, I've been looking for a 0.7 for quite a while now

Lol Rick, filling thru the upper drain hole suxx major, on the auto's I just use a small funnel with a thin tube down the dipstick tube

 

Hard, the 1st gear synchro is part of the 1/R/2 synchro and the last part you can get to.
1st gear is only used when stationary? Try holding the clutch down longer before engaging
(gives the gear more time to slow down, same goes for crunchy reverse)

Cheaper to source a later S54 as to find synchro's and bearings will set you back $500+, plus replace the damaged parts + labour + tools.

I'm finding the main reason for boxes failing is loose bearings, even on the "E" boxes things start breaking when there's too much play.
Synchro rings and synchros can't engage or stay engaged when the gear itself isn't stable


Gears on worn bearings tend to spin a lot longer with less friction to slow them down, once the rollers come loose and break up the ultra hard bits go everywhere and destroy everything.
Expect to see a lot of S & E box failures in the next few years - I was recently shown an S54 which broke the teeth off a crownwheel & gears due to bits flying around.


If you want, you can be a guinea pig for us (as the box is going anyway)
Pour 200ml of engine flush into the box (Through the reverse or adjuster holes)
Drive it for a day and then drain the oil overnight (needs to drain everything)
Then fill with LSD oil and see how it feels

The theory is that the synchro cones are polished over time and coated with anti-friction
materials.

(I'm going to try sandblasting these)

Hopefully the engine flush will dissolve the coating and help the synchros bite better.
The LSD oil is supposed to have friction properties which will also help synchro action

 

Well, it can't do any harm
The LSD oil is supposed to help LSD's and synchro's, the engine flush I added to dissolve any buildup in the gearbox.