Manual transmission

Day 1: this week we have moved on to manual transmission from auto transmission, today Myself and James have started by disassembling a manual gearbox from a ae92 toyota Levin(I know for a fact this gear box is from a Levin as it is out of a 4age engine and that ae92 is the Levin model number for the 1989 levin and I have owned one in the past)

This is the complete gear box at the start

We have taken off the end cap exposing the fifth gear

From here we could remove other components such as the syncro’s shifter forks and the gear’s them selves.

We had to use a gear puller in order to remove the fifth gear

Also we have removed the gear selector assembly

We then proceeded to remove the transaxel case exposing the rest of the gears.

Below we have the input and output shafts

This is the clutch housing with everything removed

And this part is the crown wheel(above)

Day 2: Today we begin our inspection and take our measurement for this gearbox including the gear ratio's

Our gearbox is a 4age 5 spd manual,

it selected all gear's on the initial testing and the exterior looks to be in good order,

Bearings

For this we check for freedom of movement, taper on the bearing and how loose or tight it is

Input shaft (front) used a roller bearing and was in good condition

Input shaft (rear) used a roller bearing and was in good condition

Output shaft (front) used a roller bearing and was in good condition

Output shaft (rear) used a roller bearing and was in good condition

Final drive bearing (right) used a roller bearing and was in good condition

Final drive bearing (left) used a roller bearing and was in good condition

First gear bearing used a roller bearing and was in good condition

Second gear bearing used a needle roller bearing and was in good condition

Third gear bearing used a needle roller bearing and was in good condition

Fourth gear bearing used a needle roller bearing and was in good condition

Fifth gear bearing used a needle roller bearing and was in good condition

Reverse gear bearing used a bush and was in good condition

Gears


For this we check the condition of the teeth, if the hardened face is worn, if there are any chipped teeth, if there is any bur on the teeth and the condition of the synchro dog teeth.


First gear driver: 12 teeth, side clearance is n/a as it is fixed in position

First gear driven: 38 teeth, side clearance is 0.229mm, slight amount of bur on teeth
Second gear driver: 21 teeth, side clearance is n/a as it is fixed in position,slight amount of bur on teeth
Second gear driven: 40 teeth, side clearance is 0.229mm, slight amount of bur on teeth
Third gear driver: 29 teeth, side clearance is 0.203mm, slight amount of bur on teeth
Third gear driven: 38 teeth, side clearance is n/a as it is fixed in position, small fraction amount of bur on teeth
Fourth gear driver: 33 teeth, side clearance is 0.330mm, fraction of bur on teeth
Fourth gear driven: 32 teeth, side clearance is n/a as it is fixed in position, slight amount of bur on teeth
Fifth gear driver: 38 teeth, side clearance is 0.229mm, teeth are in good condition
Fifth gear driven: 30 teeth, side clearance is n/a as it is fixed in position, teeth are in good condition
Reverse gear driver: 12 teeth, side clearance is n/a as it is fixed in position teeth are in good condition
Reverse gear idler: 29 teeth, side clearance is n/a, teeth in good condition
Reverse gear driven: 39 teeth, side clearance is n/a, teeth in good condition
Final drive gear driver: 17 teeth, teeth are in good condition
Final drive gear driven: 69 teeth, teeth are in good condition
Speedometer gear driver: 34 teeth, teeth are in good condition
Speedometer gear driven: 31 teeth, teeth are in good condition

Synchro system


For this we check if there is any wear to the baulk ring, the side clearance and any wear to the teeth.


Baulk ring (first): in good condition, clearance is 0.900mm
Baulk ring (second): in good condition, clearance is 0.559mm
Baulk ring (third): in good condition, clearance is 0.799mm
Baulk ring (fourth): in good condition, clearance is 0.711mm
Baulk ring (fifth): in good condition, clearance is 0.660mm
Shift plates are in good condition
Wire springs are in good condition
Synchro hubs are in good condition
Shift sleeves are all in good condition


Selector mechanism


For this we check to see if there is any damage/wear to the detent ball's and springs, if there is any damage/ wear to the interlock balls and if there is any damage to the selector fork's and shafts.


Detent system: is a ball and spring type(captured ball and spring) and is in good condition
Interlock: is a dual ball bearing type and is in good condition
Selector forks are in good condition
Selector shafts are in good condition


Shafts


For this we visually inspect to see if there is any damage to the input, output, reverse idler and selector shafts, then measure the length of them.


Input shaft measure's 25mm(24.9mm) input shaft is in good condition
Output shaft measure's 33mm, output shaft is in good condition
Reverse idler shaft measure's 18mm(17,97mm) reverse idler shaft is in good condition
Selector shaft's measure 14.98mm(1st shaft), 14.97mm(2nd shaft), 14.97mm(3rd shaft) all shafts are in good condition

Here we check to see if there is any damage such as cracks, cross threaded bolts etc to the parts that follow.


Circlips are all in good condition
Splines are in good condition
The housing and cover's are all in good condition
Breather is in good condition
Seals are in good condition
Threaded holes and bolts are in good condition


Gear ratio's
The gear ratio's are worked out using the following formula: 
The formula for this is the driven gear teeth divided by the driver gear teeth from the previous information gathered.


First gear: 38/12= 3.167:1
Second gear: 40/21= 1.915:1
Third gear: 38/29= 1.310:1
Fourth gear: 32/33= 0.970:1
Fifth gear: 30/38= 0.790:1
Reverse gear: 39/12= 3.250:1
Final drive: 67/17= 4.060:1


Day 3: On day three after having obtained all the required information and determining that this gear box is fit to return to service we then proceeded to re-assemble the 4age gear box, we came across a minor complication of the shafts not lining up but quickly rectified it, and successfully re-assembled the gear box to a working order