Final Drive

Final drive blog

Day 1:

Today we started final drives; the final drive I worked on was a banjo type differential non-limited slip using hypoid gears from a Mazda 808

The first thing I did was check for the final drive identification; it said it was from a Mazda 808

Then I checked for markings on the differential housing caps there where yellow marks identifying the left hand side cap.

Next I checked for identification marks for the pinion and crown wheel, they were marked with a white line

Now I start to dismantle the final drive, first I remove the differential case assembly

As the crown wheel position on the case is already marked I don’t have to do this

Next I unbolt and remove the crown wheel bolts, then I remove the pinion nut

Now I start my inspection of the components, I am looking for chips, cracks, bur and gully’s in the teeth as well as any pitting

The crown wheel teeth are in good order there is no visible sign of damage

There is minor damage to the crown wheel bolts as the threads on them have been squared off slightly

The condition of the threads in the case is good there is no visible sign of damage to them

Next I remove the roll pin retaining the spider gears and cross shaft and remove the cross shaft

Next I remove the spider gears and side gears

Then the gear thrusts are removed and I can carry out the inspection of the following parts:

On these parts I am looking for cracks, chips, pits and bur

The side gears are in moderate condition and have slight chipping on the teeth but can be returned to service

The side gear thrusts are in good condition and show no visible sign of damage and can be returned to service

The spider gears are in good condition, there is no visible sign of damage to them and they can be returned to service

The spider gear thrusts are in good condition, there is no visible sign of damage to them and they can be returned to service

The cross shaft shows no sign of visible damage and can be returned to service

The roll pin shows a slight squaring of the roll pin but is fit to be returned to service

The case shows slight scratches inside and out, also shows slight cracks inside it

The final drive ratio is measured with the equation “driven” divided by “driver” gears for this final drive is 37 divided by 9 giving us a 4.11:1 ratio

Pits in the gears will cause excessive backlash

Cracks will cause structural integrity in the gears to fail

Chips will cause the gear teeth to collapse

Bur will cause a raised edge on a machined metal causing hardening

This concludes day 1

Day 2:

Today I started by measuring the backlash of the side gears

The specification for this is between 0.1-0.2mm

Gear 1 measured at 0.5mm this is a failed result

Gear 2 measured 0.2mm which is a pass result

The incorrect clearance could be recified by putting a thrust washer between the body and the no.1 gear

Next I proceed to refit the crown wheel to the case and align the position marks

Then I refit the crown wheel bolts (the correct sequence is to tighten opposite bolts)

The specification for the bolts is 71ft-lb (of note for this exercise we use only half the specification)

In this differential a collapsible is used.

Next I inspect the condition of the pinion gear, for this I am looking for pits, bur, chips and cracks

The pinion teeth are in ok condition, there is no bur, chips or cracks but there is minor pits

The pinion splines are in good condition, there are no pits, bur, chips, or cracks

The pinion thread is in good condition, there is no cross threads, chips or cracks

The spacer’s and shims are in good condition, there are no chips or cracks in them

The bearings are in good condition, they are roller bearings there are no pits, chips or cracks and they are spinning freely.

This concludes day 2.

Day 3:

Today I started by checking the crownwheel run out this is done using a D.T.I this measures the side to side movement respectively known as run out.

I did bot a radial run out and a lateral run out check

For this test the manufacturers specification is between 0mm – 0.1mm

The radial check recorded 0.03mm which is within the specification

The lateral check recorded 0.01mm which is within the specification

Next I start to reassemble the differential, I start by lightly oiling the bearings and threaded surfaces

Then I reassemble the pinion with the spacer and oil seal and tighten the nut,

Next I have to put pre-load on the pinion this is done using a loader leaver.

The manufacturers specification for this is 7.8-11.3 I-lb(inch-pounds)

I then check the position of the nut, there is a difference in the position of the nut because there is a new preload on it.

The previous pre-load was 8 I-lb

Next I refit the crown wheel and differential case into the carrier, followed by refitting the bearing caps and adjuster nuts

I then set the carrier bearing pre-load using the D.T.I.

After that I checked the backlash of the crown wheel for this the D.T.I has to be kept at right angles to the crown wheel teeth and the crown wheel rotated gently taking measurements in four different places.

The specification for this test is 0.13mm-0.18mm

Reading 1 was 0.13mm, this is within specification and a pass result

Reading 2 was 0.14mm, this is within specification and a pass result

Reading 3 was 0.13mm, this is within specification and a pass result

Reading 4 was 0.14mm, this is within specification and a pass result

Next I check the tooth contact marking, this is done using bearing blue or red lead, we used red lead and lightly coat 3or 4 teeth on the crown wheel then under load we rotate the crown wheel in both directions, one way then the other and then inspect the markings

After inspection of this differential I determined that the side bearings need to be adjusted and a thinner pinion position shim is required as it has to much toe in it, the further adjustment needed is to bring the pinion out of mesh and the crown wheel inwards.

The final thing I do for final drive is to check that the bolts are all set to the torque specification settings,

Of note is that there is no lock bolts and tab to carrier bolts as they are missing on this unit

This concludes final drive.

Clutch, C.V and driveshaft

Day 1: Today we first did a inspection of a clutch assembly

This clutch is a cable clutch from a toyota 3k motor mounted to the motor for this purpose
First we check that the transmission fluid has been drained, which it has.
We then remove the drive shafts and gear linkage.
Next we disconnect the clutch operating mechanism
Then we removed the gearbox mounting's while supporting the gearbox itself
We then proceeded to remove the bell housing bolts
We marked the clutch cover to the flywheel for when we re-assemble it
Finally we evenly remove the clutch cover bolts to prevent distortion.
With that all removed we can now carry out our inspection

Flywheel has no damage and is show's no signs of wear or over heating and is suitable for further use
Pressure plate has no damage, but shows signs of wear, no signs of overheating but will need to be replaced
Clutch plate has no damage, but has excessive wear on it, no signs of over heating, but will need to be replaced.
Release bearing shows no damage, but has wear on it, no signs of over heating , will need to be replaced
Release fork shows no damage and it shows no signs of wear or over heating is suitable for further use
Release linkage shows no damage and it shows no signs of wear or over heating is suitable for further use
Sprigot bearing shows no damage and it shows no signs of wear or over heating is suitable for further use
Clutch housing shows no damage and it shows no signs of wear or over heating is suitable for further use
Sprigot shaft shows no damage and it shows no signs of wear or over heating is suitable for further use
Also there are no visible oil leaks on the motor

Our inspection has concluded that the release bearing's need replacing,
The pressure plate need's replacing,
And also the clutch plate needs to be replaced

(above: pressure plate & clutch plate)

Next we proceeded to do a run-out test on the flywheel using a Dial Test Indicator(DTI) the specification for the flywheel run-out is 0-0.15mm, our test returned a result of 0.05mm of run-out

We now clean all the clutch and flywheel surfaces to ensure there are no signs of oil, 

we also identify the correct flywheel side of the clutch plate by identifying the raised side of it goes to the flywheel.

Next we measure the size of the sprigot shaft and find the dummy shaft to align the clutch

We then assemble the clutch assembly on the dummy shaft

Next we locate the clutch cover marking's

Then we fit all the pressure plate bolts in the correct order and tighten in the correct order

Now we torque them to the manufacture's specifications

Next we check that the alignment of the clutch is correct 

We refit the the transmission and align the sprigot shaft into the clutch assembly

Next we install the mounting bolts supporting the gearbox until this is finished

The clutch linkage on this gearbox is adjusted with a setup on the firewall

We proceed to check all clutch linkage for correct operation.

We ensure that the clutch mechanism is working full and freely

Next we started work on a constant velocity joint (C.V Joint)

(c.v joint, ref: http://www.2carpros.com/images/articles/drivetrain/cv_axle/front_cv_axle.jpg)

First we check the c.v joint for roughness, play or binding

Our c.v joint operated smoothly, our c.v joint didn't have anyplay that exceeded the manufactures specifications.

Excessive play in the c.v joint can cause damage to the joint and can result in the c.v joint starting to click under steering stress.

We checked  all rubber seal's for damage there wasn't any on them

We remove the retaining clips and slide the boot out of the way

Next we place match marks on the driveshaft for when we re-assemble it

Then we remove the joint from the shaft, removing all snap rings and circlips

We clean the joint next so we can inspect it properly 

For our inspection we check: 

The outer race, inner race, ball cage, balls & roller's, spline's, threads, circlips, circlip grooves. we check for crack's, chip's, damaged threads, pits, etc

The outer race has no damage to it and can be returned to service

The inner race has no damage to it and can be returned to service

The ball cage has no damage to it and can be returned to service

The ball's and roller's have minor marks to it but can be returned to service

The splines have no damage to it and can be returned to service

The threads have no damage to it and can be returned to service

The cir clips have no damage to it and can be returned to service

the cir clip groove's have no damage to it and can be returned to service

The tripod should be replaced in this c.v joint should be replaced as it has dents and marks on the rollers

(above: c.v tripod, ref: http://www.manufacturer.com/cimages/buyLeads/www.alibaba.com/1027/e/KIA_PRAID_C_V_JOINT_AND_TRIPOD.jpg)

After carrying out our inspection we re-assemble the c.v joint to the correct specifications given

Day 2:

Today we started on our driveshaft and cross type universal joint inspection, for this we required the use of a big hammer, big punch, wooden blocks, a dial test indicator, screw drivers, spanner’s, punch’s and plier’s

The first thing we check is the driveline phasing, phasing is how the joints are mounted to the driveshaft on our driveline the phasing can’t be altered

The phasing of our driveline is correct as it can’t be altered so no correction is required

(Driveline in-phase)

The method we us to check the driveshaft for imbalance is to put it on a table in “V” blocks and measure it using a D.T.I at 3 different points, To correct a drive shaft imbalance you would put weights on the opposite of the high side.

(Driveline D.T.I test)

We used a D.T.I to test for driveshaft imbalance, for this test the manufacturer’s specs are 0mm-0.6mm the measurement’s we got where:

Front: 0.49mm

Middle: 0.44mm

Rear: 0.32mm

We check the driveshaft universal joint, this is done by checking for axel play and roughness in the joint.

Our universal joint operated smoothly, there was no roughness in its operation

There was also no axial play in the universal joint

This brings us to the conclusion that the universal joints are in good condition and can be returned to service,

Next we start to remove the universal joints, first we make marks for when we reassemble the driveshaft, we then then removed all the circlips and snap rings from the universal joints.

This concluded day 2

Day 3:

Today we removed the universal joints, then cleaned them for a thorough  inspection,

We check for cracks, chips, damaged seal’s ,

(Cross joint)

The cross join surface shows no signs of damage to it and can be returned to service

The caps have no visible damage to them on the outside or inside, we checked this with a torch on the inside and can be returned to service

The rollers have no signs of damage about them and can be returned to service

The seal’s have no cracks chips  or splits in them thus they are in good condition

The yoke surface’s show no signs of chipping or cracking so they can be returned to service

We proceeded to reassemble the drive line our report has concluded that there are no drive shaft problem's and this drive shaft is able to be returned to service

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