Rupunzell
Bernice Loui
This 1979 5 speed transaxle arrived from a friend's race car with the innards needing attention.
Part one shows how to take one of these apart.
Transaxle on the bench ready to be worked on.
Un do the two M6x25mm long bolts using a 10mm wrench holding the input shaft sleeve which the clutch release bearing slides on, remove this sleeve.
Using a 13mm socket, remove the three M8x50mm long bolts inside the bell housing. Use a 13mm wrench to remove the clutch release bearing fork screw from the clutch release arm & shaft and pull it out the top.
A slide hammer with an adapter to fit on to the M8 x 1.25 threaded holes on the drive flanges is required to remove these drive flanges. There is a snap ring groove at the end of the drive flange splines that will dis-engage when pulled. Some pry on these drive flanges to remove them, there is risk of damage if this method is done. Easiest and quickest way is to apply the correct tool.
Removing the other drive flange ( got John with the blue gloves to do this part of the take apart).
Remove the four M8x30mm long cap screws using a 13mm wrench that retains the diff carrier bearing cover. Make sure to remove the precision ground spacer which looks like a thin washer and keep it in a safe-known place.
Using a 13mm hex drive implement of your choice, remove the two M8x100 mm long cap screws and two M8x80mm long cap screws and two M6 nut/bolt that secures the 5th gear cover and remove that cover to reveal this;
After years of dealing with these gear boxes, this input shaft holder was made from an old clutch disc center and 1" nut which fits a 1-1/2" hex drive tool. This is applied to the input shaft to stop it from moving.
The two M20x1.5mm nuts are removed using a 30mm socket & 3/4" drive impact wrench. No need to un-stake the nuts as they spin off with that much impact torque. Not shown is the removed 5th gear shift fork and engagement of 5th gear to allow removal of this nut from the countershaft/final drive pinion gear shaft.
Nuts removed. These nuts are Knackared. If the gear box has been worked on previously, the nuts are often re-used against the Fiat service manual's recommendations. The torn and beaten staked areas are a potential failure that could happen, so these are replaced when it this gear box goes back together.
Lift off the 5th gear assembly including the sleeve bearings and all, then remove the plate between the 5th gear cover and case.
*Note the key drive 5th gear, this is common on 1979 and early 1980 gear boxes, some time later, Fiat changed to a spline drive 5th gear they are not interchangeable in any way and there are other various internal differences depending on the specific gear box.
Remove the shift dent cover carefully as there are three springs and three steel dent balls. The 5th & Reverse spring is shorter than the other two and made of thicker wire. Remove the steel detent balls using a magnet, place all these parts in a safe-secure location.
Under the plate are the two rear bearings with snap rings. Either remove the snap rings or remove the bearing without damaging them. There are two slots under each snap ring to aid removal. One of these bearings is split if it is original or replaced with an original. Later gear boxes do not have the split bearing.
Once the two snap rings have been removed, use a 13mm hex socket and remove all the M8x50mm cap screws holding the case together. Once all the M8's have been removed, split and lift off the case top.
Remove the reverse idler gear shaft by undoing the M6x20mm cap screw and triangle lock tab.. Early gear boxes have a 16mm shaft, later ones have an 18mm shaft and matching gear.
Using a 10mm hex drive implement, remove the shift translator assembly and reverse lock out unit underneath.
Once the shift translator unit is removed, the entire gear set, shift forks and shift rods can be lifted out of the lower case. Once the gear set assemblies have been removed, lift out the diff assembly.
What remains in the lower case are two large shift lock out beans and one small one on the end of the middle shift fork shaft or 3rd/4th shaft. DO NOT LOOSE THIS SMALL BEAN or there will be much grief later.
The small bean.
The three beans.
Using a 10mm socket in a universal, remove the shift translator coupler to shift shaft screw. This one is special.
Remove the shift shaft from the lower case.
Done for now.
Bernice
Part one shows how to take one of these apart.
Transaxle on the bench ready to be worked on.
Un do the two M6x25mm long bolts using a 10mm wrench holding the input shaft sleeve which the clutch release bearing slides on, remove this sleeve.
Using a 13mm socket, remove the three M8x50mm long bolts inside the bell housing. Use a 13mm wrench to remove the clutch release bearing fork screw from the clutch release arm & shaft and pull it out the top.
A slide hammer with an adapter to fit on to the M8 x 1.25 threaded holes on the drive flanges is required to remove these drive flanges. There is a snap ring groove at the end of the drive flange splines that will dis-engage when pulled. Some pry on these drive flanges to remove them, there is risk of damage if this method is done. Easiest and quickest way is to apply the correct tool.
Removing the other drive flange ( got John with the blue gloves to do this part of the take apart).
Remove the four M8x30mm long cap screws using a 13mm wrench that retains the diff carrier bearing cover. Make sure to remove the precision ground spacer which looks like a thin washer and keep it in a safe-known place.
Using a 13mm hex drive implement of your choice, remove the two M8x100 mm long cap screws and two M8x80mm long cap screws and two M6 nut/bolt that secures the 5th gear cover and remove that cover to reveal this;
After years of dealing with these gear boxes, this input shaft holder was made from an old clutch disc center and 1" nut which fits a 1-1/2" hex drive tool. This is applied to the input shaft to stop it from moving.
The two M20x1.5mm nuts are removed using a 30mm socket & 3/4" drive impact wrench. No need to un-stake the nuts as they spin off with that much impact torque. Not shown is the removed 5th gear shift fork and engagement of 5th gear to allow removal of this nut from the countershaft/final drive pinion gear shaft.
Nuts removed. These nuts are Knackared. If the gear box has been worked on previously, the nuts are often re-used against the Fiat service manual's recommendations. The torn and beaten staked areas are a potential failure that could happen, so these are replaced when it this gear box goes back together.
Lift off the 5th gear assembly including the sleeve bearings and all, then remove the plate between the 5th gear cover and case.
*Note the key drive 5th gear, this is common on 1979 and early 1980 gear boxes, some time later, Fiat changed to a spline drive 5th gear they are not interchangeable in any way and there are other various internal differences depending on the specific gear box.
Remove the shift dent cover carefully as there are three springs and three steel dent balls. The 5th & Reverse spring is shorter than the other two and made of thicker wire. Remove the steel detent balls using a magnet, place all these parts in a safe-secure location.
Under the plate are the two rear bearings with snap rings. Either remove the snap rings or remove the bearing without damaging them. There are two slots under each snap ring to aid removal. One of these bearings is split if it is original or replaced with an original. Later gear boxes do not have the split bearing.
Once the two snap rings have been removed, use a 13mm hex socket and remove all the M8x50mm cap screws holding the case together. Once all the M8's have been removed, split and lift off the case top.
Remove the reverse idler gear shaft by undoing the M6x20mm cap screw and triangle lock tab.. Early gear boxes have a 16mm shaft, later ones have an 18mm shaft and matching gear.
Using a 10mm hex drive implement, remove the shift translator assembly and reverse lock out unit underneath.
Once the shift translator unit is removed, the entire gear set, shift forks and shift rods can be lifted out of the lower case. Once the gear set assemblies have been removed, lift out the diff assembly.
What remains in the lower case are two large shift lock out beans and one small one on the end of the middle shift fork shaft or 3rd/4th shaft. DO NOT LOOSE THIS SMALL BEAN or there will be much grief later.
The small bean.
The three beans.
Using a 10mm socket in a universal, remove the shift translator coupler to shift shaft screw. This one is special.
Remove the shift shaft from the lower case.
Done for now.
Bernice
:clap::thumbsup::worship: