Rupunzell
Bernice Loui
Not much magic or special about the shift forks in this gear box, except to check for wear at the ends of the fork. They are usually OK unless worn.
The forks appear to be made of brass except they are magnetic. Not sure precisely what they are made of, could be a brass alloy with iron or brass plated/coated steel or cast iron.
This is the 1st-2nd shift fork. Wear on this shift fork is often moderate.
Opposite side of this shift fork.
3rd-4th shift fork. This is the one that wears out most often. If replaced, replace the 3rd-4th slider too as it will likely be wore out. The wore out slider does not make a new shift fork happy due to the existing wear pattern ground into the used slider. There is a shinny area near the ends of the fork, that is the area where these forks wear.
3rd-4th shift fork, opposite side.
5th gear shift fork often has the lowest amount of wear. Regardless, it needs to be checked and replace if worn.
5th gear shift fork, top side.
Reverse gear fork, top. These are usually OK, but if the reverse gear is abused, they are sometimes not OK which means replacement.
This side of the reverse gear fork does the work of moving the reverse idler gear into position to engage reverse. Notice the fork wear.
This is typical wear at the end of a shift fork. Not too bad.
Best to measure the thickness of the shift fork ends to check for wear. They run about 0.190" or aprox 5mm when new.
This fork is really wore out, measures 0.147". This amount of wear will result in a sloppy fit between the shift fork and slider resulting in excessive distance required to engage gears and the slider might not properly seat into the slider-gear engagement teeth.
M6 x 1.00 Shift fork screw and split lock washer. These are special with a unthreaded grip length near the hex head that works as a proper shear loaded area. In theory, if that area is threaded and shear loaded, it can fail as the external threads act as a stress riser. Don't replace these with anything other than the identical stock Fiat screw or a screw with an identical grip length and grade 10.9 strength rating.
The split lock washer, there have been cracked-shattered (causing the M6 screw to be loose) ones found in this location. The other failure mode, the split lock washer has completely lost it's helical set making it an essentially a flat washer with a split.
In place of the stock Fiat split washer, these toothed conical washers designed for socket head cap screws are used. These have enough spring force, hardness and bit in the teeth to do some good. Since these have no split, they don't fail by shattering as the split lock washers do. Alternatives are Nord-lock or cleaning the internal and external threads and associated parts really, really well with brake cleaner and use loctite.
Bernice
The forks appear to be made of brass except they are magnetic. Not sure precisely what they are made of, could be a brass alloy with iron or brass plated/coated steel or cast iron.
This is the 1st-2nd shift fork. Wear on this shift fork is often moderate.
Opposite side of this shift fork.
3rd-4th shift fork. This is the one that wears out most often. If replaced, replace the 3rd-4th slider too as it will likely be wore out. The wore out slider does not make a new shift fork happy due to the existing wear pattern ground into the used slider. There is a shinny area near the ends of the fork, that is the area where these forks wear.
3rd-4th shift fork, opposite side.
5th gear shift fork often has the lowest amount of wear. Regardless, it needs to be checked and replace if worn.
5th gear shift fork, top side.
Reverse gear fork, top. These are usually OK, but if the reverse gear is abused, they are sometimes not OK which means replacement.
This side of the reverse gear fork does the work of moving the reverse idler gear into position to engage reverse. Notice the fork wear.
This is typical wear at the end of a shift fork. Not too bad.
Best to measure the thickness of the shift fork ends to check for wear. They run about 0.190" or aprox 5mm when new.
This fork is really wore out, measures 0.147". This amount of wear will result in a sloppy fit between the shift fork and slider resulting in excessive distance required to engage gears and the slider might not properly seat into the slider-gear engagement teeth.
M6 x 1.00 Shift fork screw and split lock washer. These are special with a unthreaded grip length near the hex head that works as a proper shear loaded area. In theory, if that area is threaded and shear loaded, it can fail as the external threads act as a stress riser. Don't replace these with anything other than the identical stock Fiat screw or a screw with an identical grip length and grade 10.9 strength rating.
The split lock washer, there have been cracked-shattered (causing the M6 screw to be loose) ones found in this location. The other failure mode, the split lock washer has completely lost it's helical set making it an essentially a flat washer with a split.
In place of the stock Fiat split washer, these toothed conical washers designed for socket head cap screws are used. These have enough spring force, hardness and bit in the teeth to do some good. Since these have no split, they don't fail by shattering as the split lock washers do. Alternatives are Nord-lock or cleaning the internal and external threads and associated parts really, really well with brake cleaner and use loctite.
Bernice
