There are plenty of threads on the shift pin service on ZF transmissions. After Googling it, I've only seen a handful of references to a similar problem on Getrag boxes where the shifter doesn't return to the neutral position between 3rd and 4th from the 5th gear gate.
UPDATE: DIY in post 20.
The transmission I'm working on in particular is a Getrag S5D 250G from a 2000 323ci. When moving the shift lever side to side, the reverse gate is nice and springy and even the 1-2 gate has resistance, but 5th gives me nothing. It's hard to tell it apart from 3-4 and that means potential mis-shifts into 5th when looking for 3rd (or the potentially disastrous opposite).
DISCLAIMER: I'm new to servicing transmissions, so I've had to make educated guesses about the functions of various parts.
I looked at the various springs I can access from the outside of the trans case and there are three springs (#19 in the picture) under the sealing cap that press down on three balls. It seems like there are detents in each of the three shift rods to accommodate them. I guess they're there to resist shift rod movement so as to hold the gear.
http://www.realoem.com/bmw/showparts.do?model=BM33&mospid=47709&btnr=23_0129&hg=23&fg=15
It looks like the locking pin and spring (#3, #4) will fit against the detents in the selector shaft and provide the "in-gear" feel as the selector rod moves in and out. Seems somewhat redundant with the 3 springs+balls above, but I assume it's a lot better at keeping the gearshift in place.
I've deduced that #9 and #11 in the pic below are the reverse and 5th gear return springs, respectively, so I'm going to pull those out and replace them along with the caps and locking pins. The drawing is misleading, but it looks like the roll pin (#5) sits on the cam (#4), which moves between the two locking pins (hence the beveled edges on the pins).
http://www.realoem.com/bmw/showparts.do?model=BM33&mospid=47709&btnr=23_0128&hg=23&fg=15
Here's a much better picture from a post on m3forum where a member was converting the M3 Getrag transmission from SMG to manual 6spd. In that conversion, all of the springs and locking pins have to be added back. The cam is #1 as labeled in the pic and the wheel on the end of it is the roll pin, which is resting between the two locking pins.
Original post: http://m3forum.net/m3forum/showpost.php?p=3416160&postcount=15
Just in case, I'm going to service both the 5th and reverse gear pins. I will be reusing the washers and snap rings.
Parts list:
2x 23127527439 Sealing cover
1x 23311228393 Reverse gear compression spring
1x 23311228392 Reverse gear locking pin
1x 23311224215 5th gear compression spring
1x 23311224130 5th gear locking pin
DIY to follow. Any input would be greatly appreciated.
UPDATE: DIY in post 20.
The transmission I'm working on in particular is a Getrag S5D 250G from a 2000 323ci. When moving the shift lever side to side, the reverse gate is nice and springy and even the 1-2 gate has resistance, but 5th gives me nothing. It's hard to tell it apart from 3-4 and that means potential mis-shifts into 5th when looking for 3rd (or the potentially disastrous opposite).
DISCLAIMER: I'm new to servicing transmissions, so I've had to make educated guesses about the functions of various parts.
I looked at the various springs I can access from the outside of the trans case and there are three springs (#19 in the picture) under the sealing cap that press down on three balls. It seems like there are detents in each of the three shift rods to accommodate them. I guess they're there to resist shift rod movement so as to hold the gear.
http://www.realoem.com/bmw/showparts.do?model=BM33&mospid=47709&btnr=23_0129&hg=23&fg=15
It looks like the locking pin and spring (#3, #4) will fit against the detents in the selector shaft and provide the "in-gear" feel as the selector rod moves in and out. Seems somewhat redundant with the 3 springs+balls above, but I assume it's a lot better at keeping the gearshift in place.
I've deduced that #9 and #11 in the pic below are the reverse and 5th gear return springs, respectively, so I'm going to pull those out and replace them along with the caps and locking pins. The drawing is misleading, but it looks like the roll pin (#5) sits on the cam (#4), which moves between the two locking pins (hence the beveled edges on the pins).
http://www.realoem.com/bmw/showparts.do?model=BM33&mospid=47709&btnr=23_0128&hg=23&fg=15
Here's a much better picture from a post on m3forum where a member was converting the M3 Getrag transmission from SMG to manual 6spd. In that conversion, all of the springs and locking pins have to be added back. The cam is #1 as labeled in the pic and the wheel on the end of it is the roll pin, which is resting between the two locking pins.
Original post: http://m3forum.net/m3forum/showpost.php?p=3416160&postcount=15
Just in case, I'm going to service both the 5th and reverse gear pins. I will be reusing the washers and snap rings.
Parts list:
2x 23127527439 Sealing cover
1x 23311228393 Reverse gear compression spring
1x 23311228392 Reverse gear locking pin
1x 23311224215 5th gear compression spring
1x 23311224130 5th gear locking pin
DIY to follow. Any input would be greatly appreciated.