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transmission work at the Forbes' place

66K views 69 replies 24 participants last post by  freightdogfred 
#1 ·
Randy and I did the two service actions on my transmission today. The one for the shift catch pins, and the one for the 5th and reverse gear locking pin bushings. 5 new bushings total, 5 new sealing caps, 3 new springs and 3 new pins. I wish I would have bought a new locking pin for 5th gear; mine is clearly worn unevenly. If you're doing this work, buy new locking pins for reverse and 5th gear. FWIW, the service bulletin says you need the repair kit 23.11.7.542.726, but in reality you need two of them; there's only one bushing per kit and you need two. Also need all the right tools, which I bought (4 drifts and a small slide hammer).

In stock form, all of the shift catch pins slide in the machined bore in the transmission case. I guess it's no wonder that they can develop problems with sticking in the bore; different materials with different expansion rates, and the bore doesn't really get wetted. The two forward ones were both quite dry, the rearmost one was a little wetter. The repair kit comes with 3 bushings (look to be lined with a PTFE mix), 3 new catch pins, 3 new springs, and 3 new sealiing caps.

Everything went without a hitch. Auxiliary parts needed: all exhaust fasteners to remove the midsection, and the gaskets at the header end since they're graphite and mine were pretty much toast (at 31,000 miles). Looking at them, I'm surprised more people don't develop exhaust leaks at this point. Whatever slight binder is in those appears to melt a bit over time. I didn't take pictures, you'll have to take my word for it. :)
 
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#2 ·
out with the old catch pins...

Punch a hole in each sealing cap, screw in the BMW mini slide hammer tool, and take out the sealing caps. 3 of these in the top of the transmission.



Pull the spring and catch pin out. We used the BMW mirror switch removal tool to lift the catch pins out; they're hollow inside.



Old sealing cap, old spring and old catch pin.

 
#4 ·
In with the new part 2...

Use another BMW drift tool to install the new sealing caps.



We wound up tweaking this drift a tiny bit with the die grinder because it didn't want to come out of the sealing cap without taking the sealing cap with it. Just took a hair off the diameter of the tip, and chamfered the tip.



Put the cap on the drift and tap it into place.



One done (leftmost in the picture), the other two are the same deal.

 
#5 · (Edited)
reverse and 5th gear locking pins

I didn't take as many pictures here. This one shows the locking pin for reverse already done (blue cap at top center). It's essentially the same deal as the shift catch pins except there's an internal snap ring holding each cap. Remove the snap ring, punch a hole in the plastic-coated metal sealing cap, and remove it with the slide hammer. The sealing cap is removed for 5th gear in this picture, and the end of the spring is visible. It's the bore beneath the blue sealing cap for the reverse locking pin.



Remove the locking pin (BMW mirror switch removal tool used again here), then carefully remove the old unlined bushing by tapping a small screwdriver or the like between the bushing and the bore.at the bushing's split. One you've got enought of it pried up, you can pull it out with needlenose pliers.



Unlike the old bushing, the new one is lined (presumably a PTFE mix). the 5th gear locking pin was sticking on the old bushing pretty badly. It slides easily in the new bushing.



Use another BMW drift tool to tap the bushing into place. There are different drifts for the 5th and reverse gear bushings. Same diameter but different final depth.



Correct depth is when the large diameter of the correct drift hits the transmission housing.
The one that goes deeper (023) is for the reverse bushing, the shallower one (022 shown below) is for the 5th gear bushing.

 
#6 ·
As usual, many thanks to Randy for his help and the use of his garage and lift. MUCH easier than me doing this at home on jackstands.

And of course, thanks much to Sue and Randy for dinner and a margarita. :)
 
#11 ·
You're welcome, as always :)

At least we finally got that project off the list; now you're ready for a nice long drive...
 
#7 ·
Oh, not pictured... the 5th drift to tap in the sealing caps for the 5th and reverse locking pins. IMHO you don't really need that one, and the springs are strong enough on those pins that you need to push on the caps while installing the internal snap rings anyway (so need something smaller than the drift, say a 1/4" socket extension).
 
#15 ·
Bummer. Hopefully I won't be replacing the bushings annually. Were the bushings installed correctly? It looks to me like it's pretty important that they're oriented correctly (split should be to the side of the transmission, not fore or aft). One of the reasons I decided to not let the dealer do it.
 
#16 ·
well?

any noticable difference shifting?
 
#20 ·
Not that I can tell, but I didn't expect any difference in feel and I've only driven it home from Toledo. Might be a wee bit easier going from 4th to 5th.

The problems I've had engaging 1st and 2nd gear have been spotty... most of the time it wasn't an issue, but there were times when it just wouldn't go into 1st or 2nd gear. Presumably because one or more catch pins were stuck in their bore. Makes me wonder what happens when this occurs in an SMG car.

The probability of it being a problem was increased in hot weather. The real test will be the Homecoming trip; it acted up several times last year.

I suspect it's less likely to occur in the S52 cars just by the virtue of having no undercover and hence more cooling of the transmission. No data to back that up. I like running with my undercover because I live on a dirt road.
 
#17 ·
I understand the 5th/reverse lockouts. Those springs case the shifter to move back to center in the left/right axis.

What are the others for? The same in the fore/aft axis?

My race car has the 5th-gear left/right pin sticking when cold, but it's fine when warm, so I haven't bothered to pull the tranny and fix yet. It warms up enough on the 1st lap. But I haven't noticed any other symptoms and until this post, I wasn't aware of the other set of pins. Just curious.
 
#21 · (Edited)
Not the same as the 5th and reverse issue, see the service bulletins. Basically each of the three from-the-top pins can be in one of three detents on the top of the forks. If a pin gets stuck in its bore, you can't move that fork. In my case, the pin for 1st and 2nd gear liked to get stuck while it was in the center detent. If you try to force it, you risk damaging that pin and/or its bore. The pin is furthest out of the bore when its in a detent.

When doing this, I had the thought "This can't last forever", because eventually the bushing lining will wear away. Maybe that's what has happened with felonious' car. But at least now there are bushings that can be replaced. To me, ZF could've made some minor changes to the pins to make this less likely. Alas they didn't. The engineer in me says they should've put more meat in the pin walls (make them stiffer) and then chamfered the outer edges of the open end.

I've yet to contect Jim Rowe to see if he's ever done anything to address this issue.
 
#18 ·
during this project the other items I palnned to replace are the ball/flex/joint connector (whatever its called ) on the end of the shift rod. as well as the (goblaglich) driveshaft flex joint. and shift linkage support front bushings.
 
#24 ·
They're in the repair instructions. You don't need 23 0 170 or 00 1 450. For both repairs, you need 23 0 490 (the slide hammer). For the catch pins you need drift 23 3 110 and 23 2 360. For the 5th/reverse locking pin bushings you need drift 23 4 022 and 23 4 023. You don't really need drift 23 4 021, but I bought all three as a set (23 4 020).

Obviously need other tools to get the transmission out. I didn't document that because it's pretty much like removing any RWD transmission. Many torx bolts on the bell housing, disconnect driveshaft from guibo, need a bent screwdriver tool for the 'bitch clip' to get the carrier arm off the transmission, need to remove the slave cylinder from the transmission, need to remove the exhaust midsection, etc. On the S54, you need to remove the intake manifold so you can see the starter from the top and get a little more light underneath. Engine should be supported too, which can either be done from the top via the engine hook or Randy's preferred method when the car's on a lift: a stand from underneath (which is how the 2 dealer's Randy and I have seen do it). Randy has a transmission jack, which makes getting the transmission on and off very easy when the car's on the lift.

I'd say you don't really want to do this in your garage without a lift and transmission jack. It's worth paying a shop to do it if you don't have these things. The dealer if you don't want to pay for tools too. There's one retaining screw on the steel bellhousing gasket that's a PITA to get at even with the car on the lift, and it has to be removed/replaced because that gasket is forward of the flywheel/clutch (can't be taken off with the transmission). The cat and O2 sensor bung make it a pain to get to it. It'd be easy if the heaers were off, but that's more work.
 
#26 · (Edited)
I'm always amazed at the list price of the BMW tools, although it makes some sense given the small potential market. *Insert your own BMW conspiracy theory here*:D

Just out of curiosity, what is a ballpark figure for the plethora of special BMW tools needed for this job?
 
#28 ·
I honestly don't remember. I bought the slide hammer and two of the drifts so long ago that Randy had been using the slide hammer for other things for a while. :) I think the set of three drifts for the 5th/reverse work was about $75. You can of course just look it up online.
 
#32 ·
I guess I was wrong about feeling a difference. I haven't driven the car much, since I'm in the middle of a multi-day detailing. However, on Monday when I pulled the car back in the garage, it was much easier to get it into 1st gear than it used to be with a cold transmission. I wasn't thinking about it, but got the "whoa, that was easier than usual" feeling. Keep in mind that I was having trouble with the 1st/2nd pin already... your experience may vary. It struck me unexpectedly, so I had to repeat it a few times just to be sure. It's definitely easier getting into 1st and 2nd gear now. Let's hope it stays that way at least until I'm due for a new clutch.
 
#33 · (Edited)
I didn't quite understand the way to orient the bushing splits . could you clarify what they mean in the work instruction when they say in the direction of travel? you said to have the split to the side of the tranny. left or right?
 
#36 ·
Problem Just Showed

The fifth gear problem has made itself an irritation on my 2000 M Roadster with 50k miles.

Of course my car is well outside the 6 year CPO warranty.

The December 2006 cut-off date published by BMW has expired.

Has anyone had recent success getting BMW NA to make the repair without charge?
 
#39 ·
Wow, thats really cool.

So my 5 speed leaks fluid from the shifter input shaft. What kinda work would that be to fix?
 
#40 ·
Not too bad...







 
#41 ·
I just completed the Shift pin service and boy does it make a difference. Selecting 1st gear at a light was always a chore. Now it just slips right in there.

I had a local shop machine the required drifts to specs that were posted on the board.



I then manufactured a slide hammer to remove the caps.


I must say that this service is a little more effort than I expected. The 3 top pins were very simple but the 5th and Reverse where a bit more trouble.

The reverse pin came out with no trouble but the 5th gear pin took quite some work to get it out.

The old sleaves were also quite a bit of work to remove. I almost managed to get one to slide further into the gearbox before getting it out and you really need to hammer on the drifts to drive the new sleaves into place.

Tip for putting the 5th and reverse caps on..tap them part way into place then put the clip on top and then continue to drive the cap home.

I found that these plastic covered caps would not seat until the clip was there to hold them. otherwise they just pop back out a bit.
 
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