Transmission Position Switch on 3.0

andrewwynn · #1 08-30-2018, 05:02 PM

Seems my position switch has failed.

I got a trans failsafe error after the battery went flat from sitting too long, I was able to reset the error but noticed that my dash didn't match my selected gear properly. (Example showing 54 vs D or nothing at all).

Took a while to find the proper submenu in the foxwell NT510 but sure enough found the real-time data from the transmission and the open/close of the four lines are wonky: inconsistent. I'm concerned the problem is actually inside the TCM which would be far easier to replace than the range/position switch which is inside the damn transmission!

Has anybody actually removed one of these ? I have a shop manual but it only includes how to replace the range switch on the V8 where it's external!

It looks like the switch is pinned in with a pair of roll pins and of course I need to drop the bottom off the transmission to get to it. Bringing me to phase two: since I have to remove the transmission fluid and pan, should I put the same fluid back in or replace with new fluid and filter? Until this failure the transmission has been flawless and I push it hard.

I'm considering making an extenal switch box to assign which gear I'm in until I take the transmission apart it's pretty simple BCD coding. I can buy a $5 BCD 4 bit switch and label the magic spots for PRND. Would be a LOT LESS work than dropping the transmission pan!

I can usually get the switch to register properly by shifting in/out of gear until the wiper cleans off the contact but it seems more than just a dirty contact because sometimes a contact is closed when supposed to be open (as if wiper is bent).

I got some really horrible shifts when it first wigged out and I was terrified my transmission was shot but now I'm confident it's either the position switch or the TCM which I've seen on eBay for like $25.

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andrewwynn · #2 09-10-2018, 02:24 PM

Bump: nobody has replaced a transmission switch on a 3.0 E53?

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RRPhil · #3 09-10-2018, 06:01 PM

https://xoutpost.com/837639-post1.html

Phil

upallnight · #4 09-10-2018, 09:20 PM

Quote:

Originally Posted by RRPhil

https://xoutpost.com/837639-post1.html

Phil

Looks like a lot of work.

andrewwynn · #5 09-10-2018, 11:53 PM

Well I don't have to remove from the car. Does seem like I have to remove the solinoids rack so that's annoying.
I'm hoping my problem is in the wiring or TCM. I can swap with my wife's cove l clone car and see if the transmission switch error magically moves to her car.

Then I can just buy a used TCM for $25 on eBay.

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upallnight · #6 09-11-2018, 12:24 AM

I had to replace the selector switch on my E34 touring. The good news the switch wasn't inn the trans. The bad news it was secure with a shear bolt that when the head sheared off it left a tapered end.

srmmmm · #7 09-11-2018, 09:39 AM

Make sure the transmission harness connector is clean. Dirt and moisture can cause the pins to corrode and send false signals causing all kinds of weird behavior. I wasn't able to shift mine into park after a heavy rain one day. I'm an advocate of sticking with the original fluid. Capture it and screen it before returning it to the transmission. Go ahead and replace the filter and just top off accordingly. I'm still on my original.

2002 X5 3.0 348,150 miles
2014 428i 40,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird Under restoration - Long block assembly finished

andrewwynn · #8 09-11-2018, 10:55 AM

I'm going to do that today if I can find the connector. I'm going under to change out a defective on arrival O2 sensor I'll be "right there".

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andrewwynn · #9 09-11-2018, 12:40 PM

Finally found the noso clear directions in the shop manual. I couldn't find them before because it's in a section clearly marked 4.4 engine.

Fig. 100

Drive spring pin (1) out of transmission switch (2). See Fig. 101 . Withdraw manual shift valve shaft (3) from
transmission only so far that transmission switch (2) can be removed. DO NOT remove parking gear rack. DO NOT move parking gear rack more than 10 mm; if necessary, secure with pointed pliers. Release notched disk on parking gear rack. Remove transmission switch (2) with detent disk.

Fig 101

Remove transmission switch (1) from detent disk (2). See Fig. 102 . Upon installation: bore holes for spring pin
in transmission switch (1) must overlap with bore holes of detent disk (2) and manual shift valve shaft.

Fig. 102

Installation: attach parking gear rack (1) from rear in detent disk (2). See Fig. 103 . Slide in manual shift valve
shaft. Drive in spring pin. During entire installation work, journal (3) must be aligned vertically to manual shift
valve shaft. After installation of detent spring, ensure that parking lock functions correctly. Press journal (3)
forwards into "P" position, rotate propeller shaft and check that locking pawl engages.

Fig. 103

andrewwynn · #10 09-11-2018, 12:45 PM

What is not clear is do I have to disconnect the selector lever if I'm just pulling it out sideways enough to remove the transmission switch.

Also the switch comes with two roll pins and only ones is mentioned in the repair guide. I think one pins the shaft in and one pins the switch to the shaft it's unclear and I would love to know before I start.

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