1989 635csi automatic will not shift into 4th gear

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Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

Hello,
I have just purchased a 1989 635csi automatic that has been sitting for a little while. I have spent the last few weeks sorting her out and she is running extremely well. However, the 4hp22 transmission will not shift into 4th gear regardless of which mode is selected. I drained the fluid which was perfectly clean and pulled the pan to investigate. Everything is spotless. This makes sense as the previous owner told me the transmission had been rebuilt.
The transmission operates perfectly in the first three forward gears and reverse. The fluid level is correct. Checked with the car warm and running. I am leaning towards it being a problem with the transmission control module. I am by no means an expert and would love to hear your thoughts on this issue.
Thanks in advance to those who have some information to offer!
Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

Re: 1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

Sorry for the ad on. I also unplugged the harness and cleaned all of the connecting pins and recepticals with electronics cleaner.
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: 1989 635csi automatic will not shift into 4th gear

Post by plip1953 »

It sounds to me that it thinks it's permanently in Sport Mode.


A quick Google and this popped up. Not sure if it might be any help.

https://blog.bavauto.com/8097/bmw-autom ... 1-e32-e34/
Phil
__________________________

1988 Highline 635 CSi
Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

Re: 1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

I am fairly convinced my problem is in the TCM (Transmission Control Module)
Just opened up the glovebox and the only boxes above it are the Engine and the Airbag Control Units.
Can someone tell me where to find the TCM on a 1989 635csi? It seems they moved it for this year.
ssf1342
Posts: 44
Joined: Tue May 21, 2013 1:06 am
Location: WA

Re: 1989 635csi automatic will not shift into 4th gear

Post by ssf1342 »

Kamps16 wrote: Mon Apr 13, 2020 6:15 pm I am fairly convinced my problem is in the TCM (Transmission Control Module)
Just opened up the glovebox and the only boxes above it are the Engine and the Airbag Control Units.
Can someone tell me where to find the TCM on a 1989 635csi? It seems they moved it for this year.
On my '88, the TCM is located on the driver's side inside of the lower dash on the left (same side but above the hood release). http://bigcoupe.com/phpBB2/viewtopic.php?f=2&t=29420 Scroll up 7 posts from the bottom & you will see a picture of the location of the TCM.
'03 530i auto w/sport pkg 134,369 miles
'99 740il 6-spd 223,072 miles
'90 535i 5-spd 339,399 miles
'89 635csi auto 183,xxx miles
'88 635csi auto 322,342 miles

Gone:
'85 735i auto 181,xxx (California-approved "Gross Polluter")
Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

Re: 1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

Excellent. Thanks. Just located it. Bosch 0 260 002 039. Purchased one on ebay. Will let you know if that is the fix. Checked all of the connections at the E/S/321 switch and everything looks solid there. Will keep you posted on this situation. Hopefully a new TCM will do the trick. Fingers crossed!
Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

Re: 1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

Transmission Fixed!
I waited patiently for the new TCM and installed it as soon as it arrived. This did not fix the 4th gear issue. My car drove the same with only 1st, 2nd, and 3rd gears available. I had noticed that the temp and gas gauges had gone dead along with the service indicator and gear indicator lights. They would intermittently come to life but only for a few moments. It dawned on me that this the transmission issue could possibly be related to this electrical problem.
I removed, cleaned and reinstalled all of the ground wires near the battery. Gauges were still dead.
I removed each of the fuses and replaced them hoping to get a better electrical connections. With that, the SI lights and the gauges came on and have stayed on since. I cycled through the transmission switch and the 3,2,1 light came on when it was selected. I hadn't seen that before.
Next was a successful road test with a perfectly functioning 4th gear!
My conclusion: it is possible to lose a fuse that will prohibit the use of 4th gear.
Would love to know if any of you have ever experienced this?
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: 1989 635csi automatic will not shift into 4th gear

Post by plip1953 »

Wow, great detective work. And as you suggest, it would be very odd if no one had ever come across this problem/solution before.

Out of interest, what is the location of the fuses that you refer to?

If anyone has a technical explanation as to why non-functioning dash lights would appear to force the gearbox to default to Sport mode, I for one would be very interested to hear it.
Phil
__________________________

1988 Highline 635 CSi
Kamps16
Posts: 18
Joined: Sat Apr 11, 2020 8:40 pm
Location: Falls Church Va

Re: 1989 635csi automatic will not shift into 4th gear

Post by Kamps16 »

Hi Phil,

I was a little pressed for time and reset all of the fuses one by one in a fairly rapid succession. I did not notice which specific fuse did the trick. I suppose I could go back and see which fuse will kill the gauges and 3,2,1 light. Probably for another day.
75r6q3
Posts: 14
Joined: Sun Mar 01, 2020 11:05 pm
Location: Massachusetts, USA

Re: 1989 635csi automatic will not shift into 4th gear

Post by 75r6q3 »

I’ve been having this exact issue and it’s been on and off since day 1. Sometimes in the winter it fixes itself. I’ve been to the local BMW mechanic several times, but the issue still isn’t completely gone and they haven’t quite located the issue. I’ll try the fuse thing when I do have the time. Thanks for posting!
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