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ChalesG
03-17-2004, 10:18 AM
Does anyone know if an automatic transmission (non-electronic) from '85 735i fit and work normally on a '86 L7 with electronic transmission ? Please reply soon before i get rid of the '85. Thanks in advance.

Draleu
03-17-2004, 01:37 PM
your tranny? Also I hope you know that you can get one rebuilt for cheap by Joe Gisler instead of putting a used one in and have the same problem again later.

CharlesG
03-17-2004, 09:58 PM
the tranny is shifting hard. I changed oil & filter and still shifting hard. I do have an 85 non-electronic tranny and I am thinking of swaping it with the existing electronic tranny on the 86 L7 if it works. Any thoughts about the hard shifting or the swaping would be appreciated.

Charles
03-17-2004, 10:17 PM
(hard shifting since I got the car). I have just started changing out 1 qt. of fluid, which is moderately dirty, each month with a quart of Mobil 1 synthetic fluid. If that doesn't work the valvebody and ECU are going to Joe Gisler for a checkout and probable rebuild. The problem could be in the Motronic, not even in the transmission itself. Worst case is to pull the tranny and send it to him for a complete rebuild ($650 plus about $75 freight each way). I wouldn't buy someone else's junkyard 4HP22EH problems either!

CharlesG
03-17-2004, 11:04 PM
I am experiencing hard shifting (almost hammer shifting) on both when changing lower gears (1st. and 2nd.) and when backing up. I will be intersted to know if synthetic oil works, for your sake and mine. Let me know how it goes. Thanks for replying and best of luck.

mpax
03-18-2004, 06:14 AM
Have you checked you universal joints in the driveshaft?

Steve: 85 735i, 87 735i, 87 535is
03-18-2004, 08:08 AM
I had the reverse hard shift for six years, until I read hear about suspension stuff. Turned out to be the rear differential mount. Although after fixing that I now need subframe bushings.

tondoman5000
03-18-2004, 10:27 AM
If you have hard shifting- open the ecu and look at the tranny side for bad solder joints. Or- swap out the ecu with a friend and see if that fixes it..

Lars OBG
03-18-2004, 11:50 AM
in 1975. You will possibly have a tranny problem again soon. There was a technical bulletin floating around this board on the "port relief" problem in the early 4HP trans.

Draleu
03-18-2004, 06:22 PM
Hard shiftig is usually electrically related. I have cured mine by thoroughly clean the plug on the tranny and reflowed the joints in the tranny ECU.

CharlesG
03-18-2004, 10:54 PM
Sorry for being ignorant but what do you mean by reflowing the joints in the tranny ECU ? and where would the tranny ECU be located in an 86 L7 ?....In case that doesn't fix it, does an 85 725i tranny fit on an 86 L7 ?....Thanks a lot for everyone's suggestion/help.

Draleu
03-20-2004, 03:32 AM
The ECU is located in the passenger side speaker well if you have a left hand drive car. The ECU box is a combo of Engine and Tranny ECUs.
Take out the ECU box and opened it up. Check all the solder joints and reheat/reflow all the joints that looked questionable. Don't use too high of a wattage iron, I use a 25W one for the big joints and 15W for the small joints. Make sure you don't stay on the joint for too long or you might overheat some of them sensitive SMD components.
As far as whether you can use a non electronic tranny - I don't think you can as the tranny ECU will have to be eliminated to make it work. This is a question for Joe as I am not sure.


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