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Classic Bimmers
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  #1  
Old 02-09-2013, 06:01 PM
Indy452 Indy452 is offline
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Location: Kansas
 
Join Date: Feb 2013
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Mein Auto: 735i
1987 L7 problems

I need some help with my 87 L7. Every once and awhile the transmission will go into linp mode...you know, the orage icon on the dash that looks like a gear with and exclamation point inside it.

It has good fluid level and when its working it works good. I had it in "S" mode then went to "E" and then it was on next time I drove but having trouble getting it back to normal...any tips?

Thanks...
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  #2  
Old 02-10-2013, 09:14 PM
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IEbimmerguy IEbimmerguy is offline
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Location: Cali
 
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Mein Auto: E38, e23, e3
There's a few things to try first before you start replacing actual parts:
1. Trans fluid condition, is it red, not burnt, and free of particles? (If in doubt just change it with Dexron Trans fluid)
2. Check the 8 pin electrical connector on the drivers side of the engine. (Twist and pull) it should be clean and free of oil. For the heck of it, clean it with brake cleaner or electrical parts cleaner.
3. Check the wiring and switch on the console for the sport/Econ.
4. Clean the switch under the black rubber boot on the throttle body. There will be two of them, the one you want is the one with the round hole in it. Clean with electrical cleaner and move the throttle as you spray the cleaner. (This switch has caused issues with my EH Trans on my personal 1986 735i)
Does the transmission shift firmly without slip or hesitation when you're not experiencing your "problem"?
I'm sure there will be others that will chime in with their own recommendations, let us know how it goes.
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  #3  
Old 02-11-2013, 05:06 AM
Indy452 Indy452 is offline
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Location: Kansas
 
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Mein Auto: 735i
Quote:
Originally Posted by IEbimmerguy View Post
There's a few things to try first before you start replacing actual parts:
1. Trans fluid condition, is it red, not burnt, and free of particles? (If in doubt just change it with Dexron Trans fluid)
2. Check the 8 pin electrical connector on the drivers side of the engine. (Twist and pull) it should be clean and free of oil. For the heck of it, clean it with brake cleaner or electrical parts cleaner.
3. Check the wiring and switch on the console for the sport/Econ.
4. Clean the switch under the black rubber boot on the throttle body. There will be two of them, the one you want is the one with the round hole in it. Clean with electrical cleaner and move the throttle as you spray the cleaner. (This switch has caused issues with my EH Trans on my personal 1986 735i)
Does the transmission shift firmly without slip or hesitation when you're not experiencing your "problem"?
I'm sure there will be others that will chime in with their own recommendations, let us know how it goes.

Hey, Thanks! Thats what I'm looking for...I really appreciate these tips.

As for the transmission shifting fine etc...yes. Its a solid transmission....never slipped or acted up anytime other than this silly electrical problem. I'll take your advice and let you know how it works out.

BTW, is there a way to flush the tranny fluid other than draining through the drain plug? On my Volvo's I have a method of unhooking the line from the radiator and adding a length of hose and once the car is started, I add fresh fluid while the old is pumpped into a 5 gallon bucket until the fluid looks fresh.....this has worked on Volvo's but not sure on BMW? Its crude but effective.

Thanks again!
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  #4  
Old 02-11-2013, 07:14 AM
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IEbimmerguy IEbimmerguy is offline
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Mein Auto: E38, e23, e3
As far as the fluid change, I wouldn't recommend you remove the hoses and add new fluid that way. You're bound to be either too fast or slow with the filling or may do more harm than good.
BMW gives you a drain plug on the pan, so the best way is to drain and fill, drive for a few miles, then drain again, remove the pan and filter, and another fill with fresh fluid. That's the most common way to get a through fluid change.
I reread your original post. I'm thinking you might want to start at your sport/Econ switch on the console. Possibly have a bad switch or wiring damage.
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  #5  
Old 02-11-2013, 07:58 AM
Indy452 Indy452 is offline
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Location: Kansas
 
Join Date: Feb 2013
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Mein Auto: 735i
Quote:
Originally Posted by IEbimmerguy View Post
As far as the fluid change, I wouldn't recommend you remove the hoses and add new fluid that way. You're bound to be either too fast or slow with the filling or may do more harm than good.
BMW gives you a drain plug on the pan, so the best way is to drain and fill, drive for a few miles, then drain again, remove the pan and filter, and another fill with fresh fluid. That's the most common way to get a through fluid change.
I reread your original post. I'm thinking you might want to start at your sport/Econ switch on the console. Possibly have a bad switch or wiring damage.
My thoughts as well on the switch...Seems when I mess with that the symptoms appear.

Dexron 3 is fine in these then?

Thanks for the help...
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  #6  
Old 02-11-2013, 08:50 AM
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IEbimmerguy IEbimmerguy is offline
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Location: Cali
 
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Mein Auto: E38, e23, e3
Yes Dexron 3 is good. Some people have reported issues with using the new Dexron 6?, I think it's too thin....
Look for one of the Castrol Dexrons, and check the back of the container for compatibility. I say this because the name Dexron is, or has been eliminated since GM hasn't renewed licensing or something like that.....
I would clean your switch or simply replace it. You'll find it at a salvage yard by the dozen, in both the e23 and e28.
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