Question about 1991 BMW 5 Series

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1991 bmw 520i transmission goes into 'safe' mode

My car goes into third gear while driving. I can be on 5th and all of a sudden it downshifts to 3rd. the car jerks and the problem only goes away after switching off the car and letting it sit for a while. this happens about once a week. I was told that this is a 'safe' mode so that the transmission doesnt get wrecked? what causes this and how do i remedy it?

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  • ahmed520i Apr 25, 2009

    i have the same problem. the transmition shifts down by it's self.

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Quoted from BMWE34.network
" Transmission locks in "limp" mode - 3rd gear so you can "limp" home or to your nearest dealer."

"Things to check before even contemplating a transmission overhaul:
Check electrics - Alternator and battery.
Replace DME Relay and Fuel Pump Relay - not expensive.
Remove disassemble, clean and reassemble gear selector switch - If it looks beyond saving, replace ($200)
Service the transmission ($130 from a specialist) and check/replace transmission speed sensor ($90)"

Posted on Feb 21, 2011

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