Overdrive shift

Spazola · Post by **Spazola** » 31 Oct 2011, 13:35

I pressure washed my 88' 240 sedan engine and undercaraige and now my shift light stays on and it won't shift into high gear. What should I look for?

Post by **billofdurham** » 31 Oct 2011, 14:28

Have you pushed the overdrive button on the side of the gear shift?

Bill.

Spazola · Post by **Spazola** » 31 Oct 2011, 15:22

yeah i tried that. didn't work this time.

Post by **billofdurham** » 31 Oct 2011, 17:37

I always try the easy way first. Now it's time to get down and dirty.

Pressure washing may have dislodged the wire on the overdrive solenoid which is on the left side of the transmission housing. There is only one wire, white in colour, as it earths (grounds) through the gearbox casing.

Bill.

shegarty · Post by **shegarty** » 01 Nov 2011, 09:58

billofdurham wrote:Pressure washing may have dislodged the wire on the overdrive solenoid which is on the left side of the transmission housing

if this is the case you can try reconnecting the wire or running a completely new one - you might be better off just modifying the solenoid to allow for OD to be continually available and not routed through a relay and the switch on the shifter - this mod is only advised for automatic tranny's and NOT manual as some damage can occur in reverse on the manual trans

there is a good write up here (scroll down near the bottom) on how to accomplish this - see attached pic as well - don't forget to remove the inner o-ring or all your work will be for not!

for most driving purposes there is no need to be able to manually disable OD so this fix works well - did this on my 90 740 almost a year ago and still works great

you can also find a replacement plate at IPDbut modifying the solednoid is a very easy fix with a dremel and some diamond tip bits

Spazola · Post by **Spazola** » 04 Nov 2011, 05:17

upon further inspection, I am blind. I checked fuses (twice), wires, relays solinoid wires and shifter button. Nothing. So I started over and bingo. there was a hairline crack in a fuse. Can't believe I missed that. Oh well I learned alot. Thanks for your help. By the way the info you gave me on throtle position sensors was very helpful. Now she runs smooth shifts out saves gas. Woo Hoo. Now off to the suspension problems. uggg

Post by **Choguy03** » 04 Nov 2011, 09:15

The never ending list of things you want to fix. Haha.

Post by **billofdurham** » 04 Nov 2011, 12:33

I learned, the hard way of course, never to look at a fuse and say it's OK.

"Always use a meter or a test light for complete accuracy." The advice given to me some 25 years ago by an auto-electrician when I took my dead car to him, after several frustrating days of electrical probing, and he fixed it in 3 minutes plus a few seconds.

Bill.