Well after getting the car back from the mechanic I eventually sent it to that is He also found a transmission leak, replaced the transmission cone and seals....

Before RPM's... 80kph = 2600RPM, 90kph=2900RPM, 100kph=3100RPM, 120kph=3600RPM, 130kph = 4000RPM, and the engine / transmission sounded really stressed.

After RPM's... are 80kph = 2000RPM, 90kph=2200RPM, 100kph=2400RPM, 120kph=2600RPM, 130kph = 2900RPM 140kph=2900RPM

I've not been faster than 140kph, yet.... Will do when I find a straight, safe and clear stretch of road, about 3am should do

But what a difference, the engine sound so relaxed now!

Hope I can look forwards to better fuel economy and the engine can look forward to a long stress free life!

 

how much did that run you? My overdrive works intermittently. I'm going to try replacing the relay first before I delve deeper.

 

on my 740 auto I have done the button $10. and OD worked great for long time, replaced relay $35. and worked for 6 more mos. now it is acting up agin and i suspect the solenoid $150. is it. IPD sells a blocking kit for $40. that eliminates the never-ending OD curse. My questions are: when a good solenoid engages OD is the solenoid piston/rod extended or withdrawn? If extended, can rod just be cut off and unit reinstalled to have OD 100% of the time?

 

I think it is a Valve inside to soleniod.
The block off plate just combines the 2 ports to like bypass the soleniod.

 

Well it cost me all that I could afford (+an engine tune and new seals) So it will
be a while before anything else gets done on the car... But I've just logged the
mpg's and they are up... from 18 to 23 (US) or 22 to 28 (UK), I figure the savings
I make on fuel will help the solenoid (and the rest) pay for itself!

 

i was workin on a 91 240 with this problem. i found that the od wire going to the transmission had no insulation because it all dry-rotted off. the wire would short out if it touch the transmission causing the od to not work. it saved alot of money insted of have alot of parts replaced

 

The black tubing around the white wire had indeed perished, but the white insluation around the OD wire intself was intact... I was quite amazed how pristine the "old" solenoid looked... I guess these solenoids simply have a set life span? Is there anyting in the transmission that can cause premature wearing though?

 

My '87 (automatic 244 wagon 143,000 miles) overdrive light has been on for a while now and the car won't go into 5th, so now of course we're not doing any highway driving. I saw posts about worn wiring insulation and fuse so I'll check those first. Is there anyway I can tell if it's the solenoid or the relay if it's not the wiring?

Thanks much.

 

Bli745, you don't want to have OD on all the time. I have an 89 740 Estate and the solenoid went on that - I ghetto modded it by running wires with male tabs into the slots where the solenoid used to be to an on/off switch. I now have 8 forward gears! I did manage to leave the switch on once while in reverse, and the car was not happy about that, lots of bucking around and complaining. Plus if I'm in first gear with the OD engaged, leaving a traffic light can be a slow, painful process.