New to me 1990 e350 seems to be stuck in overdrive.
The amber button on the dash does not come on, Its slow off the line and sluggish climbing hills.
Going to check the fuse now, but I checked them all the other day and they all were intact.

thanks

 

Took the switch apart and cleaned things up. Got it functioning with the cover off. Discovered one of the springs for the buttons was missing so I'll look for one of those today and put it back together.
See if thats where atleast part of my issue is. Then Ill move onto the fuel guage, sedning unit, etc (another or combo issue)

 

Whether the overdrive is on or off the transmission will start in first gear. The function of the overdrive button is almost nothing below about 40 MPH.

 

Thanks for that.

 

I have a 1989 E250, 351 with E40D with the dash button for the overdrive.
Personally, I always leave it ON because I have already read bad stories about this button. I live in a flat country. But when I attack the climb up a hill and the speed drops, I accelerate all the way for the kickdown to work and thus regain the necessary power to the top of the hill. If my speed gets too high before the top, I take my foot off the accelerator a little while trying to prevent the overdrive from engaging again before the top.
This is my way of using the E40D, I don't know if it is good ? Mark, please, what do you think ?

 

It was designed to run its entire life in overdrive. The way you're driving it is fine.

 

What about the AOD Mark? There are a lot of roads around here where i might drive 45 to 55 MPH for 4 to 6 miles. I put mine in OD on most of those roads and feather the gas when needed to keep it from shifting down. We have very little traffic around here and sometimes if i have to slow to nearly 35 MPH, I can slowly bring it back to 55 without ever down shifting. If the road is under a couple of miles then I just leave it in D. Also to make that shift from D to OD, I will sometimes let off of the throttle just enough for the transmission to shift to OD. I do that thinking that it is less strain on the OD band?
I have heard some people recommend staying in D and only using OD on the highway for long distances.
I have also read that the AOD can be beefed up if needed?
Thanks
I wonder how much trouble it would be to convert an 88 with AOD to a E4OD

 

The AOD was not as tough as the E4OD. I think what you described won't hurt it. Any transmission can be beefed up.

To convert to an E4OD you'll need a stand alone controller since no 1988 vehicle has a PCM that can shift an E4OD. You will also need to modify the cross-member because the E4OD is longer. And you'll need to shorten the driveshaft.