Another E4OD problem

[quickster]

Hows it going all. I'm having a shifting problem in my '91 F350 rwd with the E4OD. I posted a while back about how the speedo always reads 3-8mph faster than the actual speed. I checked it against my GPS. I also read that in my year truck there is some type of magnetic assist in the speedometer head that could be a problem. When I am running down the road, at 35mph exactly it will shift into overdrive. That is according to the speedo-- not the actual speed because it is off a couple mph. Now I have changed the VSS with the propper gear, just installed a new TPS , and a new speedo cable. I have been doing alot of preventative maintenance to the truck and this is the last thing to fix. I also put in a new torque converter, filter and fluid.
If I run in the 35mph area it jumps from 4th to third back to fourth. quite a bit, so around town I ride with the OD off. Or stay above 40mph -but can't do that around town.
Anyone else ever have this happen, or if any trans guys out there can help me out. If I can get this worked out I will be done.
I was thinking a junkyard cluster, but I'd like to keep mine because it's in nice shape. Any help would be great.

 

[Oelmensch]

Mine did the same thing when I first got it, but oscillated between 3rd/4th at 48mph. It was a bad tach sensor in my case, which was fairly apparent once you noticed that at that same speed the speedo suddenly came to life. If your tach isn't acting up it might not be as likely of a culprit.

You mention a new TPS, was it adjusted into calibration when it was installed (0.96V-1.2V on the bottom end IIRC)? I don't know the E4OD and its quirks nearly as well as others here, but I know the output voltage from the signal terminal on those is critical to proper shifting, but that might be more applicable to force/firmness of shifts and downshifting when accelerating.

Hopefully others with more experience can chime in with more detailed advice/questions.

 

[quickster]

I replaced the tach sensor a while ago. I have no fluctuations going on there. The TPS is set at 1.2v. I'm thinking the speedometer because it shifts exactly at 35mph every time. When I pulled the cluster a couple days ago for the speedo cable replacement, there is nothing on the back side that looks like you could possibly adjust. I'm going to clean the electrical connection at the trans today, hoping maybe something will change.

 

[OLDBULL8]

You don't have any problem.

The E4OD will shift into OD at 35 to 40 MPH. All cable driven Odometers/Speedometers are variable by about 5 MPH. That's why most Cities have a 5 MPH speed grace. You should have the Pink gear, IIRC , driving the trans transmitter.

Yes your speedo is magnetic driven. you can't change that.

Digital speedometers are accurate to 1 MPH, there computer controlled.

When the trans hunts ( shifting from 3rd to OD) you always want to keep it out of OD, City driving greatly effects that.

The voltage on the IP TPS is set between .92 and 1.2 VDC in idle position with a hot engine but engine OFF. The lower the voltage, the softer the shifts, higher voltage naturally is harder shift. The WOT voltage cannot be adjusted, it is what it is, as long as it's not above 5 VDC. The voltage is measured with a Digital VOM.

 

[quickster]

Thanks for the reply Bill. I was thinking I was losing my mind not being able to track down the answer for this. And replacing everything was becoming the only way to get it done. 5 mph of slop is a bit much. When I replaced the VSS I put the gear that was on the old one back on to the new one. I think I'm going to pull it out just to check the color again. Thanks again.

 

[trackspeeder]

What you are experiencing is normal for the 89-91 E4OD. You're better off keeping the OD off around town.

 

[icanfixall]

I very seldom use OD when in town. If I need the next gear up from 3rd I use the Gear vendors.

 

[trackspeeder]

I very seldom use OD when in town. If I need the next gear up from 3rd I use the Gear vendors.

That's cheating.

 

[FORDF250HDXLT]

the updated/latter TECA's wont do this.she'll hold onto 3rd or 4th.no hunting.you could always update.though pressing the od button is free.