Well, let's just say I'm really determined to fix this but not break the bank.
Symptom:
1st. Rpm's drop to no reading periodically at the tach creating a terrible shifting problem at times. (tach sensor)

2nd. And then after about 20 minutes or so the rear anti-lock light comes on, and all bets are off for ANY normal shifting. (speed sensor)

I have searched and read prior posts reguarding both symptoms and since I'm going to be keeping this truck a long time (3years+). I'm thinking just replacing both sensors, that way they are new anyway. Also someone talked about a wire needing repaired in the RABS, just wondering where the break was located at keeping the signal from being sent back..?

All comments of course greatly appreciated as usual..

 

I'd replace the tach sensor (that's usually it), but maybe do more investigating on the anti-lock. If you have a manual (not the one in the glovebox) for the truck, it should tell you how to get the anti-lock codes out. If I remember right, there's a wire down by your left foot that's not hard to find. I did this a while back and didn't get any codes (a clue). It turned out there was a bad connection near the fusepanel and the antilock module (above your right foot) wasn't getting any power.

 

Spectramac,
I haven't bought the manual yet, scared to if it's going to be this much hassel and so unreliable to own it, might as well by a 5spd truck maybe..?

Still acting up though. I drove 17 miles to work it was fine until I pulled off the freeway. Three blocks later the tach drops to zero and the rear anti lock light comes on and it shifted terrible for next four blocks to work.

When I leave to go home I pull out of the basement parking lot to head up the ramp and the tranny doesn't recognize what to do, so I manually put it in low and it pulls me out of there... Thank goodness..! The rest of the way home it does ok with no Tach loss signal or anti-lock light.

I'm not giving up yet but I actually stopped to looked at an 88 F250 XL 7.3L SC 4x4 FIVE SPEED Manual today, but the engine seemed to be 2/3rd's the power of my 90'w/ the E4OD, and the front seal leaks. Also the temp was on the "M" of normal with a brand new radiator I might add..

I plan towing a 9K trailer, so should I cut my losses on the E4OD now since I will be towing that much.... And don't want to be broke down halfway up a mountain pass. Should I just buy the 88' 5spd truck 2500 US...

I know you can't see both trucks, but which one would you rather have considering you had to tow 9K.... Btw the 90 is a Lariat loaded. The 88 is an XL a/c cruise tilt ps, needs brakes and possible ball joints. The body & paint is quite a bit better on the 88 too though.

That's what I'm faced with now , any more input would be great.

 

For towing, you would be far more reliable with a 5 spd. Those autos are hard to keep on the road as it is. They just burn out faster with a trailer.

 

I found out an old neighbor (Bob) of mine 25 years ago was still doing the trannies at the local Ford dealership... Wow, was I happy he was still working there.
The service writer said that Bob would take the pan off during his inspection of my E4OD. I told him to have Bob call me if he feels that needs to be done first, because I seriously doubted that the problem was internal and I felt Bob would find it outside. He found it to be a ground that the ABS shared with the module and was barely making contact. So I will keep the E4OD as the tow beast and upgrade to a 28-30K tranny cooler. Plus I now have two back up sensors... lol(Tach & ABS..:-)

 

I had a few problem with my trany and it was a nightmare with the wiring. The problem with the RPM drop was caused by a bad connection at the alternator.

You could also have a problem with the wires. At one time I had wires that got worned down on the drive shat and caused a short with the wire going to the soleinoid pack.