Auto Trans. "Glitch"?

[imp]

I always figured when an automatic did some real unusual things, it was either low on fluid, or something had failed, never to work properly again until repaired.

1990 F-150, 351W, E4OD trans. Shows 62K, Contractor's truck, bought from him, original owner, likely 162K, can't tell. Last week, once or twice during each use, shifting seemed normal, except trans suddenly seemed to drop down a gear, though I couldn't really tell if it was TCC drop-out, or 4th. to 3rd. gear, happened around 45 mph, at which speed the TCC is usually engaged already. Eng. speeded up, truck kept pulling, it was not slippage. Let off gas, everything went to normal, continued on rest of drive normally. Following few days, same deal, same results. Since then, though, everything is again normal, and this has not repeated.

Would you just leave it alone and use it? If not, what would you do to it? Fluid looks completely normal, nice color, normal stink. imp

 

[Mbrooks420]

Has it been sitting? My Mounty sat mostly unused for the last few years as a second car and a 4 person golf outing car, and it would refuse to shift into 3rd under power for the first 2-3 shift of the day. It did this for a few weeks and went away. I figure something must have worked at way out.

Fluid was clean, and after the first time it did the 2-3 shift it worked exactly as expected. Now it can sit a few weeks and it hasn’t returned.

 

[imp]

Has it been sitting? My Mounty sat mostly unused for the last few years as a second car and a 4 person golf outing car, and it would refuse to shift into 3rd under power for the first 2-3 shift of the day. It did this for a few weeks and went away. I figure something must have worked at way out.

Fluid was clean, and after the first time it did the 2-3 shift it worked exactly as expected. Now it can sit a few weeks and it hasn’t returned.

@Mbrooks420
Thanks for responding. Yes, the truck sits occasionally for several weeks. However, consider that it is hot here all the time, and nothing ever congeals except my brain. im[p

 

[Mbrooks420]

My truck came from the desert.

 

[imp]

My truck came from the desert.

@Mbrooks420
Thanks. Was it the same trans? Not aware of E4OD used in your vehicle, but WTH, many aspects are common to all. imp

 

[Mbrooks420]

Naw, truck is the a 4r70w

 

[transman304]

First place I would look would be speed sensor on top of the differential. They like to collect metal shavings and will give improper readings. Being the early model the MLPS switch has been updated over the years and maybe needs replaced. Also TPS will give same symptoms. Really hard to get proper live data readings on the OBD1 with some scanners. Is the OD light flashing? I will look to see if 4th may get inhibited by something like a knock sensor or coolant temp. Been along time since I’ve diagnosed one that old.

 

[boominXplorer]

Isn't there vacuum hoses on the back of the intake that run to the transmission for the kick down and o/d control? It's been awhile since I've seen one also.

 

[transman304]

Isn't there vacuum hoses on the back of the intake that run to the transmission for the kick down and o/d control? It's been awhile since I've seen one also.

No vacuum on this transmission. Fully electronic.

 

[CDW6212R]

If the suggested ideas don't turn up anything, and new fluid/filter is next, then it's likely a good time to consider a VB kit, plus any available solenoids, accumulators, and Sonnax VB upgrades. Almost all auto trans problems start from basic items as mentioned, or the control items I mentioned. All of them can be addressed without a shop or dropping the trans. The parts also don't take away from any future rebuild, the costs are part of a rebuild except for the VB items. Most shops won't do anything with a VB except a basic cleaning, they are afraid of aftermarket parts(unless they have heard about them countless times, then they finally adopt some things).

I've never had an E4OD apart myself, but seen them apart a couple of times. That was the king four speed in its day, very strong, and basically normal shift control items are the weakest links.