Hey all,

ive got a 1994 f350 5.8L with the E4OD tranny. Had it for a little less than a year now, and it’s been such a conundrum from the beginning. The thing is pretty much mint, garaged it’s whole life, and has only 90,000 miles on it. The issue is I can’t seem to figure out what seems to be an electrical problem with the transmission. It will sometimes drive perfectly fine, and stay in overdrive. Other days it will go into limp mode; shift from 1-2 and then go straight into OD. OTHER DAYS, it will shift all through the gears but won’t stay in OD. Will kick out the second I give it any gas, and slam back into OD when I take my foot of the pedal. Replaced all sensors ( VSS, TPS, MLPS) replaced solenoid pack twice, changed fluid and filter. It also has startup issues now where it won’t crank some days, other days ie will start up fine, and others it will start up and then idle real rough and then stall and die. I’m not sure if I have a bad computer that could do that, but I pinned all of them and they came back good. The only thing that remotely even seemed to fix the tranny issues with was when I bypassed the fuel inertia switch because it kept shorting out. That literally made the tranny issues go away for about 6 months, and then they came back about a month ago. I’m at a loss guys. I have no OD light flashing, and the only codes I get are a 622 (Shift solenoid 2 code) and a 512 code (keep alive memory), but I’ve had those codes when it drove fine and after swapping out the solenoid packs.

 

It sure sounds like a wiring harness problem.

 

different truck but my trucks been doing pretty okay lately. i see a lot of 1-2 harsh engagements, but i was wondering what would be potential cause of almost only a 2-1 downshift harsh engagement, all acceleraitng and other downshifts are rather fine, too.2-3, great, 3-4, usually very soft I have to feel for it if its noisy enough

I dont think its something worrysome, its not every time but Its most pronounced when trying to come to a full stop, it seems like it would like to stay in 2 until like 5mph, which if you were to accelerate before 2-1 it just goes in 2

 

The only way that I can see the 2-1 shift being harsh is if the engine speed is too high.

 

Huh.. that is interesting. I have been trying to understand it, but I do have a lean condition that the pcm will go to 25-32% fuel trim on bank two trying to compensate, but its intermittent. And i also have, as you know, a situation where slowing down, usually breaking, the truck sometimes shifts roughly into 1. and you say engine speed too high possibly.
I think im gonna pay a visit to my brake booster and check valve and hose procedures in the service data LOL

I dont think or know tbh if the lean stuff I see on the codes is related to booster or components, but the fact that they both occur without eachother very ilfrequently but often togeher makes me feel this very possibly isnt purely related, so I may very well find a vacuum issue when breaking, so fix that if so, but the lean happening without breaking ill keep in mind it still may have that issue and thereby may still occur when breaking, but hopefully a reduced amount, if im thinking in the right course.

Ive been considering possibly getting into the industry by taking advantage of the book learning ive been doing but strangely am retaining it like a sponge, and even tho the reason is sad what better way to cakewalk a course for say, tech school, right?

well i dont think iwould be a good noodle at religiously following Stratgy based diagnostics, whoops

 

I would pull the computer and look for leaking or corroded capacitors..