I have a shifting or power problem with my 94 5.0 (113K miles). When I'm cruising at higher speeds (above 45?) and I come to the slightest incline, it downshifts and then upshifts constantly just to maintain speed. It's really noticeable above 60-65. This happens with the cruise control on or off, OD on or off. It seems to accelerate fine (only had truck a few months so I don't know how much power it should have). It also doesn't want to kick down to 2nd when I floor it going 55-60. Check engine light is off and no stored OBDI codes are coming up. Couldn't find any vacuum leaks, checked the TPS with a meter, the resistance is within specs and changes smoothly. Checked the EGR position feedback resistance (moved it with a vacuum pump) and it looks OK too. Disconnected the EGR vacuum while engine idles and moved EGR with the pump and engines stumbles as it should. I haven't changed the plugs yet but plan on doing it soon. Trans fluid level is OK, smells OK. I realize the tranny is electronic, but would a shift kit help me or is it an engine problem? I've also read there is a solenoid in the trans that is known for causing problems. Any ideas out there? Or should I drive it off a cliff?

 

That truck likely has the E4OD trans (check the door code and compare to the sticky in the Trans forum if unsure).

I remember hearing something that some of them had crappy settings from the factory that resulted in, well, crappy and rough shifting. They released an update, and trucks could be brought to a dealer for a free reset. Now I don't know if that's your problem, but if it's been doing this ever since you got it, maybe check that out.

 

Those $100 Transgo kit's really make a world of difference in the E4OD. There easy to install , you get quick shifts and they put a hell of allot more power to the ground. Mines like a different tranny since installing the kit..

 

RaWarrior:
Thanks for the reply. It should be a 4R70W - trans code is U and pan has 14 bolts.

 

They have a kit for that as well.

 

You could have an erratic locking torque converter. i.e., some of that shifting may be the converter locking and unlocking. The 4R70W requires Mercon V synthetic fluid - it is prone to heat problems. Otherwise, it is a good, solid, transmission. A flush n fill using the cooling lines and a vacuum pump (vice dropping the pan) may greatly improve things. A re-flash of the prom by a dealer may also help. A shift kit, as suggested by jbrew, will improve the transmission's performance if "normal" doesn't suit you. I'm just not sure if you are experiencing normal behavior, or you have a problem. In other words, be sure your transmission isn't broke before you start upgrading it.

 

Yeah , another thing that doesn't get explained to much is that the valve body consists of plastic plungers and aluminum pistons within , it doesn't take much to contaminate .

First you'll smoke the plates , then your clutch disc will get hotter thru normal operation , after time , little pieces break off here and there as it begins to deteriorate and contaminates the accumulator / valve body as it flows threw the system.

This causes erratic shifting because your plungers and pistons within the valve body begin to stick/jam - fail to function properly.

Usually people get there tranny flushed as a first attempt to cure the problem.

This works well enough the majority of the time because it washes said contaminants away and free's up the stuck stuff..

Just a valve body swap and replacing your aluminum pistons and plastic plungers with steel ones does wonders for these transmissions and is cheap . Many go thru the great expense replacing there transmissions when they just need a valve body over haul..

 

Thanks. I may do the flush & fill on her. I just had it done on my 98 Expedition and it took care of the "washboard" rumble when going in & out of lockup. Can the 94's be reflashed? I still wonder if it isn't engine/power related. I changed the plugs and checked the timing but it made no difference.

 

Thanks JBREW. I've also heard there are problems with a pressure solenoid??? This premature upshifting then downshifting is driving me nuts!

 

Can a 94 be reflashed? (I hate going to a dealer for anything!)