won't shift from 1-2 w/o letting off the gas

[medic1]

Hi, I have a 95 XLT 4.0 automatic with 220,000 miles on it. I take very good care of my vehicles and do all services regularly. the other day I was leaving work and the tranny didn't shift from 1-2 until I took my foot off the gas pedal, every other gear shifts normaly and it does not slip. I know it is electronicly controlled and there is a sensor or something on the outside of the tranny, does anyone know if that could be my problem? and if so what is the sensor called, and is it an expensive fix? Any help here would be greatly appreciated. Thanks in advance. One other thing, the OD light constantly flashes which started the same time as the shift problem, I tried resetting the codes by disconnecting the battery cable for a while, but it's still the same.

Dave

 

[Glacier991]

In the old A4LD (which you don't have) the 1-2 shift was handled by a governor. In fact the only true shift that was handled by a solenoid thru the computer was the 3-4 shift. With the advent of the 4R55E (and 4R44E) all shifting was handled electronically.
The innards of the valve body, valves that moved in response to changes in pressure of fluid routed to them, remained more or less the same.

Hence, your problem COULD (emphasize could) be related to bad computer signals (low prob IMHO), a bad 1-2 shift solenoid or one that is sticking (more likely IMHO) are something in the valve body - a sticky valve in that 1-2 shift circuit (more likely IMHO - given your mileage).

When is the last time you changed your fluid? You might have it checked to see if it is throwing any codes.

If you are planning to do the work yourself, I might suggest one course of action, if you are paying a shop, another. Is it a daily driver?

 

[medic1]

Yeah, I drive it daily, I changed the fluid and filter approx 10K miles ago and it is starting to look a little burnt. Where is the 1-2 shift solenoid located? And if it's in the valve body I'll end up bringing it to a sevice center.

 

[Glacier991]

Sounds to me like this then may be one to take in to have the valve body looked at... at that many miles they may caution against spending a lot of bucks.... that's an OLD trannie... served you well. Yet... a valve body rebuild could extend it's life even more.. it's just that the cost of paying someone to do that versus a reman is starting to be a fair question for an old trannie... which is why I asked if you might DIY.

Make sure they run it for codes....

 

[medic1]

Thanks, I appreciate the help.

 

[jayreb250]

that is exactly how my problems started I had a broken band and stuck valves in the valvebody and I don't know what else its still not working please let us know if you get yours fixed and what fixed it.

 

[SlntSam]

Was this problem resolved? Is this a common thing?

 

[Brain]

SlntSam, the "sticky/dirty" govenor has been a common thing for older A4LD's ('91-'94 vintage X's), but the OD light blinking means that there is a code ready to be read from the computer on the 4R55E/5R55E. Between that and the burnt fluid, I'm suspecting that what happened is that the computer was sensing "incorrect gear ratio", which means that somthing was slipping. When something slips it creates more heat and then starts to burn the fluid (like riding the brakes will smoke them). My deep suspicion would be that 2nd gear was not applying properly (which in this case meant that the intermediate band was probably slipping/burning), so the shift was actually either a fully applied first gear to a lightly applied (because of the slipping) second gear, or a first gear to third gear shift.

At 220K miles, I wouldn't be surprised if the tranny needed a new intermediate band (in which case the whole thing should have at least a "soft" rebuild of all the clutch packs and bands).

 

[SlntSam]

Thanks for the clear answer. I'm going to have someone clean up the govenor and replace the tranny fluid and I hope the problem I'm having will be fixed. I'm not getting any trouble codes from what I've seen.

Thanks again!