Automatic transmission slips out of gear. Help!

[XtremExcursion01]

This just started a couple days ago on my 2001 Excursion. While driving at a steady speed, occasionally, it feels like you put the gear shift in Neutral and then the RPMs climb until I let off the throttle. After I let off for a few seconds, it will usually re-engage. Sometimes, I have to give it a few tries. It will also do this occasionally at around 25-35 mph while accelerating. The highest speed at which it slipped out of gear was around 55-60 mph, with the cruise set. (Well, I think the cruise was set, I do know that it was while I was at a steady speed and was not just after a shift. It was also in OD at the time.) Also, I noticed twice that it didn't seem like it wanted to shift into overdrive when it normally would, until I let off the throttle briefly. I checked the fluid and it's right on the money, and looks like new, not burnt at all. Again, these symptoms seem to come and go. I noticed it once at about 25 mph the day before yesterday, and many times yesterday, but today it didn't do it once. But, I didn't drive it much today. By the way, when it stays in gear, it has plenty of power from a start and all the way through the gears. Every shift is firm... when it doesn't slip out. There are no codes being thrown either. I am thinking that since the tranny is still capable of firm shifts and the fluid looks good, that this is probably a bad sensor somewhere, but where should I start? Thanks in advance for any ideas.

[straycat]

I'm afraid I can't help you on this one, but I'm sure one of the guys that can will be along shortly. Good luck with it.

Gord.

[straycat]

Just noticed it's your first post, Welcome to Powerstroke.ORG, hope you enjoy it here.

[Patrick]

If you dont have a programmer or a code reader you can have this done at Autozone or similar places. This should tell you if a sensor is bad. You may want to go ahead and have the trans flushed, and filter changed.

The 4R100 isn't the most desirable trans to ever come in a diesel truck, but with the right parts it can be. My partner Larry just did the trany in his 00 Ex, and now it shifts firm like a new torque shift trany. If you have any questions give him a call 724-462-3669. I would not suggest paying 2800 bucks to have your trany rebuilt stock.

Oh ya...Welcome to the best Powerstroke site on the net!

[XtremExcursion01]

There is an Autozone here in town that I have used to read codes for me before. There are no idiot lights lit, though. If a sensor is bad, will the code reader be able to find anything? If so, will it be able to find anything while the truck is sitting, or will we have to take it for a drive and wait for a malfunction? As far as the fluid goes, it looks great and only has 4176 miles on it. (I just went out and checked my book to see. I knew there weren't very many miles since I had it flushed.) Thanks so much for your help. I'm looking forward to the next reply(s).

P.S. You said, "I would not suggest paying 2800 bucks to have your trany rebuilt stock." I completely agree! Anything that ever breaks on my truck is not just repaired, but improved. I'm all about replacing a weak link with a stronger one. I'd just really be surprised if I need to replace or rebuild the tranny right now. Do you think it is in it's last throws of life? Man, that would stink!

[kromewldr]

sounds an awful lot like a manual lever positioning sensor (where the wires hook into the tranny) especially since it won't throw any codes, mine is doing the same thing but it throws codes. the mlps tells the tranny computer what gear its in so it can shift accordingly.... hope this helps

[XtremExcursion01]

Is the MLPS same thing as the TRS (Transmission Range Sensor)? Because I bought a new TRS, installed it, and it still slips out of gear. I haven't been driving it lately, been driving the wife's truck and letting mine sit. I'm to the point that I'm just going to find a tranny shop that will check it for me for free. With no codes being thrown, and I already tried the TRS, I don't know what else to try. I would appreciate anyone's suggestions. Thanks.

[bigcountrysg]

You may need a transmission scanner. As some codes that are thrown by the tranny, and abs are not readable by all scanner tools. You also will not get any trouble lights on your dash if these codes are thrown.

As for tranny shops I recommend

AAMCO.com - Home (Transmission Repair, Transmission Service by Aamco. Car Repairs & More)

[kromewldr]

sounds like its doing the same thing as mine, i'll find out more tomorrow, as i'm going to the ford garage to get some answers

[kromewldr]

mine ended up needing a new wiring harness (the one that leads from the trans) was pulling the truck out of lock-up, because it thought the truck was still cold, cost about $280 installed