2003 Explorer transmission slipping

[oshp367]

My 2003 Explorer 4wd has 170,000 and has developed a slip when climbinh steep hills. It is just a slight, intermittent slip that goes away when you accelerate hard. It also goes away if you switch from 4wheel auto to 4wheel high. I assumed it is a transmission problem, but why doesn't it occur in 4wheel high? The rear end was redone about 30,000 miles back but I haven;t had any work done on the tranny or transfer case.

FYI - It started this slip about 18 months ago so I had the trans filter and fluid changed. That solved the problem until a few months ago when the slip came back. Any ideas?

Chuck

 

[imp]

How do you know it is "slipping"? Does the tachometer indicate the engine speed is "running away"? If so, how can hard acceleration as you put it stop it? Are you certain the transmission is not simply unlocking the torque converter clutch, allowing eng. rpms to increase, thereby giving the illusion of "slipping"?

Check for DTCs (trouble codes).

imp

 

[DAT05EXPLODER]

18 months is enough time to rack up some miles. I would change the fluid and filter again.

 

[oshp367]

Trans slip

You have a good point, and I will try to watch the tach next time to see if it changes at all during the slip.

I can best describe it as a shudder that occurs multiple times, maybe every second or so. I can cause it to occur by driving to the base of a hill at 50 MPH or so and then as I start climbing the hill and slowing I apply light acceleration. That usually causes the pulsations to start, every few seconds at odd intervals, as though the transmission is slipping momentarily over and over. At first I thought it was only in OD but it also occurs when I have the OD lock out on. Hard acceleration drops it into 2nd and I usually stop feeling the slip. Oddly enough, putting it into 4wheel High also causes it to stop completely.

It did stop totally for almost a year when I changed the trans fluid and filter at a local oil change center. I assume they only drained the pan and it was not a full flush of the system. I have likely put on 20k miles since then.

I plan to have the fluid changed again, and will look for someone who can do a full flush this time. I have looked at anti-shudder additives but there seems to be as many bad reviews as good ones.

 

[pet575]

Have you verified that this is not a misfire in a cylinder? Are you getting a Service Engine Soon/Check Engine Soon light or any flashing warning lights to where it might be throwing a code that you could have scanned?

I've had cylinder misfires without lights flashing that have felt similar at similar speeds. Hard accel to upshift always made it go away. Point I'm trying to make is that it might not be a tranny issue at all.

 

[oshp367]

Transmission slip?

No check engine lights, no indicators flashing, etc.

I hear what you are saying about a misfire, but would that still make sense if it went away completely for many months right after a trans fluid change? And why would it only occur in 4wheel Auto and not when you shift to 4wheel high?

 

[pet575]

That is a good point but I guess my whole point is asking if you can verify that this is the exact same problem or if it just seems like it? You may very well be right-I'm just presenting you with an alternative cause.

As to the difference in 4X4 modes, perhaps there is more load on the engine in High so that it is similar to accellerating a bit? I don't know-again, just throwing other options out there.

 

[oshp367]

Trans Slip

I appreciate the alternate ideas...I learned that lesson when I had an old Chevy S-10 with what I thought was a sticking choke on the carb. When I finally learned that the cause was the alternator, I realized I was fixated on it being a carb problem and never considered low voltage would cause the choke coil to unwind and set the choke back on....live and learn.

I plan to change the fluid first, then grab some plugs and wires afterwards just to make sure.

 

[oshp367]

Update on problem...

I replaced the plugs and wires a few days ago. The plugs (hard to admit) were original with 172,000 miles on them. The gap was over .080...far more than the suggested .052 - .054. 100 miles of driving and no "slip" felt at all. The plugs appear to have been the problem.

HOWEVER....now I suddenly have a MIL light come on P0430 that may be related to a clogged CAT converter among other things. The truck is running fine, idles nicely and runs great at 75 MPH....I wonder if the plug/wire replacement is rtelated or if this is just a new problem?

 

[RyanMc]

There is a thread that I read yesterday (as I'm new here) that mentioned this exact issue and how the OP replaced the plugs and wires and it solved the problem. I have the same issue on an '02. I feels like a "bump" or shutter around 40-50 MPH. Also, like the OP of that thread, when I first start out, the engine acts like it wants to bog down a bit before taking off.

I will be replacing plugs and wires this weekend.

I'm happy to read a follow up post on the same issue/fix. Thanks!


Here is a link to the original post, read the second contribution from "Ken":

http://www.explorerforum.com/Singleton/web/pages/plugs.html

 

[oshp367]

Update...

The vehicle (176.000 miles) runs fine with only the slightest hint of an engine miss. The shudder at 50 -60 MPH under slight acceleration is back, just as bad as ever. I still have the P0430 CEL code. SeaFoamed and no change. My next step is to do the trans fluid/filter again. I found some other posts where owners had the same shudder and found that changing the trans fluid every 20,000 miles kept the Explorer operating normally. Perhaps that offsets a possible problem with a faulty torque converter?

 

[cross6]

Update...

The vehicle (176.000 miles) runs fine with only the slightest hint of an engine miss. The shudder at 50 -60 MPH under slight acceleration is back, just as bad as ever. I still have the P0430 CEL code. SeaFoamed and no change. My next step is to do the trans fluid/filter again. I found some other posts where owners had the same shudder and found that changing the trans fluid every 20,000 miles kept the Explorer operating normally. Perhaps that offsets a possible problem with a faulty torque converter?

Add some Lubeguard in the red Bottle. You can get it at O'Reilly. It's not snake oil, a Ford TSB actually recommends it.

At worst you're out 10-15 bucks.

http://www.amazon.com/Lubegard-6090...TF8&qid=1362533448&sr=8-1&keywords=lube+guard