1999 Ford Explorer shifts out of gear going uphill...

[kittenofd00m]

Just outside my driveway the hill goes up a slight incline of about 20 degrees or so. I usually stop right outside my driveway with the Explorer pointing uphill, still in drive, foot on brake while I get the mail from our mailbox (this can take a minute or so if I stop to open something).

Then, when I take my foot off the brake and start to pull away from the mailbox, sometimes she goes about 10 feet and then the transmission completely stops pulling. Its like it was shifted into neutral.

I hit the brake and try shifting into a lower gear and sometimes it goes into low and other times nothing happens. When nothing happes in low, I shift into neutral and then back into drive and nothing happens - still acts like it is in neutral. To get her to move forward (while stopped with foot on the brake) shift into reverse, which catches almost immediately and then stop and shift into drive to continue uphill. Occasionally I have had to shift it into park and then reverse before it will go back into drive and continue up the hill.

I have also noticed what seems like small downshifts while driving along at highway speeds. It is very small - not like hitting passing gear. The RPMs usually go up by 200 RPM or so and then is switches right back and the RPM drops back to normal.

Has anyone else experienced this?

 

[rasouth]

Is your truck a 4 wheel drive? If so try putting it in 4WD and see if the front wheels turn. If they do then the problem may be in your transfer case.

 

[BrooklynBay]

Check the fluid level in the transmission.

 

[Mbrooks420]

Transfer case is straight through to the rear drive. It shouldn’t effect this issue. Sounds like your transmission is slipping. Your OD light ever flash?

 

[Runnin'OnEmpty]

Check the fluid level in the transmission.

Very first thing to check. Make sure it's not overfilled, since that can cause frothing of the
ATF and cause slipping...

 

[974X4BLACKSPORT]

First and foremost above all else, check the fluid level in the transmission if that is possible, I know some newer vehicles only have a fill bung in the bottom of the trans. pan. Make sure the fluid level is correct and that the fluid is not too much brown, or black, red or reddish brown is normal, very brown is bad, black fluid is rebuild time.

 

[Eric Tang]

Low fluid, check cooler lines under radiator support. Common to leak there. Find and fix leak, fill the trans, problem solved.

 

[kittenofd00m]

Is your truck a 4 wheel drive? If so try putting it in 4WD and see if the front wheels turn. If they do then the problem may be in your transfer case.

It is 2WD.

 

[kittenofd00m]

Check the fluid level in the transmission.

The level is slightly high, but only slightly.

 

[kittenofd00m]

Transfer case is straight through to the rear drive. It shouldn’t effect this issue. Sounds like your transmission is slipping. Your OD light ever flash?

No. OD seems to be working fine.

 

[kittenofd00m]

Very first thing to check. Make sure it's not overfilled, since that can cause frothing of the
ATF and cause slipping...

I thought about that, but wouldn't frothing cause some bubbles on the dipstick? And this happens within 2 or 3 minutes of cranking. Is that enough time for frothing?

And, it was doing this when it was slightly low in transmission fluid. I added some - slightly over the full mark.

 

[kittenofd00m]

Low fluid, check cooler lines under radiator support. Common to leak there. Find and fix leak, fill the trans, problem solved.

Transmission fluid is slightly high.

 

[C420sailor]

Almost sounds like torque converter drainback...but that shouldn’t happen with the engine running

 

[kittenofd00m]

Considering trying a transmission fluid replacement like you can see here - (not a flush exactly) and adding some Lucas Transmission Fix. I found an old transmission for $699 (shipping included) that has 84k on it, but the engine has 312k on it, so I am not sure it is worth trying to save.

 

[Mbrooks420]

To me it mostly depends on the body, and frame rust. Everything else can be swapped out a piece at a time.

 

[C420sailor]

Many ways to skin that cat. The way he did it is fine. You can also just pull the hoses off the aux cooler, if you have one.

I don’t run my pump dry. I pump out about 4-5 quarts, shut the truck down, add 4-5, repeat until the fluid coming out looks good. I do it every 30-50k.

 

[Mbrooks420]

I agree with above to not let your pump ever run dry. I had a graduated bucket and tried to add it as it came out, but the pump will outdo your funnel every time.