I have a 2001 4WD Expy with 159000 miles. The transmission was replaced with a Ford reman unit at 125000miles. Today when I was backing my 6500# travel trailer into my driveway, I had a brief moment of panic when the transmission wouldn't shift into reverse. My driveway is uphill for about ten feet, and I have to get the engine to around 2000rpm to get the trailer up the hill. I got the trailer about halfway up the driveway, and then shifted into Drive so I could pull forward and straighten things up a bit. When I shifted into Reverse to back up the driveway again, the transmission just went to neutral. I gave it gas and nothing. I then stopped the truck and shifted to park then back to reverse and everything worked normally. What could have caused this. I think this may have happened one other time under the exact same conditions, but other than that I have had absolutely no problems with the transmission. The fluid level is fine, and is not burnt at all. I did a full flush and replaced the filter about 5000 miles ago (30000 mile service interval). I am mildly concerned since this is my primary tow vehicle and I have several long distance camping trips coming up this year.

 

Are you certain that your shifter cable is in good condition with no slack? How about fluid level? I know these seem like simplistic items,but sometimes it's the simplest things we overlook.
JL

 

I drove the truck to the gas station about 20 minutes after this episode and checked the fluid level. It was right in the middle of the hot range. I have no idea how the cable slack is. The indicator needle doesn't line up perfectly over the letters, but it's close. How do I check or adjust the slack?

 

The easiest way is with 2 people.
Have someone in the vehicle move the lever to each gear's position while you check the actual lever on the side of the trans to make sure it's stopping at the correct location.
DO NOT do this with the engine running.Seems kinda obvious since you're gonna be under the vehicle...but you'd be surprised at how many people would do just that.
JL

 

I think Johnny is right on the money. The only other thing I could think of was low on fluid or a bad o-ring on the pick up.

 

I know this is unrelated but I am curious, why did the original transmission fail? I have 177k on my '99 4x4 Expy with the original untouched 4R100 and it still shifts like new. I use it as a daily and to tow my race car around.

Shane