Hi Lone Wolf.
I have a 2004 SportTrac with 346,000 km on it (212,400 miles). This is in minus 40 degree winters and 95 degree summers. All easy highway miles. An easy life for any vehicle.
Oil changed every 5000 km (3000 miles). No timing chain rattles (thankfully), transmission oil and filter never changed until I bought it from my brother in law two years ago. Rear diff oil never changed until I bought it two years ago. Runs great. Spark plugs and wires never changed since new. The new plugs and wires going in next week.
I would have no worries whatsoever about towing an only 3500 lb trailer. Well within the towing limitations.
Might require a rear leaf spring "helper" if there is too much sag with the current leaf springs. I replaced the rear leaf spring bushings last year...what a tough job that was. Had to loan a tool from PartSource ball joint tool and "invent" a bushing puller out of 1/2 inch threaded rod and some large washers and pipe. Ford puts these bushings in with a ten ton press in a factory..not a job for the average back yard mechanic...I have much experience working on cars. Trucks. Tractors.....etc.
The bushings were so worn out basically I was driving on the bolts. The bushings were completely gone. You may want to do a very careful inspection of the rear bushings on the rear leaf springs before attempting to tow a trailer. Ford is the only place that I could find where you can get these...they are about $90 bucks each. A major PITA (pain in the ass) to replace. But doable. After replacing those bushings, new front upper control arms, new front lower control arm bushings. new ball joints, new shocks front and rear, my truck handles like a sports car.
If the rear differential gear oil has not been serviced when it is supposed to be...it might be a good idea to drain that old gear oil out (which will require taking off the rear differential cover) and putting in the Ford recommended gear oil. Clean out all of the gunk on the bottom of the diff housing with your fingers. My brother in law has not ever had the rear diff oil changed...after that many miles....my truck thanked me for doing so.
Also perhaps consider a transmission filter change if not done within the last 80,000 miles. A few liters (quarts) out of the twelve or so liters in total for the system to replace whatever transmission oil is required when you change the filter. Don`t worry too much about changing out ALL of the transmission oil. The transmission pan gasket and oil filter will cost about $25 bucks. This is in Canada...you can probably get it for far less in the US.
After much research into the matter...having a transmission "flush" is not recommended. This only loosens up all the gunk in the system to plug up all the small passageways in the trans to cause future problems. Just replace whatever is necessary when the trans filter is replaced.
A new rear diff gasket cost me about ten bucks...can`t remember what the gear oil cost.....maybe about fifteen bucks. A good and reasonably inexpensive insurance policy before towing a reasonably lightweight trailer.
And also the engine oil...use the Ford recommended oil and filter (there is no better filter available than the one from Ford...I have done much research into this matter)...my local Ford dealership sells the oil and the filter for $28 bucks. Fram filters are about the worst thing. Don`t use synthetic engine oil...the timing chains and cassettes don`t like this kind of oil. It is too thin and drains back into the oil pan and takes too long to pump up into the chains on cold starts...especially in very cold climates.
I had similar concerns regarding the timing chains and was going to replace the tensioners. Just because of the high mileage.
The local Ford parts counter guy I have been dealing with for years told me not to do that. The new tensioners may put too much pressure on those old and worn timing chain cassettes (a very big problem for the 4.0 SOHC before late 2003) before they redesigned them with new plastic material.
If it ain`t broke don`t fix it. Don`t go looking for problems and try to fix them when there are none there. The Ford Explorer SportTrac is an awesome truck. The model years of 2001 to 2005 are selling in my area for $4000 to $7000 with over 200,000 km. Not sure what they are selling for in your area....it is a desireable truck...four wheel drive...small and easy to park...very good in deep snow....capable of towing a small trailer.
You may want to carefully inspect the rear bumper assembly and how things get hooked up with the bumper towing ball. Maybe beef that up a bit if you are going to be driving over big steep hills, rough roads, etc.
Unless you have lots of money to burn, don`t sell your SportTrac. If you are considering something else as an upgrade...the F150 is the way to go.
The EchoBoost engine is a POS. The Triton is a POS. (piece of s_ _ t). The only engine for any Ford truck, old or new, is the 5.0 L 302 V8.. It has always been and will continue to be the best engine that Ford has ever built. I am researching and searching for a 5.0L to swap into my SportTrac when my current 4.0 L dies. That may be in another 100,000 miles or so. Who knows?
Hope this commentary helps you out. Let me know how things go with your towing plans.
