The SOHC 4.0 most definitly DOES have a rear cam chain and the factory manual states engine removal is necessary to service.
If it has a chain on front and on back of the engine, and the guides are worn as well as the tensioner, then it can take upwards of 12 hours to complete the repair.
Yes it can and will take 7+ hours to replace the timing chain. The radiator and radiator fan must be removed to replace it. Depending on which motor you have the A/C pump, alternator, water pump and powersteering pump must all be removed. Not fun and not easy.$500+ iscommon price for timing cahing/tensioner to be replaced.
Now, that's funny. My 1999 Explorer is at the local Ford dealer now where I was just told that BOTH timing chains had to be replaced - the front one and the back one. Oh yeah, the price tag - $2350. (I'm looking a new ride)
Seven hours is 3 hours less that the best estimate I got!I have the same scenario on my '98. $2300 estimate, including valves (assumed damaged, but I have my doubts, I drove about 30 miles after the chain skipped engine did not die until I got back down to idle). I am in the process of pulling the engine myself to get a look at what is wrong. I am believe there are actually 3 total chains (2 upper cam chains and a main, I was told my main is the one that skipped). I am in the middle of this repair (still pulling the engine) and I am having trouble finding the parts (chain and tensioners). I am also told that setting the timing is tricky so I may have to take the engine in to have it done. But the largest part of the bill is removing/installing the engine. Yes, I got a new Econoline to replace the vehicle in the mean time (needed more ROOM anyway) but I want to get this back on the road, so if anyone has any suggestions (besides the dealer) for parts I am all ears!