INFO: Reverse "slipping" on Ford Explorer

I've had a problem with reverse (automatic trans) on my 1999 Ford
Explorer Sport for some time. It would work fine at low throttle but
it would act like I was hold the break down if I needed more power
(like backing up a hill). I searched the internet and it really
sounded like it might be some kind of clutch problem...like reverse
and 1st engaging together. This is really the only possible problem I
could find based on the symptoms. I kept driving it without repair
for quite a while because of my assumption of a very costly repair. I
just wanted to post this info because I couldn't find any good info on
this problem and I just got it fixed. It turned out to be some kind
of servo spring. The guy only charged $82 dollars to fix. I am
hoping that in posting this it will help someone else out because it
seems to be a common problem with this vehicle but their really were
no answers that sounded as simple as a spring replacement and $82.

Hope this helps someone,
Greg