2000 ford explorer tran slip!!!

Hey everyone!!!
I got a 2000 ford explorer with 151k on it...
Since iv had the truck (5yrs) its always had a slight slip around 3rd going to 4th.
The tran is auto!!
I use to be able to jump in and take off but here lately i have to let the truck idl for a few sec or up to a min before i can take off (warm or cold)
This just started a mth ago...
The tran fuild smells burned and it has be 2yrs since iv changed fluid and filter in the tran...Everything other then that iv kept up to par.
What do you think should i start looking for something new or just change filter and fluid????

I know the truck has had a good life sooo im starting to think the tran maybe trying to go....
My friend has a 85 dodge ram charger suv not sure the miles but its auto as well....It has a 318.
other then a small dent the thing look good...
It has some kinda vacuum leak major but doesn't effect running {wierd}
He told me the leak is from something he had removed when we left CA that they said he had to have for smog????Any ideas???

Would this be worth the trade????

witch truck would be cheaper to repair/replace part on???

what would you do??? keep in mind i dont have alote of cash...

Give me pros and cons...

Thanks God bless!!!

i have a 2000 ford explorer xls 6 cyl 4.0 litre johnny bauer edition . I have the exact same problem with third geer slipping i was referred to a tranny specialist and he told me i had only two options to rebuild the whole tranny or just replace third geer to rebuild the whole tranny it would cost me around 5 grand with a full warranty package , and to replace third geer he quated me about 1500-2000 dollars without any warranty. if this is out of your budget another option would be to contact scrap yards in your area to see if they have a good third gear at a lower cost and find someone with the know how to install it. im just curious does your overdrive light come on when your driving the truck because mine does.if you have a solution to this please let me know. And does you abs light come on. I recently had a tranny flush and noticed a huge difference in acceleration and fuel economy it would be wise to get one done.
check out a few things the suspensions on these trucks are very poor and dangerous i just looked into a few good products at a reasonable price the first is 4 WHEEL AIR SUSPENSION CONVERSION KIT BY STRUTMASTERS 18665972733 MUCH SAFER BETTER HANDLING AND WILL SAVE YOU MONEY IN THE FUTURE FOR COSTLY SUSPENSION REPAIRS PRODUCT CODE FOR OUR TRUCK IS XPL-4 WITH LIFETIME WARRANTY. ALSO LOOK INTO ACTIVE SUSPENSION KIT CODE FOR FORD EXPLORER IS RM-MK3-XEB-3526-1. 2 YEAR WARRANTY THESE TWO PRODUCTS WILL END UP SAVING YOU TIME AND MONEY IN THE LONG RUN . HOPE I HELPED YOU OUT GOOD LUCK.

I have a 2002 eddie bauer automatic and i was having the same problems and just learned to deal with it. Eventually the jerking got so bad I had to get it looked at. I had to replace the transmission coolers it cost about 700-800 and was done in a day. The car has never had the problem again and I didnt have to buy/rebuild the whole transmission.

The tran fuild smells burned

won't that mean that your clutch packs are toast & a rebuild / replacement is the only remedy?