Hi all, long time lurker, first time poster. Apologies for a long and rambly post.

My family has had our 2000 Excursion V10 4x4 since 2001 and it's been nothing but the best for us. Unfortunately, my parents are car-illiterate and only have done regular oil changes in its 190k miles. I've just recently gotten into cars and after heavily reading this forum now realize the seriousness of our neglect. I wish I had learned about this place earlier but I can't turn back time, so now I'm trying to catch up on deferred maintenance.

Specifics of neglect:
Mainly used for hauling 8 people and cargo; only towed with it twice; 50/50 city and highway; 4x4 only used about twice a year in deep snow. We weren't exactly using it to its limits (except the seats)

Coolant has been changed once, 5000 miles ago (just a bit late), thermostat replaced at same time.

Transmission fluid never changed (yikes), fluid is dark and burnt smelling but no shifting issues whatsoever.

Diff fluid never changed (double yikes), fluid quality unknown; no issues noticed (noticed being the key word I guess).

Front brakes just replaced with rotors and fluid, rear brakes up next.

So far we have had no problems, but I'm fearful of the future and want to prevent any expensive repairs if possible. I'd like to change the tranny fluid soon, but I've seen the arguments about whether to leave old fluid in a neglected transmission. I would change the fluid but it's not my truck and if I kill the tranny I'll feel awful since my parents can't afford a tranny rebuild right now and I don't like that risk. I have similar sentiments on the diff fluid; I want to change it but I'm scared I'll do more harm than good and we can't afford a new diff. Can you guys advise me on the transmission and diff fluids? And is there other essential work we've missed over 190k I haven't mentioned? Thanks in advance!

 

If the trans fluid is burnt then replace it. If the transmission dies soon after it was not because it was suddenly supplied fresh lubrication, it was because it was neglected for 190k miles.

As for the missed maintence, bust out the owners manual and go through the maintence interval section and it will list what was recommended at various milestones. Compile a list of what was missed and there is your to do list.

 

Welcome to the forum Eagle!

Like Pirate said, clean fluid won't kill a trans. That old myth is built around people who drive the trans until it starts to develop an issue (or several issues) then they change the fluid and the trans fails soon after. The new fluid didn't do the damage, the thing was failing prior to the fluid change and new fluid, while always better than old burnt stuff will not repair damage done. Change you fluid.
Do you still have the original spark plugs? Be very careful replacing those and follow the proper procedure to avoid issues after the change. This and tons of other good info can be found in the tech Folders at the top of this forum page.
Differential fluid change is much like the trans, new fresh fluid isn't going to hurt anything, change it out with the proper synthetic fluids.

If you have more questions on these various maintenance items after reading through the Tech Folders (and Owners Manual) ask away and we will try to help answer them and help you get through the work more easily. Where are you located?

 

Welcome to the forum! Good on you for getting to the maintenance. Beware of the addiction to working on and modding these things.

Throw up some pics for us when you get a chance!

 

Welcome!
I'd change ALL fluids including transfer case and power steering. Lube front hubs, front wheel bearings. Make sure all vent lines to diffs, transfer case, etc are cleared.
You're a wise man doing this BEFORE something breaks!

 

Do these Trannys use friction clutches ?? If they do, I would not R&R the fluid. OLD myth or not, in the 70s I manged a transmission shop in Houston, we offered a $19.95 fluid change to get cars in. Saw more that one car come in with really,really burnt fluid. The only reason the car was driving was the all the GUM & VARNISH that had built up on the clutches, new fluid will clean & wash them up to the point the tranny would start slipping soon there after. One car never moved off the lift ??

 

Almost forgot: WELCOME to the world of XXXs

 

Harley, that was 40 years ago!
So you'd advise just running it until the whole trans becomes a burnt slipping ball of goo?
Might as well never change the engine oil either, 'cause it may start a seal leaking!

 

YES it was, & ALL my XXXs are 17 YEARS OLD
I do not know if these transmissions USE FRICTION CLUTCHES, but if they do I'd drive it till it stopped. THAT's ME , I did not tell the OP what to do. I would also start saving for a tranny either way. As far as I know my 6.8 does not use friction clutches So I would change the oil, no mater what it looked like.

 

We have an older fellow that used to work at a transmission shop say the same thing here at our shop. Could have easily been 40 years ago.

This reminds me, I need to drop my pan and change my transmission oil and filter here pretty soon. Might as well do a transfer case oil change while I'm at it eh?