Fluid changes

[OneShotBandit]

I think we've been though this before, but I'll ask one
mo' time? My X has 55,000 mi ('98) & I want to change
Ft Diff, TC, Trans & Rr Diff fluids w/ Synthetics. My
mechanic says that this isn't necessary. I don't have
access at the Apt., should I just go against my mechanics advice & tell him "just do it" in that will start
some bad blood btw us? They (the reair shop) have a
very good reputation, I don't want to go back to my
local smilin' Ford Quality One mechanic! Thanks for any
advice. Also I've read that maybe the milage is too high to use synthetic oils/fluids.

 

[aldive]

Its YOUR truck, if you want snynthetics ( and I highly\y recommend then ), then have the synthetics put in.

If the mechanic doesn't want to do it, go elsewhere.

 

[Jason_25]

You only have 55K miles. Your mileage isn't "too high" to do anything.

 

[mrboyle]

If you want to go with synthetics, just have him do it. If he is anything like myself, he most likely doesn't belive synthetics are necessary and their cost far out weighs any benifit they may provide. I doubt you will start any"bad blood" between you and him, if it does, he may not be the best mechanic to go to after all.

 

[aldive]

If he is any kind of businessman, he will realize that the customer is right ( even if he doesn't believe in the product ).

 

[james t]

i always hear the myth "if you go to synthetics in a high milage engine/tranny, you're asking for trouble." all this talk, but does anyone have proof? does ANYONE know a person that has grenaded a 100k mile tranny BECAUSE they went with synth? what about engines? has a lab done a study on a 4 liter with the rod hanging out of the side of the block and concluded "must have been the synthetic motor oil." someone show me proof that synth. damages high mileage cars and i'll go drain the mobil 1/trick shift synth out of my rig right now.

 

[aldive]

I have used synthetic oil in motors with up to 350k miles with narry a problem nor leak.

 

[jonny 5]

I'll be switching over completely to synthetics at my 50,000 tune-up. I have a few friends with high mileage cars and syns never caused them any problems

 

[james t]

my point exactly. you always hear the "dont do it, its bad." but you never seem to hear of an actual case when someone damaged an old engine/tranny when they went to synthetic.

 

[jonny 5]

Well, while we're on the subject, I believe the front and rear diffs have ratings. The Mobil1 gear oil is 75W140, my question is can I use it in both diffs?