Transmission fluid change Q

[Godgunsrocknroller]

I wanted to change my tranny fluid in my th350 because my trans shifts hard and the fluid is brownish and smells like burnt cinnamon. I have no idea how many miles are on the trans. The problem is that my auto mechanics teacher who is an ASE certified master mechanic said that if you don't change the fluid every 30,000 miles and just decide to change it for the first time at, say, 100,000 that it will affect the transmission in a bad way and it might not run the same again. Should I be concerned about this?

[1976Scottsdale]

If it needs changed, change it.  If it smells burnt, change it before you ruin the tranny.  I had to do it too.  Mine had sludge and turtle shell looking shavings in it in one of my trucks and it still did fine.  If you don't change it, you are only asking for trouble.

[Blazin]

I have known people that changed their trans fluid for the first time on a used rig with tons of miles and within days the transmision craped out. Have also seen them do it and have no problems.

[Godgunsrocknroller]

So I guess I'm screwed if I do, screwed if I don't eh?  

[VileZambonie]

Basically if that's going to happen it's going to happen anyway so just change the fluid and filter.

[82gmc3/4ton]

I would run it until it goes. The detergents in the new fluid will start cleaning the inside of the transmission. Once that starts old shavings and gunk will get into everything, clutches, and bands. Everything that was laying dormant for years will break loose and destroy your trans. Save the money and time and invest in another transmission or a rebuild kit and converter for the transmission you have. Keep in mind that you should also put in new cooling lines and either flush out your radiator or get a really good trans-cooler. My life lesson: my teacher told me the same thing....guess what happened?

[VileZambonie]

This post is 3 years old.

[SUX2BU99]

Well then with 3 more years of use, I wonder how the trans held up