Want to flush Transmission w/high miles. Good Idea?

[PuroPinchePedo]

I just bought a 2009 Tahoe LT 2wd w/120k miles. I was going to take it this week to get a oil change and figured to flush the trans while I'm at it. I've been reading a lot of people that think a trans flush, at this point with these miles, may cause more harm than good. I have no idea of the previous maintenance. Any insight you guys have about this would be appreciated! Thanks!

 

[08HoeCD]

Shops will say it's generally safe. Most on here say not to do it, do a drain & fill instead. Hard to know how much is fact vs fiction/myth.

 

[TheAutumnWind]

pan drop, filter, drain and fill definitely ok

Forced flush is probably ok, but I'd feel better about a couple of drain and fills instead.

Anyone saying to never change it IMHO is just holding on to superstition. There is no factual argument there.

 

[MichaelSE]

120k isn't what I'd call high, but I still wouldn't do a machine flush on it. I wouldn't even do one on a brand new vehicle. If you use this method, it uses your Tahoe's own transmission pump to get the old fluid out, and there is no risk of anything going wrong unless you let it run too long and let the pump dry up.

 

[Meccanoble]

These guys know what they are talking about. Just go down the list of threads and you will see many of us recently changed our fluids successfully including me at 125k miles.

 

[PuroPinchePedo]

These guys know what they are talking about. Just go down the list of threads and you will see many of us recently changed our fluids successfully including me at 125k miles.

You just did a drain and fill or a flush?

 

[Meccanoble]

Drain and fill by myself. If you look on the second or 3rd page of this section, you will see the discussion.

 

[ta07hoe]

Is it stock or lifted? Depends on the condition the trans is in. How's the fluid look and smell and how's the truck look overall. If it looks like it was used by day laborers it's probably been beaten on. If it was a soccer moms then she might have been easy on it. If it's dark and burnt smelling I wouldn't do more than a filter and refill. Atf is a detergent, if the trans is towards the end of its life then your going to get to the end of its life very quickly by flushing it. If it has been serviced regularly then you will be alright. If and when I buy a new truck/car I'd do drain and fills ever 20k to keep it consistent. Just bought mine with 160k on it and I can't decide if I want to do the filter and refill. I probably won't and I'll just put a trans in it if I still own it whenever it goes.

And just remember people on forums don't always know why they are taking about. Do you know anyone in the automotive field or that does trans work. I'm a master tech and 2 of my friends build trans's for a living and none of us know the real answer to this question lol. It really comes down to how much wear it has on it, but that's hard to tell without opening it up.

 

[PuroPinchePedo]

Is it stock or lifted? Depends on the condition the trans is in. How's the fluid look and smell and how's the truck look overall. If it looks like it was used by day laborers it's probably been beaten on. If it was a soccer moms then she might have been easy on it. If it's dark and burnt smelling I wouldn't do more than a filter and refill. Atf is a detergent, if the trans is towards the end of its life then your going to get to the end of its life very quickly by flushing it. If it has been serviced regularly then you will be alright. If and when I buy a new truck/car I'd do drain and fills ever 20k to keep it consistent. Just bought mine with 160k on it and I can't decide if I want to do the filter and refill. I probably won't and I'll just put a trans in it if I still own it whenever it goes.

It was definitely baby'd. Still had the plastic on the front and rear radio head units. Leather is in amazing condition and body is a 9/10 body and paint. I think I'll just stick to a drain, filter and fill.

 

[ta07hoe]

It was definitely baby'd. Still had the plastic on the front and rear radio head units. Leather is in amazing condition and body is a 9/10 body and paint. I think I'll just stick to a drain, filter and fill.

That would probably be fine. Do you plan to tow with it or anything. Heat is really what kills the trans. Mines been very well taken care of that's why I'm on the fence about it. what trans do you have, 6 speed or 4 speed. My friend is a world class gm tech and he said 07 6 speeds are the ones to watch out for otherwise they are all pretty reliable.