Is a transmission fluid flush bad?

[kcyota]

My 4Runner is in the shop today. I just bought it with 235k miles on it, so I wanted to have it checked out.

One thing the mechanic mentioned is that I should probably have the transmission fluid flushed, but he also warned that he's seen some vehicles have more transmission problems after a flush. He knew of one specific case where the fluid was horribly dirty and old, and doing a flush created lots of problems later.

Thoughts?

 

[LINY4Runner]

some people say with alot of miles on a transmission, the gunk and dirt in the fluid actually helps fill the warps and imperfections that happen to seals over time. the idea is with a flush, you clean out all the old fluid with pressurized new fluid, thus cleaning out the gunk that was helping the seals do the sealing and causing a leak.

i'm not sure if this is true or a myth, but your best bet is take a look at the fluid first, it should be a deep red color, like blood, but not as thick. if it's brown or black and somewhat watery, you might wanna just drain it out and fill it back up, which really only changes the fluid in the pan, leaving the majority of old fluid in there. this is normally done once every 30k and can be done until the end of time.

the problem is that you don't know if this regular maintenance has been done up to this point, so your best bet is to take a look at the fluid and go from there. if you are unsure, wipe the dipstick on a regular piece of white paper and take a pic and post it on here so we can all have a look-see.

It's an easy enough job to not have to pay a mechanic. Honestly it's the same as changing your oil only you dont have to drop the skid plate or change a filter, so actually it's easier.

 

[One_96TR4]

Hey I would recommend just doing a drain and fill. Yes it doesn't change all the fluid but you can do it again in a few weeks and it gets most of it out. My uncles been doing transmissions for a little over 20yrs now and he always recommends to do a drain and fill for a car with over 60k miles. The only time they do a full flush is when they have a radiator cooler burst and coolant and tranny fluid mix in an attempt to save the tranny.

 

[kcyota]

Thanks for the info guys. He did mention that it was still reddish, so he wasn't too concerned about it.

Front brake pads and rotors, radiator flush, and new spark plugs and wires today. Still need to do timing belt and shocks. Yikes!!!

I'm not too surprised since it pretty much hasn't been serviced for the last 100k miles, but it still hurts the pocketbook.

 

[SIKHILUXSURF]

wat every you do dont flush the trans on you runner. when i was at the dealer a jack ass service writer recommended one and upsold it to a customer he got fired shortly after. the flush caused damage to the trans seals and also the car had leaks andshifting problems after because of all the forced fluid that when through the trans from the power flushing.

 

[4daRUNNER]

simply drain and fill. i have been told that it is not required to flush out the transmission fluid, on any vehicle. oh, and yes, its much easier then changing your oil and filter.

 

[sseaman]

I would go the drain and fill route, since this is a new to you ride with higher miles, I would do it a couple times over the next year. i regularly drained and filled my LC and the tranny had 320k miles when I sold it with no problems.