Transmission drain/fill at 175,000 miles?

[RayneStorm]

I just bought a 2015 Expedition xlt with 175,000 miles and wanted to start fresh with all new fluids. My local shop said they would not touch the transmission unless it has been drained/filled in the past. They expect me to keep driving on the old fluid.

Is this a thing, where if the fluid possibly wasn’t changed in the past, the new fluid now will now make the transmission inoperable, as this shop suggests? Or do I need to find a new shop?

Normally I do all my own wrenching, but it’s winter and I’m not crawling under my truck now. We are taking a family trip to Disney in 2 weeks, so that why I asked the shop to do it. Had it been summer, I would have done it myself already, because I have never heard of new fluid screwing up a transmission before.

So, is that a myth or should I be concerned?

 

[Big_O]

That’s something I’ve also heard in the past. The fluid breaks down over time and stuff starts breaking down inside the tranny. If fluid has never been replacing the new fresh fluid will flush away any “grit” and cause slipping issues.

 

[ManUpOrShutUp]

You'll get varying answers on this one. My transmission guy says there's a risk of killing the trans if you flush and fill on a high mileage trans, so we have avoided that, especially after my wife's Mazda was killed by a flush. Instead, the trans guy advises that the filter is changed and any drained fluid is replaced with new. I've never had any problems following that advice, even on high mileage vehicles.

 

[sjwelds]

Would not do a flush, but a drain and fill with filter change.

 

[Yupster Dog]

So, is that a myth or should I be concerned?

It all depends on what your transmission fluid looks like now.
Here is a video to explain,

Can Changing your Transmission Fluid Cause Damage?

Changing your automatic transmission fluid can leave you with many questions like: how do you check your transmission fluid, when should you change transmiss...

www.youtube.com

Bottom line if your transmission fluid is dark, your transmission already needs to be rebuilt and you are riding on borrowed time.
Granted borrowed time could be years, but it also could be tomorrow that it leaves you stranded.

 

[RayneStorm]

I’ll check out the fluid this week.

I was doing a drain and fill with new filter. I wouldn’t do a flush.

Thanks

 

[AnarchyOutlaw]

It all depends on what your transmission fluid looks like now.
Here is a video to explain,

Can Changing your Transmission Fluid Cause Damage?

Changing your automatic transmission fluid can leave you with many questions like: how do you check your transmission fluid, when should you change transmiss...

www.youtube.com

Bottom line if your transmission fluid is dark, your transmission already needs to be rebuilt and you are riding on borrowed time.
Granted borrowed time could be years, but it also could be tomorrow that it leaves you stranded.

This clip answered a lot of the questions I had about this topic. I've had it happen where I bought a used car with high mileage and changed the transmission filter and fluid, only to have the transmission completely crap out right afterward. Now I understand why.

 

[Trainmaster]

The older organic fluid broke down to varnish, coated the clutches, making them slip. The varnish also sealed up leaks in old organic seals. Then changing to new fluid, the highly detergent nature of the stuff opened up the seals and you had leaks. That's why, in the old days, a transmission with degraded fluid wasn't serviced.

Today, synthetic fluid resists breaking down, turning to varnish and burning. Seals are much better and last longer. Usually changing old fluid presents no problems today.

 

[BravoAlpha]

20 year old Excursion
15 year old Land Cruiser
15 year old F150
16 year old VW

I never flushed, filled, or serviced the transmissions on ANY of these vehicles.

if there are no problems and fluid color is good….leave it be.

this is based on my experience. I dont tow much and i don’t have these vehicles in harsh conditions.

 

[Trainmaster]

My '08 Expedition with 120,000 took an uncomfortable five seconds to shift into drive after sitting overnight. The delay vanished after changing the fluid and filter.