Transmission Fluid Flush or Change?

[TheSJHL]

Hello - I am looking for advice on which transmission service is preferred. 

 

Are you guys getting your transmissions flushed or changed?  From my understanding, a flush sucks out the old fluid while filling with new fluid.  A change includes dropping the pan, draining only a portion of the fluid, installing a new filter, re-installing the pan, filling with new fluid.

 

2018 Silverado 4x4 Z71 (5.3L, 8 speed)

73,000 miles on the odometer...fluid is original and never been changed

No issues with the transmission (only "complaint" is shifting from Park to Reverse results in a "clunk")

 

Thank you!

[diyer2]

Personal choice. What makes you happy?

DIY or pay?

I would drop pan, filter refill.

[BlancoSilverado]

At min change the fluid, if you dont want to drop the exhaust, you can pick up a transfer pump from harbor freight (SKU: 63144, 66418, 3878, 61364, 63591, 62961, 63076) and pump out fluid from the fill port and then pump new fluid in.  

 

*As @diyer2 says, DIY or mechanic? always prefer to change the filter. 

Edited November 9, 2021 by BlancoSilverado
** added more info**

[TheSJHL]

I will be taking it to either the local Chevy dealership or to an independent mechanic.  The exhaust location is the reason I prefer not to DIY this one.

[Donstar]

A few weeks ago I decided to try out our local drive-through oil change shop.  During the service, the technician showed me the prematurely dark color of my transmission fluid.  I attribute this to hauling a heavy travel trailer for a couple of seasons.   I knew from my time on this forum that a change c/w filter is the preferred remedy.  However, I decided to go with the flush offered at this facility because of cost and convenience.  My transmission now has red fluid coursing threw its veins, which is the desired outcome of a flush or a change!  

[dieselfan1]

It's up to you. 

I have two 2018s 5.3 6 spd.

One is bone stock. 60,000 miles. I just flushed this one and called it a day.

The other truck is running  10.5" lift with 38" tires. 50,000 miles I did the pan drop and new filter.

Obviously the lifted truck is under more stress so cleaner the better in my book.

If you plan on keeping the truck past 150,000 miles I would drop the pan and do a new filter instead of the flush.

That's my tip of the day.

 

[Black02Silverado]

Yes, drop the pan and change the filter. 

 

Then in 30k miles just replace the fluid, then repete in 30 to 40k. 

 

You could do a fluid exchange but not really needed.

[Alan Bowman]

1 hour ago, dieselfan1 said:

It's up to you. 

I have two 2018s 5.3 6 spd.

One is bone stock. 60,000 miles. I just flushed this one and called it a day.

The other truck is running  10.5" lift with 38" tires. 50,000 miles I did the pan drop and new filter.

Obviously the lifted truck is under more stress so cleaner the better in my book.

If you plan on keeping the truck past 150,000 miles I would drop the pan and do a new filter instead of the flush.

That's my tip of the day.

 

Third time I’m writing this up.

I just did both axles, t case, dropped the trans pan and replaced the filter. Cost me about 250$ not bad I think. All new oils all around except coolant.

wanted to protect that G80.

I guess my truck is one of the lucky ones with the 4.21 gears or what ever it is. self satisfaction lol. 
 

[MikeBMW]

Just had mine done at the dealer.
Flush and fill with a filter change.
Not a big deal.

 

[Alan Bowman]

14 minutes ago, MikeBMW said:

Just had mine done at the dealer.
Flush and fill with a filter change.
Not a big deal.

 

Yeah I got the better deal hands down  250$ a little shy I did both axles, t case and the trans drip pan removed and  did the filter. All my fluids were dirty. Only at 55k miles.

[MikeBMW]

1 hour ago, Alan Bowman said:

I guess my truck is one of the lucky ones with the 4.21 gears

G80 is locker is  <s>3.73 gears</s> , I guess you are lucky ... or mistaken?
 

58 minutes ago, Alan Bowman said:

Yeah I got the better deal hands down  250$ a little shy I did both axles, t case and the trans drip pan removed and  did the filter. All my fluids were dirty. Only at 55k miles.

Better deal, but if you did even one thing wrong, you have no one to blame except yourself.

On my BMW 1990 535i, I do a lot of my own work like ECM and TCM chips, wipers, stereo (with the stock radio, gotta keep it original) etc., but, when it comes to the important stuff, i.e. engine, transmission, power steering, I still take it to my local BMW mechanic who specializes on old BMWs (heck, he adjusted my valves a second time for free because the first time wasn't perfect - 200K and still going).

BMW:
 

Edited November 10, 2021 by MikeBMW

[JimCost2014]

1 hour ago, Alan Bowman said:

Third time I’m writing this up.

I just did both axles, t case, dropped the trans pan and replaced the filter. Cost me about 250$ not bad I think. All new oils all around except coolant.

wanted to protect that G80.

I guess my truck is one of the lucky ones with the 4.21 gears or what ever it is. self satisfaction lol. 
 

Check the RPO code sticker in your glove box:

 

[MikeBMW]

46 minutes ago, JimCost2014 said:

Check the RPO code sticker in your glove box:

 

Yep, I have the G80, I have the RPO codes from Chevrolet (build sheet) and my G80 is 3.73 gears.
I have yet to find info on anything different.
Oops, see above and below ... I was way off base on this one, sorry ...

Edited November 10, 2021 by MikeBMW

[MikeBMW]

24 minutes ago, MikeBMW said:

Yep, I have the G80, I have the RPO codes from Chevrolet (build sheet) and my G80 is 3.73 gears.

Oops! Sorry, @Ravenkeeper and @Alan Bowman , I just checked my build sheet again, my G80 is 3.42 gears.
Thanks, @Ravenkeeper!
From my build sheet:
G80 - AUTO LOCKING REAR DIFFERENTIAL
GU6 - REAR AXLE 3.42 RATIO

[Alan Bowman]

9 hours ago, MikeBMW said:

Yep, I have the G80, I have the RPO codes from Chevrolet (build sheet) and my G80 is 3.73 gears.
I have yet to find info on anything different.
Oops, see above and below ... I was way off base on this one, sorry ... I wish I had the 3.73!