DIY Transmission Flush

Reply

  #1  
Old 03-27-16, 07:44 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
DIY Transmission Flush

I've watched a couple videos and read a few articles about doing a transmission flush and all of them start with draining and refilling the transmission, then disconnecting the cooler line leading to the radiator, feeding it into a bucket, and pouring fresh fluid into the dipstick hole while the engine is running until fresh fluid comes out. I'm curious as to why one couldn't instead disconnect the return line and submerge it in a bucket of clean fluid and let the pump do all of the work. Start the engine and when all of the fresh fluid in the bucket has been sucked out, shut the engine off and you're done. Will this not work?
 
Sponsored Links
  #2  
Old 03-27-16, 07:59 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
I worked as a mechanic for a car dealer for 2 years & never once did we do a transmission flush. At the most we dropped the pan & changed the screen. What makes you think that you need to do that?
 
  #3  
Old 03-27-16, 10:22 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
To get all the fluid out of the torque converter. I could just drain and refill three or four separate times I suppose. I don't think the fluid has ever been changed and the truck has 145k miles. I figured it would be a good idea to replace all the fluid, not just 2 quarts. I'm suggesting letting the vehicle do all the work and just providing one drain bucket for the outlet and a bucket of fresh fluid for the inlet. Would this work or would the fluid need to be pumped back in?
 
  #4  
Old 03-27-16, 12:50 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
I don't know for a fact but I strongly suspect that the return line from the cooler simply dumps into the transmission sump and the internal oil pump simply takes suction from the sump. If I am correct the pump would remove all the oil from the sump and then stop pumping. You would get no flow through the cooler return line and could possibly cause severe internal damage to the transmission.

Now perhaps you could rig a hose to the return line that would go into the bottom of an elevated supply canister holding a quantity of transmission oil and do it that way. Or, pay the $75 at the service station to have it done. Remember, if YOU screw up the transmission the repair comes out of your pocket but if the service station screws it up they have to pay.
 
  #5  
Old 03-27-16, 04:49 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
With so many miles on it, I wouldn't touch it. You can do more harm than good. What color is the fluid?
 
  #6  
Old 03-27-16, 06:01 PM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
I don't know about the color, I was just thinking it is time it needs to be done. Are you suggesting it never needs to be done and the fluid lasts the life of the vehicle? How would a simple drain and refill harm the transmission?
 
  #7  
Old 03-27-16, 08:04 PM
Join Date: Jun 2010
Location: Canada (near The Motor City)
Posts: 617
"Are you suggesting it never needs to be done and the fluid lasts the life of the vehicle?"

We don't know !! You havenít told us yet what the heck you are working on !!

Your original post was about "flushing" .. now you're asking if a drain & fill would hurt.

My head hurts. I'm outta here.
 
  #8  
Old 03-27-16, 08:55 PM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
Well that's because my original question wasn't vehicle specific. I simply wanted to know whether the method I mentioned would work. Sounds like it won't and that's the answer I expected. One of the replies now has me questioning whether the fluid should ever need changing. I just checked my owner's manual says to change it "as necessary", whatever that means. Vehicle is a 2004 Toyota Tundra, 4.7L V8.
 
  #9  
Old 03-27-16, 09:16 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
How would a simple drain and refill harm the transmission?
People have blown transmissions if they changed the fluid when it had a brown color.
 
  #10  
Old 03-28-16, 03:31 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 44,365
I've also heard that if the fluid is changed on an old neglected transmission it can lead to problems. A tranny guy told one of my sons that the best thing to do on an old transmission that has never had the fluid changed was to change the filter and reuse the old oil. Apparently the detergents in the new oil will break up deposits in the tranny and when they circulate they tend to plug something up.
 
  #11  
Old 03-28-16, 06:24 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
Makes sense. Up until now, I thought it was supposed to be changed every 30k. I had an Infiniti G35 that had a rough downshift from 3rd to 2nd and would also remain in too low of a gear when climbing hills and a flush fixed both issues. I'll have to do some research on cleaning the filter.
 
  #12  
Old 03-28-16, 06:37 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Up until now, I thought it was supposed to be changed every 30k
That's true if you start from the first 30,000. After 100,000 miles, things change.
 
  #13  
Old 03-28-16, 06:37 AM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: USA
Posts: 6,211
MY 2 cents. Any oil or fluid be it tranny or engine oil will eventually break down. With that many miles on it I would drain and flush. If the tranny fails after that then failure was due anyway. Think about waht oil and tranny fluid is meant to do.
 
  #14  
Old 03-29-16, 02:46 PM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
I just checked my service records and I had a flush done at 97k. So I'm going to go ahead with a fluid change. Although I'm not going to fush it but rather do a few drain/refills a couple thousand miles apart.
 
  #15  
Old 03-29-16, 05:21 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Are you going to replace the screen?
 
  #16  
Old 03-29-16, 06:24 PM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
Sounds like a good idea, but then again so did flushing after what I thought was 100k miles. A new strainer and pan gasket is only $40 so I wouod say yes, I am going to replace it.
 
  #17  
Old 03-30-16, 10:34 AM
Member
Join Date: Nov 2007
Location: MI
Posts: 2,596
Originally Posted by Pulpo
People have blown transmissions if they changed the fluid when it had a brown color.
I'll have to remember this..."Change the oil only when it's not needed."

 
  #18  
Old 03-30-16, 11:13 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
I'll have to remember this..."Change the oil only when it's not needed."
Yeah, isn't that something.
 
  #19  
Old 04-14-16, 09:06 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
So I was looking over the service schedule for my new-to-me 2011 Acura TL and it says to change the transmission fluid every 120k miles. According to the advice given here, that would be a no-no. What should I do? Change it every 60k? It is now at 62k and it has never been changed.
 
  #20  
Old 04-14-16, 09:30 AM
Join Date: Apr 2016
Location: United States
Posts: 16
Most transmission advice will be vehicle specific. Some transmissions have screens, some have filters, some filters are external, some are internal, some fluids are meant to last 100,000 miles or better, some should be changed regularly at 30,000. Best to go with the recommendation from your manufacture.
Now if you don't know the history on a high mileage vehicle it is probably best to drain and fill. Pulpo mentioned "blown" transmission after a flush. This is a very real scenario, a true flush machine pushes new fluid in as old fluid is pumped out if you have a high mileage trans that has not had any flushes in the past this can remove tarnishes that have built up in the trans over time and change critical clearance for pressure. From the information provided it sounds like a drain and fill is your best choice. And yes if you have to drop the pan a new filter is a good plan. You will probably also find a magnet in the pan, be sure and clean and residue/metal shavings you find on it. Good luck.
 
  #21  
Old 04-14-16, 09:38 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 44,365
Without having the book handy to reference, I think my jeep calls for 100k+ transmission oil/filter changes unless it is severe duty which is 30k. I changed my oil/filter at 50k. I'd rather be safe than sorry.
 
  #22  
Old 04-14-16, 10:52 AM
Member
Thread Starter
Join Date: Mar 2009
Location: Northern Virginia
Posts: 3,659
I suppose I'll follow the manufacturer's recommendation of 120k, but can't imagine it would hurt to do it more frequently.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes