Transmission Flush

RTTBLT1

Well-Known Member
Wanted to get some input/feed back...I have always done basic maintenance after purchasing a used vehicle regardless of what or anything that I know from the previous owner that's been serviced. One (of many) of my top things to do is service the Transmission. Initially I get a Trans Flush at Valvolin, drive it appox 5k-8k miles and Service the Pan Gasket, Filter & Fluid and also inspect the valve body/interior condition of the Trans. After the initial Flush I never get it done again cause I know I will be keeping up on the Pan Service xxx amount of months/miles. But for quite some time I have heard many people say Trans Flushing on today's vehicles is recipe for disaster. Is this true?..should I be skipping the Flush and straight to the Pan Service?...what is everyone's thoughts/option on this?
 

gmcman

Well-Known Member
Current mileage?

Color/condition of fluid?

The only time I feel flushing the fluid is recipe for disaster is for a severely neglected trans. Generally when bad enough, the fresh fluid can dislodge the crud and clog the filter, thus starving the pump if not followed up on with a new filter.

If I was in your shoes, regardless of miles...what I would do only if the fluid was dark and nasty would be to change the pan fluid, then drive a tank of gas then do it again with a filter change.

But if it looks red or somewhat red and has between 120 and 140K, I would pull the valve body and replace the separator plate with a DEALER SEPARATOR PLATE because it's matched to your VIN. Not a huge deal but going in blindly it's the safer bet.

These plates get hammered by the steel check balls and will eventually result in pressure loss.

There are many things to to if you plan on keeping it, if so....a new plate, accumulator pistons, and the TCC eliminator valve to remove the PWM control from the torque converter lock....changes the variable lock to an OFF/ON lock and saves the TC clutch.

You can also add a vette servo.

If it's under 100K miles and fluid looks good, I wouldn't hesitate a flush. Just understand you need to follow up with subsequent filter changes. ...I personally go about 30-40K between flushes.
 

Mooseman

Moderator
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RTTBLT1

RTTBLT1

Well-Known Member
It has 165k miles, don't know much about it's history other than it seems it has been taken care of. I got a real good deal on it so I took the leap. The Fluid on the dip stick looks real good but haven't opened up the Pan yet. Shifts smooth and doesn't slam into Gear(s). Was just curious what others thought of Trans Flushing.
 

Jrgunn5150

Well-Known Member
When you say flush, I hope you mean having all the fluid syphoned out, not one of those quicky lube "total fluid exchagne" thing's.

You can do a proper flush in your driveway by simply unhooking a line and letting it pump the dirty fluid out.
 
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RTTBLT1

RTTBLT1

Well-Known Member
I've always taken my Vehicle's to Valvoline, so yes i quick lube shop. So Jrgunn5150, you saying places like Valvoline don't do the Trans Flush properly/throughly? And to just disconnect the Trans Line at the Radiator and do it at home?
 
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RTTBLT1

RTTBLT1

Well-Known Member
Thanks for sharing that Mounce. I can't believe how easy that is, it just like when I did the Flush/Bleeding on my 06 Impala after replacing the Power Steering Pump. I also placed a 4ft Section of 3/8 in Hose and Hose Clamp to the Return Line coming off the Rack to Flush/Bleed the system and that was pretty much what he did.
 

DIY Fixer

Well-Known Member
I was wondering can you really do the transmission flush with only one person? I mainly do everything myself on the driveway.
 

Mounce

Well-Known Member
If you can tie the hose to the bucket so that it don't become a snake and flip around from the pressure then I don't see why not. I imagine the right amount of duct tape would do just fine.
 

DIY Fixer

Well-Known Member
I will have to try that one day since I never change the tans oil when I bought my vehicle used at 109,000 miles on it. I am not even sure if the old owner or dealership I bought it from changed it. I have 115,200 miles on the vehicle now.
 

Mooseman

Moderator
Probably not. You'd better off adding an auxiliary cooler.
 

Sparky

Moderator
Only benefit I see to that is it has a drain plug, so if you were doing a simple pan drop and filter change without the complete fluid flush as shown in the May03LT video it would greatly reduce the mess. I almost went that route, but decided if I had the truck long enough that it would require another full fluid change I'd just do that again.
 

Mounce

Well-Known Member
Thinking it might be a good idea to put a drain plug in my pan when I finally do it. Then 50k down the line just do a fluid exchange and call it good till 100k to do a full flush again.
 

DIY Fixer

Well-Known Member
I see what you guys are all saying here but I am probably good with doing the flush at 115,000 or 116,000 when ever I have money to buy the ATF brand oil I like. I see Amsoil is the best brand on the market. I bought my 03 Envoy used at 109,000 so I don't even know what the old owner have done to the vehicle.
 

Mounce

Well-Known Member
We're cool with our way of flushing, it's the machine deal that gets us uncomfortable. Around my parts you've gotta sign a waiver removing liability from the shop if you're over 75k.
 

DIY Fixer

Well-Known Member
I would rather do it myself too and not have to deal with the crap the shop do while we have youtube on the other hand to show us.
 

hockeyman

Silver Supporter
I followed the video from May03LT and the trans flush/fill went completely smooth.
To get a snug fit on the trans hose, be sure you do what he recommended and use a 1/2" ID hose.

I cut a 1/2" hole on the lid of my drain bucket and used that to keep the hose from going buck-wild as the engine was running and the trans was draining. I also put a 75w droplight light behind the bucket so I could see what the fluid was doing and how high the level was going up to.

Other than the pan drop, it didn't make a mess at all.

Another tip is to lay out a tarp under the trans pan just before starting. That'll keep fluid from getting all over your floor or driveway.
 

RedEnvoyDenali

Well-Known Member
Let me add my voice to those above. Never "FLUSH" just change the tranny fluid on a regular basis. This consists of either a 1/2 change (drop pan and change filter and refill) or a complete change (pump out old fluid, change filter and refill). 1/2 will be about 6 quarts and complete double that.
Also I recommend a tranny cooler on all vehicles even if you don't tow. Heat kills tranny's and a cooler keeps this from happening. I also don't think you can over cool (although i run a Tru-Cool that has a build in temp sensor) all year long up here and -40 is not unheard of in the winter (but not this year thanks to EL Nino).
I don't subscribe to the other site but that is where pics of my install live so here goes the link.

http://forums.trailvoy.com/showthread.php?t=56573&page=3

remember i said heat kills, here is the chart that highlights that statement.

 

Jrgunn5150

Well-Known Member
I've always taken my Vehicle's to Valvoline, so yes i quick lube shop. So Jrgunn5150, you saying places like Valvoline don't do the Trans Flush properly/throughly? And to just disconnect the Trans Line at the Radiator and do it at home?
I'm saying they force fluid through, in a manner unnatural to the operation of the transmission, which leads to all sorts of mayhem potentially.

There's also the simple issue of, that process doesn't address the filter at all. You wouldn't just change your oil and leave the filter, and an engine oil filter at least has a bypass, a trans filter will just starve the trans when clogged.

I was wondering is there a advantage to changing the transmission pan to a cast aluminum with fins on it just like this picture.

Also www.yourcovers.com sell the same thing.
I have the Dorman pan with the plug in it, it was around 30 bucks, and makes servicing much easier.
 

DIY Fixer

Well-Known Member
Jrgunn5150 recently when I had my 1999 GMC Jimmy Envoy I done the same thing and added that Dorman steel transmission pan with drain plug on it only $32.79 at RockAuto. Here when it snow or rain the bolt for the drain plug tense to get rusted very bad but I guess I can just paint over it.
 

Jrgunn5150

Well-Known Member
Jrgunn5150 recently when I had my 1999 GMC Jimmy Envoy I done the same thing and added that Dorman steel transmission pan with drain plug on it only $32.79 at RockAuto. Here when it snow or rain the bolt for the drain plug tense to get rusted very bad but I guess I can just paint over it.

I live in Michigan, I put mine on last year and it seem's fine? I honestly can't say because I haven't tried to bust it loose again just yet, it still has a few miles to go. So I guess time will tell.
 

Sparky

Moderator
I personally feel it is a bit overrated and having to go through some dealer network more of a nuisance than it is worth. Not saying it isn't good oil. Just my opinion.
 

triz

Well-Known Member
I personally believe their transmission stuff is one of the best out there. I started using it my MR2's after using Redline.
 

smt 59

Well-Known Member
I have been using Amsoil since 1979 as my Dad was a dealer and never used anything else since. Even the GM dealership up here uses it now!
Used to be Amzoil back in the day. lol
 

Mooseman

Moderator
If you buy any brand that says Dex VI, it must meet GM specs for it. It's a licensing thing.
 

DIY Fixer

Well-Known Member
@Jrgunn5150 I know what you mean that Royal Purple crap is just a brand name and does nothing well. I only put it in my 99 GMC Jimmy Envoy because I had the money and that basically about it. Have lots of money buy whatever you desire.
 

Mooseman

Moderator
Personally, Amsoil smells of Amway to me. It probably is good stuff but not worth the extra for a daily driver. Dex VI is already way ahead of the old Dex III that was the original fill in our trucks (2005 and older). Now that Dex VI has become more mainstream, it's easier and cheaper to find.
 

triz

Well-Known Member
wonder can you buy Amsoil just right off their site though.
Lubedealer.com/mr2ner

All orders go through amsoil when you order online.

Personally, Amsoil smells of Amway to me. It probably is good stuff but not worth the extra for a daily driver. Dex VI is already way ahead of the old Dex III that was the original fill in our trucks (2005 and older). Now that Dex VI has become more mainstream, it's easier and cheaper to find.
There is no relation though. It's a popular product and a good one. The transmission stuff again is probably one of the best out there.
 
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