4L60e.... To flush or not to flush?

zaid3ssaf

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Jan 1, 2020
151
Midwest
Back to the dreaded transmission flush. My 02 Bravada with 230k miles shifts little hard on first and second gears especially when cold.But Otherwise, the transmission works great. I have no idea when was the transmission fluid changed last (if ever). I am inclined to flush and drop the pan. But everyone seems opposed to that at 230K so I am not sure if flushing it cause the clutch packs to slip or any other problems.

Fluid looks like this and while it doesn't smell tart (or whatever), it only smell slightly burnt
1601128984179.png
 

Reprise

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Harder shifting when cold isn't unheard of; the ECU (or TCM, if you have an '05 and up) increases line pressure when the trans is not yet up to operating temperature. The worse situation is when the trans fluid gets overly hot; shifts will get *really* firm, then.

Anyway, if you don't know *any* maintenance history, some people say "leave it as-is", with that mileage. Not to scare you, but you're about at the mileage where the 4L60e in our trucks give their last, and need repair / rebuild / replacement (take your pick). If it does go out at some future point, figure that you got your money's worth out of the OEM / stock trans.

Since you're saying that the fluid doesn't smell sweet / look pink, I don't see the harm in doing a pan drop / filter change / refill w/ 5qts of new fluid.

If you want to do a more thorough job with fluid replacement, you can do a fluid replacement yourself. You'll need about 15-16 quarts of fluid, and you'll be letting the car pump out 1-2 quarts of fluid, then shutting it off and replacing that same amount. Do it after the pan drop / filter change / fluid refill, as that'll be 5 less quarts you need to worry about, and wastes the least amount of fluid. I used a gallon jug with each quart marked off / dashed line across the outside, so I could see it from the driver's seat and turn the key off, each time. And I think I have a post somewhere on this site on how I did this, in detail. There are also other threads by people here showing how they did it, as well. Take a look.

The thing you *don't* want to do is have a machine 'reverse flush' the trans, or add some sort of cleaning solution to their machine. Those are the things that dislodge the small pieces of wear items that have been collecting in the trans, and would be in a 'safe' spot, except for the flushing machine coming along and moving them around into places where they harm the functionality of the unit. That's also when you wind up doing a rebuild or replacement on them.

There are places that don't use 'reverse' flushing; they can be OK to use, if you're not a DIY kind of guy. Most of us here do it ourselves. If you have an assistant, it's pretty much child's play, but you *can* do it on your own - I did, using the method I mentioned, above. Besides the gallon jug, you'll also want some clear tubing, so you can see when the fluid starts running clear.

If you want to really get fancy / be fastidious, you can get the fitting adapter that's used for installing external trans coolers, fasten it to the upper outlet in the radiator, connect it to the tubing, and you're all set (it's also a safer way, if you're doing it all by yourself.)

One last thing - depending on the year of your truck, it may specify Dexron III as the replacement. Use Dexron VI, instead; it's backward-compatible, and GM specifies it for vehicles that were running the older spec. It's hard to find Dex III anymore, anyway (although I do have one place around here that still sells it).
 
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gmcman

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Dec 12, 2011
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The fluid looks to have a slight pinkish hue so that's good.

I would drop the pan and change the fluid that came out with the pan and the filter, the filter is key for longevity.

The less messy way is to remove the passenger side (double check that) cooler line and use a 5/16" ID tube into a bucket, start the engine and shut the engine off when the fluid starts to sputter. This will empty the pan and should require about 5 qts to replace.

I use the gallon jugs of Valvoline Max Life.

Don't fear the mileage too much, just be observant of the tack needle when shifting, shouldn't rise up a couple hundred RPM.

At your mileage, it would be wise to replace the seperator plate with one from the dealer. About $30 and is generally the culprit when pressures start to go wonky. At the same time, replace the accumulator pistons as some can develop cracks.

Those are good preventative maintenance steps and not terribly difficult if you are comfortable with a wrench.

You WILL need an inch pound torque wrench.
 

MBS1994

Member
May 26, 2019
326
Colorado
Not to hijack just a quick question. 5 qts to drop the pan and change filter which I would need to do my shift kit but if I wanted to pull the tranny to do the full kit and converter would it be more than the 5 for the pan drop and 2 for the converter? I know with mine I need to pull the tranny to do the boost valve and have been curious on this.
 

Reprise

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Not to hijack just a quick question. 5 qts to drop the pan and change filter which I would need to do my shift kit but if I wanted to pull the tranny to do the full kit and converter would it be more than the 5 for the pan drop and 2 for the converter? I know with mine I need to pull the tranny to do the boost valve and have been curious on this.


From what I remember of the listed capacity specs on these, it's 13-14 quarts when overhauled (and it takes that plus a little more to flush it). Now, if you don't drain that much out of it, that's fine - just put back in what you get out of it. (Note the chart below, however).

Since the boost valve is in the pump assembly, and that's pretty much right behind the converter, you may get the pump out w/o too much extra fluid loss, depending on how you do it. I'd stand it on end, if I could, but I don't know what your garage situation is like.

And you're smart to remember that it's better to pre-fill the converter, too, rather than let it run dry while the pump replenishes the fluid to it. If it comes out w/o too much fluid loss, I'd consider draining it, just to see what you get out of it, for quantity. Then refill it before reinstalling. The stocker is a 10", so according to the chart below, it takes 3qts total.

If you do the boost valve, I know we'd all like to see a write-up and some pics, if you're feeling up to it :thumbsup:


Here's what TCI lists on their site for fluid quantities (I edited the pic, as there was a non-GM trans at the bottom):

1601146528889.png
 
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MBS1994

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May 26, 2019
326
Colorado
From what I remember of the listed capacity specs on these, it's 13-14 quarts when overhauled (and it takes that plus a little more to flush it). Now, if you don't drain that much out of it, that's fine - just put back in what you get out of it. (Note the chart below, however).

Since the boost valve is in the pump assembly, and that's pretty much right behind the converter, you may get the pump out w/o too much extra fluid loss, depending on how you do it. I'd stand it on end, if I could, but I don't know what your garage situation is like.

And you're smart to remember that it's better to pre-fill the converter, too, rather than let it run dry while the pump replenishes the fluid to it. If it comes out w/o too much fluid loss, I'd consider draining it, just to see what you get out of it, for quantity. Then refill it before reinstalling. The stocker is a 10", so according to the chart below, it takes 3qts total.

If you do the boost valve, I know we'd all like to see a write-up and some pics, if you're feeling up to it :thumbsup:


Here's what TCI lists on their site for fluid quantities (I edited the pic, as there was a non-GM trans at the bottom):

View attachment 97329
I have about a 60x20 workshop as long as I can get it done on a weekend. I wouldn't be apposed to doing a write up or at least taking pictures of trans removal, shift kit, and torque converter when the time comes as a pay back for the knowledge and help this site has provided. Just gotta figure some gremlins out first with maintenance
 

zaid3ssaf

Original poster
Member
Jan 1, 2020
151
Midwest
trans is not yet up to operating temperature
It still shifts little hard even at operating temp. In subzero winter it very noticeable.

If you want to do a more thorough job with fluid replacement, you can do a fluid replacement yourself. You'll need about 15-16 quarts of fluid, and you'll be letting the car pump out 1-2 quarts of fluid, then shutting it off and replacing that same amount. Do it after the pan drop / filter change / fluid refill, as that'll be 5 less quarts you need to worry about, and wastes the least amount of fluid.
I agree. That would be 5 quarts less. I was planning not to get messy so I planned to start by letting the car pump out whatever in the pan through the cooler line at idle, then drop the pan and change the filter, fill it up with 5 quarts, let it pump them out again, and then fill it up to the correct level. So that would be about 15 quarts. Is that what you were referring to?

I was going to follow a method I found on Trailvoy a long time ago as shown by @MAY03LT

Dexron VI, instead;
Walmart has a deal for $17/gallon. :2thumbsup:

he less messy way is to remove the passenger side
You are correct, it on the passenger side.
seperator plate with one from the dealer. About $30 and is generally the culprit when pressures start to go wonky. At the same time, replace the accumulator pistons as some can develop cracks
I dont think I'm brave enough to do the pistons (or even the seperator plate). I think the accumulator piston is the one shown at 13:30. Is that 1-2?
 

gmcman

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Dec 12, 2011
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I dont think I'm brave enough to do the pistons (or even the seperator plate)

Honestly, it's not much different than removing the pan, only another group of bolts. Once the pan is off, then you remove the bolts holding the valve body. Once the valve body is unbolted, slide the shift lever arm from the valve body and lower the valve body. The seperator plate is basically a "metal gasket" between the valve body and trans case.
 

Reprise

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@zaid3ssaf -- You were looking at gmcman's answer to the other poster who jumped in the thread. You should not be doing anything more than changing the filter. Don't go farther than that. And since you're removing the pan to do that, you need a torque wrench. 3/8 drive would be ok to do the pan bolts.

Re: how to replace the fluid... I do mine differently than most people here (I don't pump as much fluid out before shutting off the engine.)
That said, many, many people have done it the way you see in the video, and didn't hurt anything, so you should be ok to do it that way, too, if you prefer.

@gmcman -- 50 lashes with a wet dipstick for you, for confusing the two posters with one another! lol
 

gmcman

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Dec 12, 2011
4,643
50 lashes with a wet dipstick for you, for confusing the two posters with one another! lol

I think I answered correctly.....:undecided:, I replied to zaid and zaid is the OP, my mention of the seperaror plate was preventative maintenance at that mileage.
 
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Reprise

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You know what? You're right, and I'm wrong. Removing my shirt, so you can administer the punishment.:dielaugh:

That said, I don't know if he should do the separator plate, etc., b/c I'm not sure he's comfortable doing it. And there's a couple of things he's going to need to account for... gaskets (the correct ones) for the plate, and the 3 different length bolts in the VB.
(@zaid3ssaf -- if you're reading this and thinking 'huh?' -- that's a pretty good sign to just do the filter / fluid.)
 
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zaid3ssaf

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Jan 1, 2020
151
Midwest
You know what? You're right, and I'm wrong. Removing my shirt, so you can administer the punishment.:dielaugh:

That said, I don't know if he should do the separator plate, etc., b/c I'm not sure he's comfortable doing it. And there's a couple of things he's going to need to account for... gaskets (the correct ones) for the plate, and the 3 different length bolts in the VB.
(@zaid3ssaf -- if you're reading this and thinking 'huh?' -- that's a pretty good sign to just do the filter / fluid.)
lol Automatic transmissions have always been this obscure magic box that I don't mess with. @gmcman is probably right about the preventative maintenance. I have been watching videos of "precision transmission" youtube channel tearing 4L60e's to help understand them, but I'm more sure now that I don't want to mess with them. Filter and and pan is easy mode though.
 

Reprise

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I think that's a good plan.

Note, that if you were comfy with doing the work, I'd be on board w/ gmcman, as far as you doing it.
 
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Dec 5, 2011
555
Central Pennsylvania
FWIW I "flushed" my 4L60E at 250,000 ish miles. Well, did the fluid "exchange" a la MAY03LT's video. I've had 0 problems since. Shifts are crisp and timely and fluid has remained deep pink like it's fresh from the bottle for over a year (20,000 or so miles).
I did pump out the pan by removing a line from the cooler and attaching a hose to a bucket, removing the fuel pump relay, and turning the key until it was pumped out. I then applied a little bit of air to the return line to push the return fluid to the pan before dropping the pan, replacing the filter and gasket, and reinstalling it. It's then a matter of putting in fluid to replace what you pump out. I used clear vinyl tubing so I could see when the fluid color changed, but then didn't pay close enough attention. I ended up using 4 or five more quarts than I needed, but the fluid was pristine by the time I figured it out.

It IS a little scary trying this yourself, but once you see the fluid pumping out it's obvious it's needed. Just follow the video and you should be good to go. As for replacing any "parts" (separator, etc.)... I didn't want to turn a single bolt inside the tranny and I didn't and wouldn't recommend it. It's working as is, the fluid will only prolong the life and MIGHT improve your shifts. I picked up a half MPG or more as well.

One thing I should mention, though. A year or so after I did the flush (probably unrelated) and immediately after replacing my exhaust manifold (definitely related) I started getting a fairly large amount of transmission fluid leaking onto the ground any time I stopped on an incline. I discovered that the transmission dip stick tube seal was shredded. It's a $2 part. I paid $8 for it and I'd do it again. Not "difficult" to change, but tricky enough as it's at fingertip position. It might be worth while to change that seal (grommet, really) while you're under the car and in the tranny area.

Requisite words of caution: do not get under any vehicle without it being properly secured on jack stands or something rated equally for supporting the vehicle. I also NEVER get under a vehicle without placing the wheels I removed (if I remove any) under the frame of the vehicle. The life you save could be your own.
 

zaid3ssaf

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Member
Jan 1, 2020
151
Midwest
Requisite words of caution: do not get under any vehicle without it being properly secured on jack stands or something rated equally for supporting the vehicle. I also NEVER get under a vehicle without placing the wheels I removed (if I remove any) under the frame of the vehicle. The life you save could be your own.

I purchased the filter and gasket and will be doing them this weekend once I figure out the torque for the pan. I am not planning on jacking the car up at all. Would that be an issue?
 

JayArr

Member
Sep 24, 2018
486
Mission BC Canada
It'll be harder to drop the pan but otherwise not a problem. Ramps would be a good solution.

Here's something else to think about, Dorman 265-811 sells a replacement, deep pan WITH a drain plug for about $39. You'll need to buy the matching deep filter but now is the time if you want this. The drain plug means you'll never get covered in ATF fluid again and the pan holds an extra quart or so which helps keep the fluid temp down.
 
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zaid3ssaf

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Jan 1, 2020
151
Midwest
It'll be harder to drop the pan but otherwise not a problem. Ramps would be a good solution.

Here's something else to think about, Dorman 265-811 sells a replacement, deep pan WITH a drain plug for about $39. You'll need to buy the matching deep filter but now is the time if you want this. The drain plug means you'll never get covered in ATF fluid again and the pan holds an extra quart or so which helps keep the fluid temp down.
That would be a good investment for those who plan to keep their trucks longer. At my truck's age, I don't think it'll make it to another transmission flush :sadcry:
 

zaid3ssaf

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Jan 1, 2020
151
Midwest
Thank you all for the helpful comments. I did the flush last week. I took the cooler line out and let it pump all the old fluid out, then I dropped the pan and installed a new filter. I replaced one gallon at a time and let it pump it. It used about 2 gallons after which I did a final fill with about 5 quarts. so 3 gallons total.

Now after 200 miles, it runs little better. No signs of slipping. Still shifts hard between 1st and 2nd but the rest are much smoother. I will give an update at 2000 miles, but for now, I sleep much better knowing that I have cherry red fluid in my tranny
 
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Reprise

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The 1-2 will always be a little harsher, relative to the other gears, because of the difference in ratios between the gears. Mine has always been firmer, both before it was rebuilt, and after (feels the same, tbh). And I even have different parts in mine, vs. stock - no change when I put those in, either.

(on a side note: the smoothest shifting GM trans I ever had was in a '98 Grand Prix; it had a 700R4 (precursor to the 4L60e). You could feel the 1-2 if you were waiting for it, the other shifts were damn near imperceptible (you'd literally have to look at the tach for confirmation.)) After that car, I got away from GM for a bit, and only came back to them about 5-6 years ago.

Back to the 4L60e: This goes against logic a bit, but the *softer* you accelerate, the *harder* it'll shift into 2nd, after the fluid temp warms up (as I mentioned above, line pressure is higher when cold, so it'll always be more harsh, then)
Also, if you want a softer shift, you can let up on the pedal a little *just* before the 1-2, and you'll notice it shifts more softly. Frankly, this is a lot of trouble to go to, on a regular basis, IMO. But it's an option, if you want to feel a smoother 1-2 shift.
 

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