Removed Transmission Fluid And Its Reappearing? Wth?

yamihoo · September 16, 2009

Yeah newbie here, but not new to working on cars/trucks. I'm 37 been wrenching/driving since I was 13.

Yes I've searched and read 20 threads here and didn't find my situation. So here's my situation, just got a used 2000 GMC Sierra 4.8L 1500 4x4 has 150Kmiles one owner well taken care of (so I'm lead to believe)

On the freeway I noticed it seemed to go in and out of OD around 70mph. I watched the tach go from like 1800rpm to around 2000 (somewhere around there) So I decided to check the tranny fluid and it read like an inch overfull HOT! From what I've read this seems to be the TC locking and unlocking?

So i removed 2 qts to get it low "cold". Then I ran it hot and it was right in the good spot. Now today after I drove it today about 15miles and its overfull again by like 1/2". How much fluid is 1/2" on the stick?

Yes I'm checking level ground, good and hot. It does not leak anywhere, it didn't appear foamy on the stick.

Is it possible it was way overfilled, and the TC was overfilled, then when I took fluid out the TC drained some more back into the tranny? How does the TC fill up or release fluid, or does it at all????

Thanks in advance!

txab · September 16, 2009

Is it possible that it was way overfilled? YES! There are several threads here with just that complaint. Just make sure your fluid checking procedures are consistent. Fluid temp is about the same. (You can easily tell this by pinching the stick between your fingers). You want it to be at operating temp but overly hot. Another words, no pulling a heavy load and immediately check it at that point. Vehicle level and engine running. Go ahead and remove the excess fluid until you get it on the mark.

Has your OD been better after removing the 2 qts.?

*jblakney has an important point too below*

Starrman · September 16, 2009

Aren't you supposed to cycle it through all the positions/gears (P-R-N-D-2-1) right before checking it?

jblakeney · September 16, 2009

Sounds like its time for a new Radiator..... The tranie fluid passes threw the radiator tank to be cooled before returning to the tranie. You are probably swapping transmission fluid for engine coolant. Get ya a new Rad and do a COMPLETE FLUSH and FILTER CHANGE!!!! Might want to get a pressure solenoid that controls the lock up. That's what it sounds like your doing loosing lock up at cruising speed. Could be the fluid not holding pressure thou.

Flush out your coolant also and refill with dex cool to rid your engine of transmission fluid.

This is my method to the madness (Props to Black02Silverado I borrowed his instructions and modified them a touch.)

1. Make sure the fluid is warm. Warm up the car so the transmission is at normal operating temperature. Pull the transmission dipstick (located near the firewall in most cars). Fresh fluid is translucent and cherry red. Some darkening is normal, but if it is reddish brown or mustard color and smells like burnt varnish, it is worn out.

1a. Not totally required but you will have to bend it out of the way if you do not remove it the shifter cable bracket needs to get out of the way to drop the pan down. Some times you have to Disconnect the exhaust at the catalytic converter and pry downward on the pipes to allow the pan to come out. NOTE WELL do not FORCE the pan out you have 2 shift solenoids in the back that are easily broken (WHICH will cause the truck to not shift out of a gear after the change)

2. Drain the fluid by loosening the pan. Select the correct filter replacement based on pan shape and prepare a large pan to catch the fluid. Then loosen each pan bolt a turn or two and loosen one corner more than rest. Drain mostly from this corner. You might try the drain plug PRIOR to removing pan bolts but most plugs were over TORQUED from the factory.

3. Finish removing the pan and any gasket material from the pan or case. Avoid scratching the metal and make sure the pans gasket surface isnt bent or distorted. If it is still the OE Gasket you will not have any scraping to do just blue paper towel (scotts) it.

4. Remove the old filter. Wiggle the filter side to side while pulling down. The filter kit you purchased will have a metal/rubber seal. Feel the one thats in the whole where the filter came from if you DONT Feel a burr leave it alone. Rub some fresh transmission fluid before installing the new filter.

5. Install a new filter. Rub some fresh transmission fluid before installing the new filter.

6. Clean the pan thoroughly. Inspect the pan before cleaning. A small amount of fine grey clutch dust is normal. However, if you find metal shavings, there has been transmission damage. Clean the pan with solvent and wipe dry so there is no harmful residue.

7. Position gasket on pan. Some gaskets have four holes slightly smaller than the rest to allow four bolts through the pan and through these smaller holes to hold the gasket in place.

8. Hand tighten pan bolts in a criss-cross pattern. After that, use a torque wrench to tighten bolts to proper ft-lbs as per manufacturer (10 ft lbs, 120 in lbs).

9. Refill the transmission using only the amount shown as refill capacity in the owners manual using the type of fluid specified for the vehicle. Usually after the pan has been dropped 4qts is required here

10. If doing only a partial fluid replacement, skip to instruction 12 below. If doing a complete fluid replacement, follow the steps in instruction 11.

11. You now have replaced the fluid in the pan. To replace the fluid in the torque converter and oil cooler also, follow these steps.

Step 1. Obtain the total system capacity of the vehicle from the manufacturer. If you have a radiator problem I would recommend flushing at least 12 to 16 more quarts threw out the system after the pan change to get as much of the coolant out of the transmission.

Step 2. Disconnect the oil cooler line from the oil cooler. As you may not know which is the pressure side and which is the return side, have both directed so the stream of fluid will be directed toward a receptacle.

Step 3. With another person, be prepared to add ATF to the fill area as it is being pumped out of the oil cooler line.

Step 4. Start the engine, and as the old fluid is pumped out, add fresh fluid to the pan.

Step 5. When either the fluid color brightens or the total capacity has been replaced, shut the engine off and re-attach the oil cooler line. All fluids has now been changed.

12. Recheck the fluid level. With the car on level ground, set the parking brake and the transmission in Park or Neutral. Let the engine idle for a few minutes. Shift the transmission into different positions before returning the lever to Park or Neutral. Check the fluid level again and check for leaks.

Since I am a NAPA Jobber I will shoot the part #'s

Filter Kit ATP 1-8566 Shallow Filter

Filter Kit ATP 1-8567 Deep Filtration System ( Deep PAN )

Shift Soleniods ATP 1-5420 or ECH TCS608 1-2 & 3-4 (There are 2 of these and this is the ONEs that you can damage installing or removing the pan)

Pressure Control ECH TCS554

Hope this brings the problem into the light.

Jbo

jblakeney · September 16, 2009

Sounds like its time for a new Radiator..... The tranie fluid passes threw the radiator tank to be cooled before returning to the tranie. You are probably swapping transmission fluid for engine coolant. Get ya a new Rad and do a COMPLETE FLUSH and FILTER CHANGE!!!! Might want to get a pressure solenoid that controls the lock up. That's what it sounds like your doing loosing lock up at cruising speed. Could be the fluid not holding pressure thou.

Flush out your coolant also and refill with dex cool to rid your engine of transmission fluid.

This is my method to the madness (Props to Black02Silverado I borrowed his instructions and modified them a touch.)

1. Make sure the fluid is warm. Warm up the car so the transmission is at normal operating temperature. Pull the transmission dipstick (located near the firewall in most cars). Fresh fluid is translucent and cherry red. Some darkening is normal, but if it is reddish brown or mustard color and smells like burnt varnish, it is worn out.

1a. Not totally required but you will have to bend it out of the way if you do not remove it the shifter cable bracket needs to get out of the way to drop the pan down. Some times you have to Disconnect the exhaust at the catalytic converter and pry downward on the pipes to allow the pan to come out. NOTE WELL do not FORCE the pan out you have 2 shift solenoids in the back that are easily broken (WHICH will cause the truck to not shift out of a gear after the change)

2. Drain the fluid by loosening the pan. Select the correct filter replacement based on pan shape and prepare a large pan to catch the fluid. Then loosen each pan bolt a turn or two and loosen one corner more than rest. Drain mostly from this corner. You might try the drain plug PRIOR to removing pan bolts but most plugs were over TORQUED from the factory.

3. Finish removing the pan and any gasket material from the pan or case. Avoid scratching the metal and make sure the pans gasket surface isnt bent or distorted. If it is still the OE Gasket you will not have any scraping to do just blue paper towel (scotts) it.

4. Remove the old filter. Wiggle the filter side to side while pulling down. The filter kit you purchased will have a metal/rubber seal. Feel the one thats in the whole where the filter came from if you DONT Feel a burr leave it alone. Rub some fresh transmission fluid before installing the new filter.

5. Install a new filter. Rub some fresh transmission fluid before installing the new filter.

6. Clean the pan thoroughly. Inspect the pan before cleaning. A small amount of fine grey clutch dust is normal. However, if you find metal shavings, there has been transmission damage. Clean the pan with solvent and wipe dry so there is no harmful residue.

7. Position gasket on pan. Some gaskets have four holes slightly smaller than the rest to allow four bolts through the pan and through these smaller holes to hold the gasket in place.

8. Hand tighten pan bolts in a criss-cross pattern. After that, use a torque wrench to tighten bolts to proper ft-lbs as per manufacturer (10 ft lbs, 120 in lbs).

9. Refill the transmission using only the amount shown as refill capacity in the owners manual using the type of fluid specified for the vehicle. Usually after the pan has been dropped 4qts is required here

10. If doing only a partial fluid replacement, skip to instruction 12 below. If doing a complete fluid replacement, follow the steps in instruction 11.

11. You now have replaced the fluid in the pan. To replace the fluid in the torque converter and oil cooler also, follow these steps.

Step 1. Obtain the total system capacity of the vehicle from the manufacturer. If you have a radiator problem I would recommend flushing at least 12 to 16 more quarts threw out the system after the pan change to get as much of the coolant out of the transmission.

Step 2. Disconnect the oil cooler line from the oil cooler. As you may not know which is the pressure side and which is the return side, have both directed so the stream of fluid will be directed toward a receptacle.

Step 3. With another person, be prepared to add ATF to the fill area as it is being pumped out of the oil cooler line.

Step 4. Start the engine, and as the old fluid is pumped out, add fresh fluid to the pan.

Step 5. When either the fluid color brightens or the total capacity has been replaced, shut the engine off and re-attach the oil cooler line. All fluids has now been changed.

12. Recheck the fluid level. With the car on level ground, set the parking brake and the transmission in Park or Neutral. Let the engine idle for a few minutes. Shift the transmission into different positions before returning the lever to Park or Neutral. Check the fluid level again and check for leaks.

Since I am a NAPA Jobber I will shoot the part #'s

Filter Kit ATP 1-8566 Shallow Filter

Filter Kit ATP 1-8567 Deep Filtration System ( Deep PAN )

Shift Soleniods ATP 1-5420 or ECH TCS608 1-2 & 3-4 (There are 2 of these and this is the ONEs that you can damage installing or removing the pan)

Pressure Control ECH TCS554

Hope this brings the problem into the light.

Jbo

Take the truck for a quick run down the road long enough you make it threw the 1,2,3,4,lockup. Several times pull up and check the fluid on a Flat LEVEL ground. But if you check it every time in the same spot and its growing fluid its probably GROWING fluid......

This type system where the transmission cooler where it is inside the radiator tank are really BAD about doing this. If you do not get this attended to it will be the demise of the transmission. As you will begin to start slipping in gears due to the reduction of viscosity of the transmission oil being diluted by coolant.

Jbo

PS I had the same thing happen to my 01 2500 6.0 4x4 last year. I caught mine before it killed the transmission completely but its gonna need rebuilding in a year or two. As I use this truck to pull my 24ft gooseneck with 5x6 bails of hay during hay season (thats 1500lbs each 11 of them plus 6700lb trailer = 23200ish). That 6.0 and 4L80e pulls it like a champ!!!!!

yamihoo · September 17, 2009

Well I drove it 25 miles on the freeway at 70mph, stopped and checked the fluid twice along the way, its just at the bottom of the hash marks. So it appears to stop overflowing now. There is definately not coolant in the tranny fluid or tranny fluid in the coolant, I don't think the radiatior is the issue. It doesn't smell burnt, its red and seems pretty good. I think the place I bought it from recently changed the tranny fluid and overfilled it. But I wouldn't say its that clean, just pretty good.

Basically it goes back and forth between 3rd and 4th gear while I'm cruising down the highway. All other gears shift smooth and perfect!

If I let off the gas and coast, it will ride up to 2300rpm in 3rd gear, if I tap the gas or ease on the gas, it goes into fourth and rides about 1800 rpm. Honestly, I know a slipping tranny, this doesn't feel like a slip.

Furthermore, when I'm cruising 70mph and hit the tow button, the light comes on, but nothing happens, no shift down. Shouldn't it shift down to 3rd when I hit the tow button? Thats what my jeep does.

jblakeney · September 17, 2009

Well I drove it 25 miles on the freeway at 70mph, stopped and checked the fluid twice along the way, its just at the bottom of the hash marks. So it appears to stop overflowing now. There is definately not coolant in the tranny fluid or tranny fluid in the coolant, I don't think the radiatior is the issue. It doesn't smell burnt, its red and seems pretty good. I think the place I bought it from recently changed the tranny fluid and overfilled it. But I wouldn't say its that clean, just pretty good.

Basically it goes back and forth between 3rd and 4th gear while I'm cruising down the highway. All other gears shift smooth and perfect!

If I let off the gas and coast, it will ride up to 2300rpm in 3rd gear, if I tap the gas or ease on the gas, it goes into fourth and rides about 1800 rpm. Honestly, I know a slipping tranny, this doesn't feel like a slip.

Furthermore, when I'm cruising 70mph and hit the tow button, the light comes on, but nothing happens, no shift down. Shouldn't it shift down to 3rd when I hit the tow button? Thats what my jeep does.

You should see an increase in rpm's around 300rpm or 400rpm cruising, no T/H to T/H... I don't make a habit of hitting that button while the truck is moving. But Usually my truck no t/h at 80mph is 2000rpm and w/ t/h its like 2400rpm unless their is a trailer behind me inducing an extra drag but with out a trailer it will settle back a bit more. From what I have understood about the 4L60E/4L65E/4L70E/4L80E you have 4 gears and lock up (OD). (If we have Transmission specialist I would love a good explantion of this as GM 4speeds as the are very interesting I have never been in one YET.) All the T/H button does is bring you out of 1 to 1 Lock up with the basicly that is the Pump in the transmission is turn as fast as the turbine in the torque converter (for each turn of the turbine and pump makes a turn), thus acheving 1:1.

However I have seen this issue before on some other GM 4L60e's......... You might need to get it on a good scan tool genysis or tech2 or of like type (not a diy one).... You may have a transmission code present. I am assuming you have no check engine light burning while running.

Dunno where you are from but if your around my area I will scan it for you with my genysis NC just PM me.

Sometimes the radiators when they first start leaking coolant over it does it sometimes then doesn't others (like a plastic tank on a radiator does heat effects the leak to start with till it gets busted loose good). It took me a couple months to finally decide that is what my 01 was doing. I dont drive that truck much that 3/4 4x4 gas burner could use a mobile gas station in the bed!!

The fluid never appeard to be foamy and remained quite the same color on the stick.... I finally noticed it when I pulled the stick out and it hot and showing WAY over full probably 1 or 2 qts over and I did not wipe the stick but blotted the stick (kinda wrap a white paper towel around the bottom of the stick so you can get one big line on the white paper towel..... stuff towards the bottom of the stick dried darker red that the stuff at the top..... It got pinker at the top and darker red at the bottom). I confirmed the leak before changing the radiator.... pulled the fittings out and block the bottom off and put 80psi in the line and left it (should be able to hold at least 200psi by the way I called modine and asked)...... Took bout 3 minutes and it was depressurised FULLY.

Only reason I noticed mine was leaking over was I kept noticing it shifting a little wierd just did not feel like my 1/2 ton which is what it has always felt like. The shift was kinda week and spongy feeling.

But its a good chance NO water in fluid and NO DTC it could be a fuel filter or transmission filter. Low fuel pressure effects AT's in odd ways.... Fords will not pull out of Park sometimes (purchased a Explorer CHEEP this way from a dealer poor service guy never chaned it.... I drove it a couple weeks to make sure things was good fliped it and made several thousand on it still see if driving around town 2).... GM's loose gears at random.

Jbo

yamihoo · September 17, 2009

So I drove another 15 miles this morning, going through all gears, no change in fluid level. The 4th gear issue has not changed with fluid level corrections I've made. It really seems like a electrical control issue doesn't it? The Tow/Haul doesn't seem to make any difference, but I'm not towing either. The tach doesn't move when I put the T/H on and off, also I've kicked it down with the T/H on and off an there is no difference, it just shifts back into 4th OD it either way.

Correct, I have no codes present. Should you "feel" the TC lock/unlock? Or see RPM changes when it locks/unlocks?

So are you telling me the T/H button is not to be pressed while driving? Thats odd, all the vehicles I've owned you can shift in and out of OD while driving, seems thats what its intended to do?

jblakeney · September 17, 2009

So I drove another 15 miles this morning, going through all gears, no change in fluid level. The 4th gear issue has not changed with fluid level corrections I've made. It really seems like a electrical control issue doesn't it? The Tow/Haul doesn't seem to make any difference, but I'm not towing either. The tach doesn't move when I put the T/H on and off, also I've kicked it down with the T/H on and off an there is no difference, it just shifts back into 4th OD it either way.

Correct, I have no codes present. Should you "feel" the TC lock/unlock? Or see RPM changes when it locks/unlocks?

So are you telling me the T/H button is not to be pressed while driving? Thats odd, all the vehicles I've owned you can shift in and out of OD while driving, seems thats what its intended to do?

You can shift in and out while moving. I just don't.... So long as you do not change from D to R or P while moving. You can manually control 1,2,3,D while moving.

The Lock up is quite smooth when going into lock up. You should get in 4th and then in a second or to on a flat ground see the tach drop 300 or so rpm's. So count ever time you see the RPM's drop you should see 3 changes. Then a real small one. So 4 changes in RPM's. You will need a good LONG flat spot Mile or so.

You can cause Lock up to go On and Off. By pressing the brake petal lightly. When you have pressed the petal enough to turn the brake lights on it cause the Torque converter to UNLOCK get out of 1:1. If you have a factory exhaust still you can not hear the difference. Louder exhaust systems it is very noticeable.

By the tach making no change and NO DTC's I would say your going to have a pressure problem. Either you are not building enought line pressure or the pressure control solenoid is gone bad or quite possible disconnected (I have found this problem on a couple 4L60e's when changeing fluild the connector gets broke sometimes).

What kind of scan tool did you use to scan the truck. Not every scan tool will scan deep enough to retrieve transmission codes that are pertinent do this. Some transmission codes do not flag the MIL.

Jbo

txab · September 17, 2009

You may find some answers about tow haul in this search.

You can engage tow haul while you're driving

yamihoo · September 17, 2009

Ok, now we are getting somewhere. I'm sorry I was incorrect, we scanned for codes again and got P1870, I think the reader didn't work the first time. I assumed there were none anyway, because the check light was not on. I read on the code and found this, does seem to be a TCC problem doesn't it?

Here are the main causes for P1870 which is the code for slippage. There was a TSB for GM trucks for this problem and the fix was modifying a ground wire I think. The other cause is the bore for the TCC solenoid gets worn and the the plunger hangs up in the bore preventing the torque converter lockup. The valve body needs to be removed and the bore and plunger repaired. Generally the fix is anywhere from $250-500.00. The other thing I was told that causes this is sometimes one of the checkballs wears through the valve body. In either case until you get it fixed shutting it of and restarting it works sometimes or drive in third. Never drive in 4th when it is acting up or you will overheat the trans. Your other option is to have the whole trans done. I had 176,000 miles on my truck when I got the code so I opted to have the trans rebuilt.

Diagnostic trouble code P1870 (Transmission Component Slippage) is a General Motors-specific code whose set parameters are determined by transmission type and engine size. The PCM monitors and compares engine speed to vehicle speed after the converter clutch has been commanded ON in either high gear or Overdrive. Should the expected rpm ratio exceed predetermined parameters, DTC 1870 sets. And upon doing so, the PCM elevates the transmission main line pressure and stops converter clutch apply.

the PCM also will inhibit 4th gear and may or may not illuminate the MIL. This really is an added safety strategy, as the PCM had already monitored the upshifts and determined all was well through those ranges. Once the vehicle has made it to a cruise state, the PCM then begins to monitor the vehicle's cruise ratio. If at some point the transmission begins to slip, P1870 sets and line pressure is elevated in an attempt to stop any further slippage and prevent further damage.

jblakeney · September 17, 2009

Here is the excerpt from the GM Service Manual

It is a pdf and an inlarged GIF picture. This contains what happens in the With the lock on aka T/H off.

Jbo

yamihoo · September 21, 2009

Here is the excerpt from the GM Service Manual

It is a pdf and an inlarged GIF picture. This contains what happens in the With the lock on aka T/H off.

Jbo

Thanks! This would definately explain my fluid going up and down. I drove 300miles this weekend, after stopping and checking the level at similar intervals, and then after cooling and driving again, the fluid was up and down. After sitting overnight, it was about an inch over full. then the next day, it was back down to cold level. When I check it hot, its also never consistent.

So this would explain the problem, the TC is not releasing the fluid when it should, due to something with TCC valve and converter clutch apply valve by the sounds of it.

Well I'm bringing it in to the dealer tomorrow, I purchased an aftermarket warranty. Thanks for all the info!!!

I will follow up with the diagnosis soon as I know.

06Voy · September 21, 2009

Ya I had this happen almost a year ago it would start locking and unlocking on the highway. My transmission ate 2 of the check balls. Needed a complete overhaul.