I overfilled my Transmission

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svdsinner

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I made the mistake of trying to add a bit of transmission fluid to my truck ('98 2500 5.9L gas V8) early in the morning while still 3/4 asleep. I used a galleon jug of ATF and poured WAY more in than I should, hopped in and drove off.

Within a few miles, I realized it wouldn't shift past 2nd gear, and realized what I had done. I turned back and limped home. I checked the dipstick (something I was too asleep to do earlier) and the level on the dipstick was 6-8" above the MAX - don't overfill line.

That evening I siphoned out the excess and did a brief test-drive. It took coaxing, but it did finally up-shift into 3rd and 4th. However, it is still much slower to up-shift than it was. It did seem a bit like it got better after a bit of driving, but I didn't want to drive it too far. (Not sure how the dynamics of the fluid, air bubbles, etc. play into this.)

How bad is it that I drove roughly 10 miles with it overfilled? Are there any seals, etc. that I may have wrecked, or is it likely to work again now that the excess has been siphoned out? Anything I should be checking for?

FWIW, I was already planning on replacing the ATF and adjusting the bands this weekend. The bands haven't been adjusted in quite some time and ?might? be involved with the slow up-shifting.
 

DodgeTx

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What atf gallon did you put in? I have not been able to purchase the correct atf+4 in a gallon at any retailer over my time with these trucks 7+ years.

In the event you did not use atf + 4, you need to remove the pan and remove all the contaminated trans fluid immediately before driving again.

I recommend removing the return inlet line on the side of trans and attaching a hose to multiple containers or a large 5 gallon bucket. run it until it starts dribbling out (empty) remove the pan change the filter and gasket put it back together and refill with atf+4 only in neutral. put about 4 quarts in before you even start the truck, then continue to fill a quart at a time until you reach the correct level.

You may think this is overkill, but I have had a two rams get bad trans on me, one was from giant tires and mudding which got water into trans. the other was from a blown line and only being able to get atf type f. it now doe not easily go into overdrive or even the gear before it. I've done this same procedure to it twice already.
 

dapepper9

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Don't run the vehicle with open trans lines. Quick way to burn up converter.

Drop the pan, service like normal (fluid, filter, bands) and verify fluid level after dumping approx 75-80% of max by having the engine running and in neutral. Before checking level, warm fluid slightly by shifting it through all gears 3-4 times. Don't have to drive it, just slowly shift into each gear.
 

ouch1011

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If you overfilled it with the correct fluid, all you need to do is correct the fluid level and proceed with the service you had already planned on.

If you overfilled it with generic atf, not something odd like type F, then you do need to try to get all the fluid out, but the likely hood of any irreparable damage caused by using generic atf to an otherwise sound transmission over that short distance is pretty unlikely. The primary difference between ATF+4 and generic ATF like Dexron3 (not 6) or Mercon fluid (with no extra numbers or letters after it) is that it has a high level of friction modification. Without going into details, this allows for smooth shifts and torque converter lockup with the materials Chrysler uses in their transmissions. It has (almost) everything to do with the clutch material and very little to do with the seals and the metal moving parts (I.e the parts that would affect shift timing). I'd say that if damage was done, it is much more likely to be due to driving it with overfilled/aerated fluid and not the type of fluid used.

Either way, good luck!!
 

EvilSpirit

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OK - you have 2 issues. Probably re-hashing some things here, just trying to be thorough.

First, if the wrong fluid was used, good chance that the friction modifiers may not be compatible with the Mopar clutch materials. At the very least, the recommended ATF +4 is a full synthetic fluid, and has a higher operating temp window than most other fluids. So if you used the wrong fluid, a THOROUGH flush should be done. More on that later.

Second - the over-fill. At that height, the fluid level is high enough that the spinning clutch/drum/planetary assemblies can whip the fluid into a foam, trapping ail in the fluid, making it "compressible". Your truck, being a 98, uses an electronic sensor to read governor pressures and can get inconsistent readings by the air in the oil and can cause all kinds of shift quality issues, not to mention the now compressible fluid wreaking havoc on clutch servo/piston applies. It usually takes a THOUROUGH flush, and sometimes a couple days for the air to fully get out of the fluid. Truth be told, just dropping the pan, changing the filter, and refilling doesn't do SQUAT in a contaminated system. This doesn't get the contaminated fluid out of the trans cooler, the lines, or the torque converter - you only get about 4 qts of fresh fluid in a 10 qt +/- system - you still have at least half of the fluid contaminated.

IMO - The best solution would be to get it to a shop that uses a true flushing system that drains the contaminated fluid and replenishes it with fresh with the engine running - the end result is a complete fluid change, since the converter and cooler gets cleaned of the contaminated fluid. Some shops actually will put a "cleaner" fluid in and run the vehicle a short time before doing the machine flush. After the machine flush, they do a fluid and filter change, and adjust bands as necessary. This isn't cheap, since it requires 12+/- qts of ATF +4 at roughly $6 or more a qt to do, plus filter, pan gasket, and labor. Not uncommon for a TRUE flush and service to be $200-300. Add in the later mentioned transducer/governor solenoid change and you can be $400 into this. Ouch.

Second best is to unhook the cooler return hose and run the fluid into a pan - engine running, trans in neutral - and try to add fluid at the same rate it is draining into pan. Do this for 7-8 qts. Hook line back up, pull pan, change filter and service bands. Fill as necessary. You probably get 95% of the fluid changed this way, and are probably in the $100-125 range.

Third - unhook both cooler lines and use low pressure compressed air at 20-30 PSI MAX to blow lines out both ways (if possible, due to check valves, etc. in lines), and re-attach lines. Drop pan, change filter and service bands. Personally, if I do this method, I loosen the 10 bolts that mount the valve body a couple turns and let sit over-nite - this lets the converter gravity drain about 1/2 way. Torque valve body bolts to 100 INCH lbs. Install pan, fill with ATF +4. Probably $75ish.

On another note - many shops will suggest changing the governor transducer and pressure solenoid while the pan is off on anything over 100K mile trucks. They are a frequent cause of shift related issues. Usually $75-100 for parts - not a bad idea if the budget allows. Many times the diesel trans guys sell upgraded kits, up to converting Allison solenoids to the valve body.

Hope this post gives you some info and explains why I make the suggestions that I do.
 
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SYKRAMMAN

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OK - you have 2 issues. Probably re-hashing some things here, just trying to be thorough.

First, if the wrong fluid was used, good chance that the friction modifiers may not be compatible with the Mopar clutch materials. At the very least, the recommended ATF +4 is a full synthetic fluid, and has a higher operating temp window than most other fluids. So if you used the wrong fluid, a THOROUGH flush should be done. More on that later.

Second - the over-fill. At that height, the fluid level is high enough that the spinning clutch/drum/planetary assemblies can whip the fluid into a foam, trapping ail in the fluid, making it "compressible". Your truck, being a 98, uses an electronic sensor to read governor pressures and can get inconsistent readings by the air in the oil and can cause all kinds of shift quality issues, not to mention the now compressible fluid wreaking havoc on clutch servo/piston applies. It usually takes a THOUROUGH flush, and sometimes a couple days for the air to fully get out of the fluid. Truth be told, just dropping the pan, changing the filter, and refilling doesn't do SQUAT in a contaminated system. This doesn't get the contaminated fluid out of the trans cooler, the lines, or the torque converter - you only get about 4 qts of fresh fluid in a 10 qt +/- system - you still have at least half of the fluid contaminated.

IMO - The best solution would be to get it to a shop that uses a true flushing system that drains the contaminated fluid and replenishes it with fresh with the engine running - the end result is a complete fluid change, since the converter and cooler gets cleaned of the contaminated fluid. Some shops actually will put a "cleaner" fluid in and run the vehicle a short time before doing the machine flush. After the machine flush, they do a fluid and filter change, and adjust bands as necessary. This isn't cheap, since it requires 12+/- qts of ATF +4 at roughly $6 or more a qt to do, plus filter, pan gasket, and labor. Not uncommon for a TRUE flush and service to be $200-300. Add in the later mentioned transducer/governor solenoid change and you can be $400 into this. Ouch.

Second best is to unhook the cooler return hose and run the fluid into a pan - engine running, trans in neutral - and try to add fluid at the same rate it is draining into pan. Do this for 7-8 qts. Hook line back up, pull pan, change filter and service bands. Fill as necessary. You probably get 95% of the fluid changed this way, and are probably in the $100-125 range.

Third - unhook both cooler lines and use low pressure compressed air at 20-30 PSI MAX to blow lines out both ways (if possible, due to check valves, etc. in lines), and re-attach lines. Drop pan, change filter and service bands. Personally, if I do this method, I loosen the 10 bolts that mount the valve body a couple turns and let sit over-nite - this lets the converter gravity drain about 1/2 way. Torque valve body bolts to 100 INCH lbs. Install pan, fill with ATF +4. Probably $75ish.

On another note - many shops will suggest changing the governor transducer and pressure solenoid while the pan is off on anything over 100K mile trucks. They are a frequent cause of shift related issues. Usually $75-100 for parts - not a bad idea if the budget allows. Many times the diesel trans guys sell upgraded kits, up to converting Allison solenoids to the valve body.

Hope this post gives you some info and explains why I make the suggestions that I do.


Well said. I think somebody’s been around tranny’s a long long time!
 

dapepper9

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Servicing as normal will remove any air bubbles with just a couple short drives where the trans is able to get up to temp. The temp and fluid flow will remove it and the dipstick tube will vent it. It's really not as dramatic as you make it sound. Just check fluid level for a few days after you go somewhere. Keeping an eye on it for a few days is something you should be doing anyways.

For what it's worth, it's not a sealed system. A regular fluid change introduces air. Having a full flush done is the 2nd easiest way to cause a trans problem, right behind never touching it.
 

EvilSpirit

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Yeah, if it just had air in the fluid, that alone will pretty much fix itself over a short period of time. The main issue is, if the wrong fluid was used, the contaminated fluid won't fix itself, which was the reason for the explanation on the various methods of fluid flush/changes.

To go further on the fluid. Many shops buy generic non-synthetic "dino" fluid (made from crude oil) by the drum and add the proper friction modifier as necessary. For the most part, this is fine - the trans shifts correctly and is a cost effective way to service many brands, and the fluid outlasts their warranty. The issue arises when a vehicle calls for ATF +4 or other full synthetic "lifetime" oils, which, among other things has a higher temp operating range. So in this case, if ATF +3 was added - it has the correct additives; the trans will function fine; but being dino oil, the fluid will break down sooner and at a lower temp. Bottom line is - Mopar superseded the +3 with the +4 because the +4 is a superior fluid.

I tried to give the O/P flushing options and explain why I suggested each one, along with costs involved. A pan drop and fill is fine if you are servicing a correctly operating trans that has the proper fluid in it. The whole issue is the possibility of incorrect fluid, and how to correct it. I'm not trying to sell him my labor, parts, etc and have nothing to gain by padding a service invoice. I hope whatever method he choses works well for him.
 
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