- Joined
- February 8, 2003
- Messages
- 9,824
- Reaction score
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- City, State
- Sacramento, CA 95827
- Year, Model & Trim Level
- 1992 XLT
I have had a few inquiries if I might post a kind of "common problems" and diagnosis thread for trannies. This is my attempt to do so. I will not lock this thread but keep adding here (and maybe deleting follow on posts after I have them answered here to keep everything manageable - folks posing Q's with answers will have good ones posted here with attribution.)
So, specific inquiries below will be answered in the top thread and eventually we will hopefully have a comprehensive diagnosis thread here by tranny type is the plan. For now A4LD, 4R44/4R55 and 5R55 as well as 4R70W. More or less Explorers through 2002. Save a lot of answering similar Q's over and over.
A4LD COMMON PROBLEMS
Q1. I have a delayed engagement into reverse (sometimes also into drive). Why is this and how can I fix it?
A. In the A4LD the reverse band is used to engage both reverse and 1st gear. The servo that engages it has a seal prone to leakage, and it also has a rather large volume that needs to be filled and pressurized.
More often that not this is the culprit. Sometimes a leaky seal, sometimes a slow fill because of VB issues. About 50% of the people will find a fix in replacing the seals on the low/reverse servo with either a "double lip" upgrade, or a "D ring" seal kit. Both are cheap (under $5) but you have to drop the pan and valve body to get to it.
Good news? If you can live with it, it isn't doing any harm, just be patient before you goose it.
Q2. I get a loud "klunk" when I shift into reverse. Is this serious? What causes this?"
A2. Generally the "klunk" you hear is caused by worn U joints. The delay in the application of the low/reverse band can cause a sudden engagement, which causes the slack in the U-Joints to be taken up suddenly ..producing that noise. Dangerous? Serious? Hmmmm. Not really. Though the continual "hammering" of the bad joint will only make it worse. Might want to look at those joints, but life threatening? no. Relax.
Q3. I am lacking the 4th gear shift into OD. (The so called 3-4 shift)
A3. In the A4LD, the shift from 3rd to 4th (or the so called 3-4 shift) is controlled by a solenoid. In the majority of cases wherein there is a 3-4 shift lacking, either the solenoid has problems, the wiring to it has a probem, or a screen on some models may be plugged up. Checking the wiring and for voltage at the main feed wire to the solenoids is a first place to check. Many times lack of 3-4 will also have a lack of Torque convertor lockup too. This can add heat to the trans, and the common lack of 3-4 and TCC lockup usually is a good sign of an electrical issue, as neither solenoid is operating correctly. Often this issue may relate to the wiring harness to the PCM (computer). [Brooklyn Bay adds the following good observation: The PCM takes sensor inputs from various places, such as the Vehicle speed sensor, Brake On/Off switch, and Throttle position sensor to calculate when to apply a ground signal to the A4LD's solenoids to apply or not, or in the case of the Torque convertor clutch to lock, and unlock. Often, there could be a driveability problem due to one of these solenoids because of a bad input to the PCM from one of these sensors, and it might be mistaken for a solenoid problem when in fact it is not.]
Q4. I am going through ATF every with no apparent leaks. The transmission pan and rear seal is dry. The front seal appears to be dry. The radiator does not appear to have trans fluid in it either. The driveway is clean under the vehicle. Please help!
A4. The modulator on the A4LD can develop a tear or vacuum leak, and the fluid can be sucked into the engine. While logic would suggest it would be burned as part of the intake gases, it does show up as an overfill in the engine oil area. You can check for this by pulling a vacuum hose from the modulator and looking for ATF in the hose, but if this is your symptom, odds are about 100% you have a bad modulator. It needs to be replaced. It is on the passenger side behind the heat shield with a hose going to it.
4R44E/4R55E/5R55E COMMON PROBLEMS
Q1. My 4R/5R is starting to display an OD light that is flashing, and the shifts are sometimes late, or "soft".
A1. These transmissions use an electronic pressure control (regulator) solenoid (EPC) that works hard to maintain a contant pressure as commanded by the computer. It seems these have a useful life of 65,000 miles on the low side and about 150,000 miles on the high side. In addition, these transmissions were prone to blowing out main control (valve body) gaskets. FORD came out with a technical service bulletin (tsb) on these issues and there is a kit that modifies the VB and changes the separator plate and gaskets. I recommend whenever there is this issue to change out the EPC. It costs about $115. The FORD mods are about $30. This is a good time to upgrade the Valve body too. (See separate Q on this below).
Q2. I have a 5R55E transmission in my late 90's Explorer. I am strating to notice some shifting issues in the shifts between 1-2 and 2-3 ... kind of soft or dealyed and the RPM's will increase a little until the next gear engages. Is this serious? Is there something I should or could do to fix this?
A2. While, in fairness, there can be multiple possible causes for these symptoms, in general a majority are related to either leaking valve body (Main control) gaskets, or an Electronic Pressure Control Solenoid that is getting tired. When I hear of this problem, I generally refer folks to the 5R55E Valve Body Rebuild Diary here in the stickies, and also recommend a "shift kit".
What is a shift kit?
A Shift kit is an aftermarket engineering attempt to fix deficiencies in the original design. In many cases the actual manufacturer will pick up on some of these fixes and incorporate their own in later versions of the design. Overall, the 5R55E is a transmission with weaknesses in the Valve Body that shift kits address nicely. I recommend that if you ever have a need to remove the transmission valve body you have a shift kit installed. I think it will improve the life of your transmission.
GENERAL QUESTIONS
Q1. How often should I change my transmission fluid?
A1. The general answer is one of those "it depends" kind of answers. Remember the manufacturer only has to warranty drivetrain for a finite period. They will give a long interval, and then cover their a**es by saying "In Heavy Duty Applications... blah blah blah.."
One school says change it every 15,000 - 20,000 miles. Another says maybe every 30,000 to 40,000 unless you tow or tend to offroad or use big tires.
If you use yours on streets and highways and do no towing, I think a change every 30,000 to 40,000 miles is fine. Add towing and I am back to 15,000 to 20,000 miles.
Automatic transmission fluid is a rather unique product. The additive properties get destroyed by heat and age. They are important to help keep your transmission from slipping, and at the same time lubricate necessary parts. See how odd that sounds? Did you know that ATF used whale oil as a component part until harvesting whales was banned by international treaty?
Q2. Should I have a "fluid flush"?
A2. More and more we see places (like Jiffy Lube etc) offering a "transmission fluid flush". What they do is hook up a machine and as the old fluid is extracted new fluid is added... sometimes under higher pressures, but not always.
A flush has advantages and disadvantages, the very act is surrounded by a lot of myth and at the same time some good anecdotal information. It is difficult to separate fact from fiction (or friction). I'll try.
When you drop the pan and replace a filter and replace the pan and then replace the fluid lost, you are replacing probably 1/3 of all fluid. It is rather like doing an oil change where you remove the filter and replace it, and drain a quart out of the pan and replace the plug and add 2 quarts to bring it back to full and calling THAT an oil change.
In the A4LD and 4R and 5R the convertor alone will hold a couple + quarts of ATF and cannot be drained unless you do a "flush" prodecure. (The convertor in the 4R70W has its own drain plug).
A "flush" in theory removes and replaces ALL fluid. It can be done with a machine at a garage, or in fact you can do sort of an "engine assisted" flush at home. [link coming].
Ok so the good news was in doing a flush that you replaced ALL the fluid. But unless you drop the pan, the filter didn't get changed. Maybe not a big deal, as filters often have a long life in a healthy transmission, but it is an issue to consider - or follow up with a pan drop and a filter change too.
Ok you ask, so what MIGHT be bad about a flush? Well ATF has a fair amount of detergent in it to keep stuff in suspension. If your transmission had never seen a fluid change in say 100,000 miles a sudden slug of detergent might dislodge crud long rather happily caked in place.... with untoward results - usually in the valve body where tolerances are critical. This is where the truth and fiction game begins.
The general advice that most accept is that if you have a new Explorer, and will be doing regular fluid changes, do flushes. If you have a high mileage transmission that has not enjoyed regular fluid changes in its lifetime, successive pan drops and replacements over a short period of time with maybe one or two filter changes might be a better idea.
Great science to support that? no. SOME anecdotal evidence? yes.
Q3. Are some transmission filters better than others? If so which ones?
A3. It is my opinion that the best filters are the dacron filters made by FRAM called Microfelt. See the following link. [link coming]
Q4. What is the difference between Mercon III and Mercon V beside price?Can I substitute MERCON III in place of Mercon V and save some $$?
A4. Mercon is the designation FORD gives to their requirements for ATF performance. While we tend to think of OIL as OIL.... Pennzoil 5-30 can be mixed with Quaker State 20-50 for example.... ATF is not all the same.
The simple answer is, if your transmission callsfor Mercon V... you cannot subsititute Mercon III. Mercon V has some special "friction qualities" that Mercon III does not. If the manual says use Mercon V, use V.
CAN you substitute Mercon V for Mercon III backwards? Yes, but Mercon V is way more expensive, so why?
Q5. My shop used Mercon III and an additive instead of Mercon V. Am I screwed?
A5. No, and kinda. Mercon III is not synthetic, at all. Synthetics have some advantages in terms of temperture stabilitity and longevity. Mercon V is "semi synthetic". (Not as good as full synthetic, but better han non-syn). It IS possible to add a special additive to make Mercon III mirror the friction qualities of Mercon V.
Is this an accepted practice? Yes. Is it safe? yes. Is this as good as using Mercon V to start with? No.
If you have a transmission using Mercon V (basically anything 96-97 on) and you are going to have the fuild replaced... ask if they will use native Mercon V or just Mercon III with an additive. Mercon V is the better choice.
There was a thread a while ago about Merc III verus Merc V... hee it is:
http://www.explorerforum.com/forums/showthread.php?t=73415&highlight=Mercon
Q5. OMG I accidentally mixed a quart of Merc III into my Merc V tranny. Am I in serious trouble?
A5. No. relax. The main difference between III and V is in two things. V is a mixture of synthetic oils and naturally occurring oils. Is syn better?yeah. Is semi syn better,? half yeah. Merc V has friction additives lacking in III. Is a 10% dilution factor gonna matter? no, not much.
The base stocks of ATF, like the base stock of oils, are interchangeable. Mix and match.
No it will not gel, not it will not thin, no it will not cause a spontaneous fire. And no one will die. RELAX.
Q6. Is it dangerous to overfill my transmission? Will it blow seals?
A6. An overfill, though not a good practice, will not cause internal damage to your transmission. If it was horribly overfilled by several quarts, the aeration of the fluid caused by parts rotating through it would not be a good thing, but would be unlikely to result in any lasting harm. The pump pressures do not change based on the fluid levels once they are adequate to maintain a level the pump can suction from. So you do not need to worry about higher pressures because of an overfill. Seals will not be blown out. Now seals that normally are above the fluid level, if submerged, may leak fluid, but that will stop once the fluid level is returned to proper levels.
Q7. I just dropped my pan and found this odd plastic plug in it (may have an O ring on it). WHAT IS IT ??
A7. Relax. At the factory they plug the fill tube with these and once they assemble the vehicle the plug gets pushed into the pan when they fill the tranny. NORMAL. (Breathe..... in... out.... yer ok.). Normal.
Ok this is it for now, much more to come. Stay tuned
So, specific inquiries below will be answered in the top thread and eventually we will hopefully have a comprehensive diagnosis thread here by tranny type is the plan. For now A4LD, 4R44/4R55 and 5R55 as well as 4R70W. More or less Explorers through 2002. Save a lot of answering similar Q's over and over.
A4LD COMMON PROBLEMS
Q1. I have a delayed engagement into reverse (sometimes also into drive). Why is this and how can I fix it?
A. In the A4LD the reverse band is used to engage both reverse and 1st gear. The servo that engages it has a seal prone to leakage, and it also has a rather large volume that needs to be filled and pressurized.
More often that not this is the culprit. Sometimes a leaky seal, sometimes a slow fill because of VB issues. About 50% of the people will find a fix in replacing the seals on the low/reverse servo with either a "double lip" upgrade, or a "D ring" seal kit. Both are cheap (under $5) but you have to drop the pan and valve body to get to it.
Good news? If you can live with it, it isn't doing any harm, just be patient before you goose it.
Q2. I get a loud "klunk" when I shift into reverse. Is this serious? What causes this?"
A2. Generally the "klunk" you hear is caused by worn U joints. The delay in the application of the low/reverse band can cause a sudden engagement, which causes the slack in the U-Joints to be taken up suddenly ..producing that noise. Dangerous? Serious? Hmmmm. Not really. Though the continual "hammering" of the bad joint will only make it worse. Might want to look at those joints, but life threatening? no. Relax.
Q3. I am lacking the 4th gear shift into OD. (The so called 3-4 shift)
A3. In the A4LD, the shift from 3rd to 4th (or the so called 3-4 shift) is controlled by a solenoid. In the majority of cases wherein there is a 3-4 shift lacking, either the solenoid has problems, the wiring to it has a probem, or a screen on some models may be plugged up. Checking the wiring and for voltage at the main feed wire to the solenoids is a first place to check. Many times lack of 3-4 will also have a lack of Torque convertor lockup too. This can add heat to the trans, and the common lack of 3-4 and TCC lockup usually is a good sign of an electrical issue, as neither solenoid is operating correctly. Often this issue may relate to the wiring harness to the PCM (computer). [Brooklyn Bay adds the following good observation: The PCM takes sensor inputs from various places, such as the Vehicle speed sensor, Brake On/Off switch, and Throttle position sensor to calculate when to apply a ground signal to the A4LD's solenoids to apply or not, or in the case of the Torque convertor clutch to lock, and unlock. Often, there could be a driveability problem due to one of these solenoids because of a bad input to the PCM from one of these sensors, and it might be mistaken for a solenoid problem when in fact it is not.]
Q4. I am going through ATF every with no apparent leaks. The transmission pan and rear seal is dry. The front seal appears to be dry. The radiator does not appear to have trans fluid in it either. The driveway is clean under the vehicle. Please help!
A4. The modulator on the A4LD can develop a tear or vacuum leak, and the fluid can be sucked into the engine. While logic would suggest it would be burned as part of the intake gases, it does show up as an overfill in the engine oil area. You can check for this by pulling a vacuum hose from the modulator and looking for ATF in the hose, but if this is your symptom, odds are about 100% you have a bad modulator. It needs to be replaced. It is on the passenger side behind the heat shield with a hose going to it.
4R44E/4R55E/5R55E COMMON PROBLEMS
Q1. My 4R/5R is starting to display an OD light that is flashing, and the shifts are sometimes late, or "soft".
A1. These transmissions use an electronic pressure control (regulator) solenoid (EPC) that works hard to maintain a contant pressure as commanded by the computer. It seems these have a useful life of 65,000 miles on the low side and about 150,000 miles on the high side. In addition, these transmissions were prone to blowing out main control (valve body) gaskets. FORD came out with a technical service bulletin (tsb) on these issues and there is a kit that modifies the VB and changes the separator plate and gaskets. I recommend whenever there is this issue to change out the EPC. It costs about $115. The FORD mods are about $30. This is a good time to upgrade the Valve body too. (See separate Q on this below).
Q2. I have a 5R55E transmission in my late 90's Explorer. I am strating to notice some shifting issues in the shifts between 1-2 and 2-3 ... kind of soft or dealyed and the RPM's will increase a little until the next gear engages. Is this serious? Is there something I should or could do to fix this?
A2. While, in fairness, there can be multiple possible causes for these symptoms, in general a majority are related to either leaking valve body (Main control) gaskets, or an Electronic Pressure Control Solenoid that is getting tired. When I hear of this problem, I generally refer folks to the 5R55E Valve Body Rebuild Diary here in the stickies, and also recommend a "shift kit".
What is a shift kit?
A Shift kit is an aftermarket engineering attempt to fix deficiencies in the original design. In many cases the actual manufacturer will pick up on some of these fixes and incorporate their own in later versions of the design. Overall, the 5R55E is a transmission with weaknesses in the Valve Body that shift kits address nicely. I recommend that if you ever have a need to remove the transmission valve body you have a shift kit installed. I think it will improve the life of your transmission.
GENERAL QUESTIONS
Q1. How often should I change my transmission fluid?
A1. The general answer is one of those "it depends" kind of answers. Remember the manufacturer only has to warranty drivetrain for a finite period. They will give a long interval, and then cover their a**es by saying "In Heavy Duty Applications... blah blah blah.."
One school says change it every 15,000 - 20,000 miles. Another says maybe every 30,000 to 40,000 unless you tow or tend to offroad or use big tires.
If you use yours on streets and highways and do no towing, I think a change every 30,000 to 40,000 miles is fine. Add towing and I am back to 15,000 to 20,000 miles.
Automatic transmission fluid is a rather unique product. The additive properties get destroyed by heat and age. They are important to help keep your transmission from slipping, and at the same time lubricate necessary parts. See how odd that sounds? Did you know that ATF used whale oil as a component part until harvesting whales was banned by international treaty?
Q2. Should I have a "fluid flush"?
A2. More and more we see places (like Jiffy Lube etc) offering a "transmission fluid flush". What they do is hook up a machine and as the old fluid is extracted new fluid is added... sometimes under higher pressures, but not always.
A flush has advantages and disadvantages, the very act is surrounded by a lot of myth and at the same time some good anecdotal information. It is difficult to separate fact from fiction (or friction). I'll try.
When you drop the pan and replace a filter and replace the pan and then replace the fluid lost, you are replacing probably 1/3 of all fluid. It is rather like doing an oil change where you remove the filter and replace it, and drain a quart out of the pan and replace the plug and add 2 quarts to bring it back to full and calling THAT an oil change.
In the A4LD and 4R and 5R the convertor alone will hold a couple + quarts of ATF and cannot be drained unless you do a "flush" prodecure. (The convertor in the 4R70W has its own drain plug).
A "flush" in theory removes and replaces ALL fluid. It can be done with a machine at a garage, or in fact you can do sort of an "engine assisted" flush at home. [link coming].
Ok so the good news was in doing a flush that you replaced ALL the fluid. But unless you drop the pan, the filter didn't get changed. Maybe not a big deal, as filters often have a long life in a healthy transmission, but it is an issue to consider - or follow up with a pan drop and a filter change too.
Ok you ask, so what MIGHT be bad about a flush? Well ATF has a fair amount of detergent in it to keep stuff in suspension. If your transmission had never seen a fluid change in say 100,000 miles a sudden slug of detergent might dislodge crud long rather happily caked in place.... with untoward results - usually in the valve body where tolerances are critical. This is where the truth and fiction game begins.
The general advice that most accept is that if you have a new Explorer, and will be doing regular fluid changes, do flushes. If you have a high mileage transmission that has not enjoyed regular fluid changes in its lifetime, successive pan drops and replacements over a short period of time with maybe one or two filter changes might be a better idea.
Great science to support that? no. SOME anecdotal evidence? yes.
Q3. Are some transmission filters better than others? If so which ones?
A3. It is my opinion that the best filters are the dacron filters made by FRAM called Microfelt. See the following link. [link coming]
Q4. What is the difference between Mercon III and Mercon V beside price?Can I substitute MERCON III in place of Mercon V and save some $$?
A4. Mercon is the designation FORD gives to their requirements for ATF performance. While we tend to think of OIL as OIL.... Pennzoil 5-30 can be mixed with Quaker State 20-50 for example.... ATF is not all the same.
The simple answer is, if your transmission callsfor Mercon V... you cannot subsititute Mercon III. Mercon V has some special "friction qualities" that Mercon III does not. If the manual says use Mercon V, use V.
CAN you substitute Mercon V for Mercon III backwards? Yes, but Mercon V is way more expensive, so why?
Q5. My shop used Mercon III and an additive instead of Mercon V. Am I screwed?
A5. No, and kinda. Mercon III is not synthetic, at all. Synthetics have some advantages in terms of temperture stabilitity and longevity. Mercon V is "semi synthetic". (Not as good as full synthetic, but better han non-syn). It IS possible to add a special additive to make Mercon III mirror the friction qualities of Mercon V.
Is this an accepted practice? Yes. Is it safe? yes. Is this as good as using Mercon V to start with? No.
If you have a transmission using Mercon V (basically anything 96-97 on) and you are going to have the fuild replaced... ask if they will use native Mercon V or just Mercon III with an additive. Mercon V is the better choice.
There was a thread a while ago about Merc III verus Merc V... hee it is:
http://www.explorerforum.com/forums/showthread.php?t=73415&highlight=Mercon
Q5. OMG I accidentally mixed a quart of Merc III into my Merc V tranny. Am I in serious trouble?
A5. No. relax. The main difference between III and V is in two things. V is a mixture of synthetic oils and naturally occurring oils. Is syn better?yeah. Is semi syn better,? half yeah. Merc V has friction additives lacking in III. Is a 10% dilution factor gonna matter? no, not much.
The base stocks of ATF, like the base stock of oils, are interchangeable. Mix and match.
No it will not gel, not it will not thin, no it will not cause a spontaneous fire. And no one will die. RELAX.
Q6. Is it dangerous to overfill my transmission? Will it blow seals?
A6. An overfill, though not a good practice, will not cause internal damage to your transmission. If it was horribly overfilled by several quarts, the aeration of the fluid caused by parts rotating through it would not be a good thing, but would be unlikely to result in any lasting harm. The pump pressures do not change based on the fluid levels once they are adequate to maintain a level the pump can suction from. So you do not need to worry about higher pressures because of an overfill. Seals will not be blown out. Now seals that normally are above the fluid level, if submerged, may leak fluid, but that will stop once the fluid level is returned to proper levels.
Q7. I just dropped my pan and found this odd plastic plug in it (may have an O ring on it). WHAT IS IT ??
A7. Relax. At the factory they plug the fill tube with these and once they assemble the vehicle the plug gets pushed into the pan when they fill the tranny. NORMAL. (Breathe..... in... out.... yer ok.). Normal.
Ok this is it for now, much more to come. Stay tuned
