Changed my PTU fluid
#11
08-04-2010, 08:49 AM
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Re: Changed my PTU fluid
Isn't it pretty well known that the Ford PTU isn't robust enough for even normal use..??
Heat builds in the PTU, boils the lubricating (and COOLING) oil, eventually no oil left the PTU fails. That's why the very same PTU in the Mazda CX-7 has engine coolant for cooling.
Makes me wonder how robust the PTU is in the new F/awd Explorer, same one..??
Given the apparent PTU/PTO failure rate I would advise everyone to pull the fuse during the summer months and only have it installed during wintertime. Or add a toggle switch to enable rear drive only when conditions warrant.
Heat builds in the PTU, boils the lubricating (and COOLING) oil, eventually no oil left the PTU fails. That's why the very same PTU in the Mazda CX-7 has engine coolant for cooling.
Makes me wonder how robust the PTU is in the new F/awd Explorer, same one..??
Given the apparent PTU/PTO failure rate I would advise everyone to pull the fuse during the summer months and only have it installed during wintertime. Or add a toggle switch to enable rear drive only when conditions warrant.
Last edited by wwest; 08-04-2010 at 08:52 AM.
#12
08-04-2010, 11:06 AM
Re: Changed my PTU fluid
Isn't it pretty well known that the Ford PTU isn't robust enough for even normal use..??
Heat builds in the PTU, boils the lubricating (and COOLING) oil, eventually no oil left the PTU fails. That's why the very same PTU in the Mazda CX-7 has engine coolant for cooling.
Makes me wonder how robust the PTU is in the new F/awd Explorer, same one..??
Given the apparent PTU/PTO failure rate I would advise everyone to pull the fuse during the summer months and only have it installed during wintertime. Or add a toggle switch to enable rear drive only when conditions warrant.
Heat builds in the PTU, boils the lubricating (and COOLING) oil, eventually no oil left the PTU fails. That's why the very same PTU in the Mazda CX-7 has engine coolant for cooling.
Makes me wonder how robust the PTU is in the new F/awd Explorer, same one..??
Given the apparent PTU/PTO failure rate I would advise everyone to pull the fuse during the summer months and only have it installed during wintertime. Or add a toggle switch to enable rear drive only when conditions warrant.
Pulling the 4WD fuse would remove the PTU load but not the constant rotation.
#13
08-04-2010, 12:28 PM
Re: Changed my PTU fluid
GaryG
#14
08-04-2010, 12:34 PM
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Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Changed my PTU fluid
What PTU in the new Explorer? What transaxle? Hope they aren't going to use the problematic 6F35? They should at least use the 6F50 as in the Edge or the 6F55 used in the Taurus SHO!
It probably doesn't really matter as long as they insist on a high coupling level to the rear even while turning. Bad enough to couple in the rear drive on a highly tractive surface to more evenly distribute the engine torque during straight-line acceleration but while turning??
Catch 22, not enough or no coupling and you have a simple, and DANGEROUS FWD, use the coupling in turns and that results in even more heating due to tire scrubbing and/or driveline windup.
Or Ford could admit to the design flaw and provide engine coolant flow to cool the PTO/PTU as Mazda is doing.
Pulling the 4WD fuse would remove the PTU load but not the constant rotation.
It probably doesn't really matter as long as they insist on a high coupling level to the rear even while turning. Bad enough to couple in the rear drive on a highly tractive surface to more evenly distribute the engine torque during straight-line acceleration but while turning??
Catch 22, not enough or no coupling and you have a simple, and DANGEROUS FWD, use the coupling in turns and that results in even more heating due to tire scrubbing and/or driveline windup.
Or Ford could admit to the design flaw and provide engine coolant flow to cool the PTO/PTU as Mazda is doing.
Pulling the 4WD fuse would remove the PTU load but not the constant rotation.
An ideal drive system using this "new" electrohydraulic clutch coupling would be a R/awd system. "Hard", constant coupling to the rear and incrementally lower coupling to the front as lateral/stearing forces build up. But you can't do that with a CHEAPLY built base FWD vehicle.
Last edited by wwest; 08-04-2010 at 12:40 PM.
#15
08-04-2010, 12:49 PM
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Join Date: Sep 2006
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Re: Changed my PTU fluid
NOT...!!
Were I in your shoes I would stick with the old Explorer until the Toyota 4runner has a DFI engine, a 6(9) speed transmission, and a R/awd system using this new electrohydraulic clutch variable torque coupling technique to dynamically vary the torque coupling to the front wheels in accordance with lateral/turning forces.
#16
08-04-2010, 07:40 PM
Re: Changed my PTU fluid
I have no idea what that is and of course it's too early for any manuals to appear in the online source. I haven't heard of a new transmission, so it must be outsourced for who knows where?
#17
08-06-2010, 05:11 AM
Re: Changed my PTU fluid
I'm not sure if anyone is interested but here is the update to my delima. The short version is that Ford honored their warranty and replaced the PTU at their cost along with changing the transmission fluid for free (which must have to be done to replace the PTU).
With the new PTU, what I've noticed is braking power is restored. I wonder if it is because the PTU and rear wheels actually do turn the generator in order to slow down (there is a TSB that states the rear brakes wear out twice as fast as the front brakes because the front tires are used to recharge the battery and the rear brakes are applied to stablize the vehicle) or because when my PTU was failing, a sensor was seeing more drag on the rear wheels so it didn't engage the rear brakes as much. Does anyone have any thoughts on this? I set an x-gage to monitor rear wheel % but it doesn't go negative so I assume it is the latter of the two.
I thought about removing my scangage when taking my MMH in for service but I left them in there. I always wander out while my car is being serviced and the service tech always asks me about it and what it does and it gives us something to talk about. I figure at the very least the conversation changes me from a faceless customer to a person, from the perspective of the service tech.
WWest - Will pulling the fuse cause diagnostic codes to pop up? I'll try it this morning as I just got my MMH back last night. My only concern is my question above about braking. If it turns out that in 4wd/AWD hybrids that the rear wheels also contribute to the regen braking, will that decrease braking power?
What I do know is that in the 4 years that I've owned my MMH, I've avoided hitting 3 deer (fastest was 65 mph) by braking rather hard and swerving. The control is incredible. In my other cars when I would perform the same maneuver, I could either brake hard or swerve. Trying both would cause my front tires to lock up and I would go straight no matter how I turned the wheel.
I'll experiment and see if removing the fuse reduces control. If it does, this may be my last post and I wish you all the best of luck both now and in the future with your vehicles. It was a pleasure enchanging ideas and solutions with ya'll.
If it doesn't, I'll post any results here.
With the new PTU, what I've noticed is braking power is restored. I wonder if it is because the PTU and rear wheels actually do turn the generator in order to slow down (there is a TSB that states the rear brakes wear out twice as fast as the front brakes because the front tires are used to recharge the battery and the rear brakes are applied to stablize the vehicle) or because when my PTU was failing, a sensor was seeing more drag on the rear wheels so it didn't engage the rear brakes as much. Does anyone have any thoughts on this? I set an x-gage to monitor rear wheel % but it doesn't go negative so I assume it is the latter of the two.
I thought about removing my scangage when taking my MMH in for service but I left them in there. I always wander out while my car is being serviced and the service tech always asks me about it and what it does and it gives us something to talk about. I figure at the very least the conversation changes me from a faceless customer to a person, from the perspective of the service tech.
WWest - Will pulling the fuse cause diagnostic codes to pop up? I'll try it this morning as I just got my MMH back last night. My only concern is my question above about braking. If it turns out that in 4wd/AWD hybrids that the rear wheels also contribute to the regen braking, will that decrease braking power?
What I do know is that in the 4 years that I've owned my MMH, I've avoided hitting 3 deer (fastest was 65 mph) by braking rather hard and swerving. The control is incredible. In my other cars when I would perform the same maneuver, I could either brake hard or swerve. Trying both would cause my front tires to lock up and I would go straight no matter how I turned the wheel.
I'll experiment and see if removing the fuse reduces control. If it does, this may be my last post and I wish you all the best of luck both now and in the future with your vehicles. It was a pleasure enchanging ideas and solutions with ya'll.
If it doesn't, I'll post any results here.
Last edited by crabby_bob; 08-06-2010 at 05:14 AM.
#18
08-06-2010, 05:36 AM
Re: Changed my PTU fluid
There's rarely any rear wheel torque once you reach a constant speed under normal driving conditions. I have seen just a few percent on a long downhill slope. Before anybody says anything, I'm refering to a FE not FEH which could be different but I doubt it. You have a SG-II, so code it to read 4WD.
Yes, pulling the fuse will cause the "wrench" dash icon to come ON. No problem but if it wants to come ON for another reason, you won't know then!
Yes, pulling the fuse will cause the "wrench" dash icon to come ON. No problem but if it wants to come ON for another reason, you won't know then!
#19
08-06-2010, 09:38 AM
Ridiculously Active Enthusiast
Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Changed my PTU fluid
I'm not sure if anyone is interested but here is the update to my delima. The short version is that Ford honored their warranty and replaced the PTU at their cost along with changing the transmission fluid for free (which must have to be done to replace the PTU).
With the new PTU, what I've noticed is braking power is restored. I wonder if it is because the PTU and rear wheels actually do turn the generator in order to slow down
It would be extremely wise of the Ford engineers to couple in the rear driveline when braking is only being derived via regen, once frictional braking is brought into the mix it should be uncoupled.
(there is a TSB that states the rear brakes wear out twice as fast as the front brakes because the front tires are used to recharge the battery and the rear brakes are applied to stablize the vehicle) or because when my PTU was failing, a sensor was seeing more drag on the rear wheels so it didn't engage the rear brakes as much. Does anyone have any thoughts on this? I set an x-gage to monitor rear wheel % but it doesn't go negative so I assume it is the latter of the two.
IMMHO it is entirely possible that you now have a new firmware revision that automatically couples in the rear drive when ONLY regen braking is being used.
I thought about removing my scangage when taking my MMH in for service but I left them in there. I always wander out while my car is being serviced and the service tech always asks me about it and what it does and it gives us something to talk about. I figure at the very least the conversation changes me from a faceless customer to a person, from the perspective of the service tech.
WWest - Will pulling the fuse cause diagnostic codes to pop up?
Probably.
I'll try it this morning as I just got my MMH back last night. My only concern is my question above about braking. If it turns out that in 4wd/AWD hybrids that the rear wheels also contribute to the regen braking, will that decrease braking power?
Probably, but maybe not substantially so, the PURE FWD HSD systems do without. And remember that in any case you front brakes put out 70-80% of the overall braking effort.
What I do know is that in the 4 years that I've owned my MMH, I've avoided hitting 3 deer (fastest was 65 mph) by braking rather hard and swerving.
Braking HARD would likely mean 100% frictional braking.
The control is incredible. In my other cars when I would perform the same maneuver, I could either brake hard or swerve. Trying both would cause my front tires to lock up and I would go straight no matter how I turned the wheel.
With the advent of ABS (and VSC..??) this is not an issue. ABS is "there" so you the vehicle will react correctly to stearing inputs even under severe braking.
I'll experiment and see if removing the fuse reduces control. If it does, this may be my last post and I wish you all the best of luck both now and in the future with your vehicles. It was a pleasure enchanging ideas and solutions with ya'll.
You might consider leaving the fuse in place but adding a "summer use" relay that enables the rear clutch power when the brakes are being used.
If it doesn't, I'll post any results here.
With the new PTU, what I've noticed is braking power is restored. I wonder if it is because the PTU and rear wheels actually do turn the generator in order to slow down
It would be extremely wise of the Ford engineers to couple in the rear driveline when braking is only being derived via regen, once frictional braking is brought into the mix it should be uncoupled.
(there is a TSB that states the rear brakes wear out twice as fast as the front brakes because the front tires are used to recharge the battery and the rear brakes are applied to stablize the vehicle) or because when my PTU was failing, a sensor was seeing more drag on the rear wheels so it didn't engage the rear brakes as much. Does anyone have any thoughts on this? I set an x-gage to monitor rear wheel % but it doesn't go negative so I assume it is the latter of the two.
IMMHO it is entirely possible that you now have a new firmware revision that automatically couples in the rear drive when ONLY regen braking is being used.
I thought about removing my scangage when taking my MMH in for service but I left them in there. I always wander out while my car is being serviced and the service tech always asks me about it and what it does and it gives us something to talk about. I figure at the very least the conversation changes me from a faceless customer to a person, from the perspective of the service tech.
WWest - Will pulling the fuse cause diagnostic codes to pop up?
Probably.
I'll try it this morning as I just got my MMH back last night. My only concern is my question above about braking. If it turns out that in 4wd/AWD hybrids that the rear wheels also contribute to the regen braking, will that decrease braking power?
Probably, but maybe not substantially so, the PURE FWD HSD systems do without. And remember that in any case you front brakes put out 70-80% of the overall braking effort.
What I do know is that in the 4 years that I've owned my MMH, I've avoided hitting 3 deer (fastest was 65 mph) by braking rather hard and swerving.
Braking HARD would likely mean 100% frictional braking.
The control is incredible. In my other cars when I would perform the same maneuver, I could either brake hard or swerve. Trying both would cause my front tires to lock up and I would go straight no matter how I turned the wheel.
With the advent of ABS (and VSC..??) this is not an issue. ABS is "there" so you the vehicle will react correctly to stearing inputs even under severe braking.
I'll experiment and see if removing the fuse reduces control. If it does, this may be my last post and I wish you all the best of luck both now and in the future with your vehicles. It was a pleasure enchanging ideas and solutions with ya'll.
You might consider leaving the fuse in place but adding a "summer use" relay that enables the rear clutch power when the brakes are being used.
If it doesn't, I'll post any results here.
#20
08-07-2010, 10:01 PM
Re: Changed my PTU fluid
Got rear ended, apparently only a minor hit. So I changed oils since I'm concerned about latent damage in the drive line.
65k miles on my 06 FEH.
Very little wear products in the PTU oil. Only 10 OZ of PTU gear oil came out even after an overnight drain. No apparent leakage from the vent. The transaxle oil is completely separate from the PTU oil so don't know why your dealer chose to do it.
With 65k miles and the OEM Brake pads still there, my pads show 6 mm thickness remaining on all pads (as measured by the dealer). I use the transaxle "L" position for braking very frequently and surmise that is why I don't see greater wear on the rear pads versus the front pads.
65k miles on my 06 FEH.
Very little wear products in the PTU oil. Only 10 OZ of PTU gear oil came out even after an overnight drain. No apparent leakage from the vent. The transaxle oil is completely separate from the PTU oil so don't know why your dealer chose to do it.
With 65k miles and the OEM Brake pads still there, my pads show 6 mm thickness remaining on all pads (as measured by the dealer). I use the transaxle "L" position for braking very frequently and surmise that is why I don't see greater wear on the rear pads versus the front pads.
