Ecoboost Performance Forum

Ecoboost Performance => Troubleshooting, Maintenance, TSB Articles => Troubleshooting => Topic started by: Gofspar on October 15, 2019, 02:21:22 PM

Title: Possible blown PTU and or RDU?
Post by: Gofspar on October 15, 2019, 02:21:22 PM
welp I think my RDU or my PTU is starting to give up, if I brake boost to 1800rpm then launch I get a violent shake around peak power at 4k from either behind me or right under me.

Does anyone have documentation on swapping out a PTU?
Title: Re: Possible blown PTU and or RDU?
Post by: SM105K on October 15, 2019, 02:27:40 PM
Quote from: Gofspar on October 15, 2019, 02:21:22 PM
welp I think my RDU or my PTU is starting to give up, if I bake boost once I hit around peak power at 4000rpm I get a violent shake from either behind me or right under me.

Does anyone have documentation on swapping out a PTU?

Is your PTU whining? 

Also, it could be transmission shudder or even wheel hop since you say it happens around peak power.  If you want, I can give you a second opinion because I am local.

The stock trans mounts are garbage as well.
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 15, 2019, 02:42:06 PM
Quote from: SM105K on October 15, 2019, 02:27:40 PM
Quote from: Gofspar on October 15, 2019, 02:21:22 PM
welp I think my RDU or my PTU is starting to give up, if I bake boost once I hit around peak power at 4000rpm I get a violent shake from either behind me or right under me.

Does anyone have documentation on swapping out a PTU?

Is your PTU whining? 

Also, it could be transmission shudder or even wheel hop since you say it happens around peak power.  If you want, I can give you a second opinion because I am local.

The stock trans mounts are garbage as well.

I don't hear any loud whining, before I did the swap to amsoil it had some whine but it went away after that.
It started happening after it was like 55 couple nights ago and I decided to go launch it, think the extra dense air put it on its knees.
Kinda feels like something is skipping a tooth.
As for trans mounts I have trans mounts done, stockers have been gone for couple weeks now.
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 15, 2019, 02:44:09 PM
Also it's extra bad if I go around a corner and apply some heavy throttle. All symptoms began after that hard launch on that cold night.
Title: Re: Possible blown PTU and or RDU?
Post by: SM105K on October 15, 2019, 02:55:14 PM
Quote from: Gofspar on October 15, 2019, 02:44:09 PM
Also it's extra bad if I go around a corner and apply some heavy throttle. All symptoms began after that hard launch on that cold night.

Interesting.....I do want to experience this.
Title: Re: Possible blown PTU and or RDU?
Post by: TopherSho on October 15, 2019, 10:30:34 PM
Quote from: Gofspar on October 15, 2019, 02:44:09 PM
Also it's extra bad if I go around a corner and apply some heavy throttle. All symptoms began after that hard launch on that cold night.

Ouchie,  unless you have changed the TQ converter 4000rpm is too high of a launch rpm on OEM converter\tranny.  Mine wont even launch @ 3000 rpm,  it disengages,  slips, feels like it looses power,  hits the rev limiter ... re-engages with a loud BAM! and then the tranny goes into some weird mode where the RDU is the only drive pushing the car and the tranny wont select a gear until it reboots.

Also check your tranny fluid level .. many stronger builds here on the forums wont hook up in 1st or on downshift until you add extra fluid above the hash. 



Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 15, 2019, 11:56:02 PM
Quote from: TopherSho on October 15, 2019, 10:30:34 PM
Quote from: Gofspar on October 15, 2019, 02:44:09 PM
Also it's extra bad if I go around a corner and apply some heavy throttle. All symptoms began after that hard launch on that cold night.

Ouchie,  unless you have changed the TQ converter 4000rpm is too high of a launch rpm on OEM converter\tranny.  Mine wont even launch @ 3000 rpm,  it disengages,  slips, feels like it looses power,  hits the rev limiter ... re-engages with a loud BAM! and then the tranny goes into some weird mode where the RDU is the only drive pushing the car and the tranny wont select a gear until it reboots.

Also check your tranny fluid level .. many stronger builds here on the forums wont hook up in 1st or on downshift until you add extra fluid above the hash.

running a quart heavy with Amsoil LVATF, pretty sure its the RDU because the PTU doesn't make any weird noise just cruising around and if I try to give a hard acceleration I hear a THUDTHUDTHUD from the rear and I blow the fronts off
I launch usually around 1800rpm.

this weekend I'll probably pull the fluid from the PTU, RDU and transmission and see which one has metal flakes lol.

Also a note, it still drives completely normal just putting around and carrying my ass to work.

Guess I wont be attending SCT this year, darn..
Title: Re: Possible blown PTU and or RDU?
Post by: SHOdded on October 16, 2019, 06:01:44 AM
Looks like too much power to the RDU, may have overpowered the clutch packs, even if for just that instant at launch.  Could have damaged the driveshaft in the process, if you feel vibration in the passenger cabin while driving.  I would check the trans fluid also, a quart additional seems too much, I thought a pint was recommended.

Traction control has a role to play while moving.  If sudden changes in throttle coincide with changes in direction, you can experience momentary power loss.

Most people will not BB higher than 2,500 rpm for a launch, tuned or untuned.  Were you in Neutral when you hit 4,000 rpm? 
Title: Re: Possible blown PTU and or RDU?
Post by: SM105K on October 16, 2019, 08:44:07 AM
I don't think he launched at 4K guys.  He said he launchred and at peak power is when he felt it.

The SHO wont let you launch at anything really over 2800 rpm.  Torque Source kills the car.  Ask me how I know....repeatedly.
Title: Re: Possible blown PTU and or RDU?
Post by: SHOdded on October 16, 2019, 10:02:30 AM
You can find instructions for Gen 5 SHOs here, courtesy of nickstewartroc
http://www.nicksmustangranch.com/Service_Manuals/2014/2014_Taurus/Service%20Manual.htm (http://www.nicksmustangranch.com/Service_Manuals/2014/2014_Taurus/Service%20Manual.htm)
Title: Re: Possible blown PTU and or RDU?
Post by: shoNoff on October 16, 2019, 02:55:41 PM
Remove the rear seat pad. If it's the RDU trust me you will hear it much better with that out. Takes like 5 mins to do. I've been through this myself already. Pretty simple fix for me I just found my local ford dealer and traded it in. Also I agree no way he launched at 4K rpm. Its completely impossible on a stock torque converter.
Title: Re: Possible blown PTU and or RDU?
Post by: SHOdded on October 16, 2019, 03:24:41 PM
I was thinking of a neutral drop situation lol.
Title: Re: Possible blown PTU and or RDU?
Post by: shoNoff on October 16, 2019, 06:36:04 PM
God I remember those days. My poor AOD's lol
Title: Re: Possible blown PTU and or RDU?
Post by: TopherSho on October 16, 2019, 08:34:40 PM
*whew* reading it left me with a impression of a 4k launch.. that would be horrific.   Since the shafts spin at all times and don't THUMP, and only engage on demand and then thump I agree that the packs are probably shot, mangled etc.   You can get a rdu to your door in 2-3 days and swap it with a good broad Jack and tools.   
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 16, 2019, 10:02:16 PM
rephrased some stuff in the OP, I launched at 1800RPM, not 4k.
dont think the converter or torque source will even let you do that lol.

Also I tried to see if It'd do it in any gear other than 1st and it seems to be confined to 1st which isn't a good sign.
Maybe im traveling too fast in 2nd for the RDU to hit the point where it shits out?
I'll do a 2nd roll tonight on my way home and see if the cold air will allow it to do it in 2nd.

Really hope its not a transmission issue.
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 17, 2019, 12:39:41 AM
k, cold air made it happen in 2nd.
guess im looking at the PTU or RDU.
Title: Re: Possible blown PTU and or RDU?
Post by: SHOdded on October 17, 2019, 03:58:23 AM
Have you checked tire pressures?  Sometimes that sets off the AWD system, if the psi is too low.  We have had one member report such an incident.
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 19, 2019, 09:21:42 PM
The 2010 MKS should have the same final drive as the 2.77's in my SHO, right?
Why is the axle identifier 4A and not 1A?

https://www.lkqonline.com/2010-Ford-Taurus-Sedan-Carrier-Assembly/-hFnmnncnDDcnDD/-i~202161063 (https://www.lkqonline.com/2010-Ford-Taurus-Sedan-Carrier-Assembly/-hFnmnncnDDcnDD/-i~202161063)
Title: Re: Possible blown PTU and or RDU?
Post by: Gofspar on October 23, 2019, 04:10:49 PM
Just got back from a buds shop, first we checked the diff by spinning the wheels independently and everything checked out ok. then we put the car in drive on the lift and the rear wheels slowly spun. ok, seems normal.

Then if we put some pressure holding the rear tires from spinning and the driveshaft stops spinning, so im looking at catastrophic failure of the PTU despite it not making any weird noise other than when I broke it and for when I would try to get on the throttle heavy from a dig, kinda sounded like teeth skipping on something.
Has anyone broke the shaft that connects the ptu to the transmission?

Should I just bite the bullet on a brand new PTU or where should I be looking to get one used?
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