GregH Posted October 17, 2009 Share Posted October 17, 2009 I'm coming in on the tail end of this repair - one of my coworkers who is a very talented tranny guy has one that bit him in the ass.. '10 milan, low miles. Transmission shudders hard - and I mean really hard - when torquing the engine up in the stall in reverse and drive. No codes. TSS signal jumps from 0rpm to 130rpm or so in a staccato fashion. This occurs when we hold the engine RPM between 1000 and 1500rpm. The whole engine jumps around in the engine compartment, and the exhaust bangs against the underside of the vehicle. Fluid is burned black. Remove, teardown and inspect - no metal, no worn clutches. Replace low/reverse components, torque convertor, and solenoid bdy. Set the correct calibration according to the number etched on the solenoid body. Reassemble, install and retest - problem solved. Return to customer, he has it 25 miles, and the problem happens again. Back into the shop, and the condition is identical. Here is where I enter into the picture. Scan for codes - gear 3 and 5 incorrect ratio, and SSB performance. Torque it up again, and TSS and OSS both jump when the transmission shudders. At one point, the OSS read 160rpm - vehicle was in the stall the whole time... We decide to take it out onto the road - gently, of course. While driving down the highway under low load, the PCM started to command random gears - even commanded first gear several times - VSS was holding steady at 60mph at the time... Thank goodness for the one way clutch in the torque convertor! Ok, so taking the performance of the transmission out on the road - specifically the commanded first gear at highway speed - I am thinking that the PCM is failing. It doesn't explain the shuddering in the stall when torquing, but if the PCM is freaking out it could be cauing this behavior... This behavior is similar to a torqueshift in a gasser I had a while back. Broken components in low/reverse, rebuild tranny, retest and once it was hot it started commanding first at highway speed. Made the rear tires skid and I almost swapped ends - PCM was causing it. The message boards on Ford are full of this type of complaint.. Some seem to have been repaired by replacing the transmission. But most have had more than one... I haven't seen anyone fix this with a PCM... Anyone else been here? Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 18, 2009 Share Posted October 18, 2009 Greg... that Milan has three possible transmissions accordng to the WSM... seeing the reference to gear ratios, I feel safe if discounting the CVT but that still leaves us with two... knowing which one may help.... OK... I think I've narrowed it down to the 6F35 and, hopefully, this will be my last rewrite.... Trans pressure while the concern is happening might help as well as the exact codes... I suspect that any shift solenoid codes you are getting will be symptomatic rather than causal - but at this point I would call that assumption "taking something for granted"... By this, I mean that the PCM hasn't seen a commanded change in rpm at one sensor or another (verify by comparing GEAR_RAT to TRAN_RAT) and is <assuming> that SSB <may> be stuck... TSS jumping would indicate internal slippage at one friction or another (how does stall speed compare to spec?).. a jumping OSS is adding confusion... I don't have much time working with the 6F35 and I can't say for sure where they are getting OSS... but for this to jump when the car is standing still??? Add that both of these sensors are hall effect and RFI shouldn't be a big deal... but don't discount charging system issues all the same. Your burnt fluid could indicate a trans/converter cooling issue as well. Since you are creating a stall condition, the converter is going to be hot anyway.... Adam had a 6F35 in an Escape the other day... burnt fluid... runaway on stall test.. the customer took it away?!?!?!? IIRC his LPC at idle was high or at the high end of the limit and his stall pressures were low... not tragically low but remarkably low... Normally, I like to have a real good idea of what I am looking for when I go into a transmission... we didn't have the opportunity to get real hard into scan tool diagnostics and I was nearing the thought that we may be looking for a needle in a haystack. Did your tech think to check the worm trails for flatness? Not a common thought, by any means, but when you don't see stuff.. sometimes your search needs to get more in depth... Quote Link to comment Share on other sites More sharing options...
Adam_Dodson Posted October 19, 2009 Share Posted October 19, 2009 yup that escape will be back on the hook real soon. hopefully in more then one peice Quote Link to comment Share on other sites More sharing options...
GregH Posted October 23, 2009 Author Share Posted October 23, 2009 The line pressures haven't been checked with a manual gauge yet. The worm trails were checked for flat, and there were no blown gaskets... On consensus from us four techs, the tech working the car disconnected the battery and allowed everything to reset. When he drove the car again, all the problems were gone. Right now, the car is sitting in my driveway, 60 miles from work. Last night, the car performed beautifully both on the highway and in town. Even the slow stop and go traffic that was trying to get around the local high school's homecoming parade. We'll see how it does this morning when I go back to work. You know, we've been here before with other modules. I can't count how many radios in F-150's failed to come on with the key on. after testing, and finding that the accessory delay relay is not energized, removing power from the IC briefly has fixed it. I've replaced a handful of clusters for this concern, and so far they have remained fixed... Some of the trucks that declined repair have needed the IC rebooted again when the problem reoccurs. We had an APIM that wouldn't supply 5V to the USB port. No communication with the APIM. Checked power and ground, ok. Cycle poer to the APIM, and everything goes back to working. And just yesterday, I read an SSM on a PDI for an Escape. It said that letting a trnsit, focus, escape, and others sit for more than 50 days without cranking the engine will result in a no crank, PATS lamp flashing, and no communication with the PCM. The fix? Remove the KAPWR fuse to the PCM for a moment to allow the PCM to reset. The cause? The internal key off timer has exceeded it's maximum count - locking up the PCM. There is software running all the time on all of these modules. As an amateur hardware and software designer, even I realize there are limits to what we can expect these designs to do. Software cannot run nonstop indefinately without encountering an error. Take your windows PC - how often do you reboot it? Even my cellphone - I have to cycle it's power once every two weeks or it will not play it's ringtone during an incoming call (the .mp3 file is corrupt before a reboot, and amazingly uncorrupts upon a reboot) Yeah, so on this Milan, I'm going to recommend a PCM... And hope that the new one is less glitchy... Quote Link to comment Share on other sites More sharing options...
GregH Posted October 29, 2009 Author Share Posted October 29, 2009 Well, the vehicle ran perfectly the other morning. We decided another round trip to the house was in order, so last night I drove it again. Took it back to work this morning, and had issues the whole way. I couldn't get more than 3/4 throttle on the road before the transmission started to jerk. Once I got to work, torquing the engine up in the stall saw the same result - the powertrain would jump so much I thought it was going to hop out of the engine compartment and take off down the street... Data - GEAR_RAT showed commanded first gear. TRANS_RAT showed the transmission holding first gear until the jumping occurs. Then TRANS_RAT is all over the place. TSS and OSS jump - TSS in time with the jerking, and OSS would spike a little here and there. Then the wrench light comes on, TPMS light comes on, and the instrument cluster starts showing a speed - varied with engine RPM, but went from 5mph to 30mph. Place the gear selector in all the other ranges, and the speedometer still reads a speed. Switch over to other modules looking at VSS. PCM shows 0, ABS wheel speed PIDS are all 0, ACM and IC VSS PIDS show what the speedometer is reading. Codes in the PCM were P0720, P0722. Codes in other modules were for loss of communication with PCM and IC. Clear codes, disconnect battery, let it all reset again. Tried it after an hour, and I got the same behavior - jumping under load, TRANS_RAT and TSS spiking in time with the jump. Speedometer showing 20-30mph. We went on to load test powers and grounds to PCM - no problems found. We ran out of time before we could start disconencting the alternator and swapping coils in pursuit of a possible RF problem... Add to that pile a 6.0L in an E-series transit bus - got the engine out early last week to fix a compression issue. Told the service manager that we need the adapters for the engine stand to mount up the motor. Guess what? Snap-on man screwed us - he couldn't get them after giving us the runaround for a few days. Ordered them from online somewhere, and they came in this morning. They don't fit our engine stand! Send the adapters and a mating part of the stand to the local machine shop for modifications - they call back a few hours later and tell us they can't do it! So I call the local machine shop in the town I live in - no problems getting it done here. So I boxed 'em up and brought them home with me. Hopefully it won't take too long. We're already over a week past the original promised date, and they are a little antsy... Ahh, beer... Quote Link to comment Share on other sites More sharing options...
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