[Nails.Sch]

I've lurked here for about a year, but this is my first post. I replaced CVs, struts/shocks, and brakes, fixed the dash lights, replaced the oil pan gasket, and some other stuff I don't remember right now.

A couple days ago, I was merrily cruising along I-40 about 50m east of Oklahoma City, literally thinking about how swell my Taurus is for touring. On a level section of highway, without shudder, jolt or crunch, the engine suddenly red-lined and the car started to coast. I tapped the brakes to kill the CC and coasted to the side of the road.

What could it be?

Restarted the car, and every gear is like neutral except Park, which is still park (I bumped the car to see if it would roll). No oily mess under the car, plenty of trans fluid, not burned. No OBD errors. After some light reading in Chilton, I checked some fuses including for PCM -- all good.

What could it be?

It's still on the U-Haul car dolly and it's raining, so I haven't even started really looking at it. But in earlier searches here, I remember seeing a lot of smack about torque converter spline failures. I'm just asking for two things now: 1) is there an easy way to rule this out before taking everything apart?; 2) I know how to search, but I'd appreciate someone pointing me to the best threads to get into this.

Thanks.

 

[MERCrunner]

Same thing happened to my '04 Sable DOHC this past Sept...except, I was driving in a residential area. Coasted to the side of the street and called the tow truck to come haul it to the JY. It had 281K miles and serious rust...so, doing any maintenance of this magnitude was not going to happen. I can't steer you in the direction of how to diagnose it...just came to the conclusion from what I'd read on here that is was most likely stripped TC splines. Good luck.

 

[Nails.Sch]

Thx.

[Edited to remove stupid stuff I thought at first]

 

[sheila]

Is the atf level the same with the eng. idling and off. Tranny needs dropped for TC r&r.

 

[Phoenix15A]

Are you absolutly sure your CV Axel didn't pop out? I had the identical thing happen to me, I was dreading the striped spline thing too, but for me it was a CV Axel I didn't fully seat, it kept popping out. It looked like it was in, but obviously wasn't. I finally had to take a sledgehammer and a block of wood to beat the Axel in. Carefully. You have to push in on the axel while you carefully thump it, otherwise you can ruin the joint. If you still can't get it to seat, I've had axels come from the local parts store missing their snap ring on the end. Might be worth a look.

 

[Nails.Sch]

Continued thanks.

Is the atf level the same with the eng. idling and off. Tranny needs dropped for TC r&r.

On the shoulder of the freeway, I just glanced that the level was on the stick and wasn't burnt. I assume the TC is still full of fluid like normal, just no longer attached to the crankshaft.

Are you absolutly sure your CV Axel didn't pop out? I had the identical thing happen to me, I was dreading the striped spline thing too, but for me it was a CV Axel I didn't fully seat, it kept popping out. It looked like it was in, but obviously wasn't. I finally had to take a sledgehammer and a block of wood to beat the Axel in. Carefully. You have to push in on the axel while you carefully thump it, otherwise you can ruin the joint. If you still can't get it to seat, I've had axels come from the local parts store missing their snap ring on the end. Might be worth a look.

I got them to seat, snap rings installed, with some persuasion. I didn't hear any funny noises -- a think dislocated axle would make a whole lot of flop and noise. The axles appeared to be in place just fine.

[Edited to remove stupid stuff I thought at first]

Has anyone replaced the TC at home? It doesn't really sound like a huge fkn PITA. Just a garden-variety fkn PITA. But I'll finally need to spring for a trans jack.

 

[ice445]

Continued thanks.



On the shoulder of the freeway, I just glanced that the level was on the stick and wasn't burnt. I assume the TC is still full of fluid like normal, just no longer attached to the crankshaft.



I got them to seat, snap rings installed, with some persuasion. I didn't hear any funny noises -- a think dislocated axle would make a whole lot of flop and noise. The axles appeared to be in place just fine.

I believe trying to turn the TC should confirm or not; and I'll be prepared to challenge it with a pretty stout effort. But the car didn't even try to move in gear, so the TC might not be very stuck, splines or not. I should know more late tomorrow.

Has anyone replaced the TC at home? It doesn't really sound like a huge fkn PITA. Just a garden-variety fkn PITA. But I'll finally need to spring for a trans jack.

The converter strips on the pump shaft side usually which means the trans can't build any pressure. That's why you check if the level on the stick drops once it's running, since the pump running should lower the volume in the pan. If the level is still way up the stick then yeah, tq spline failure is likely.

 

[Architect]

Restarted the car, and every gear is like neutral except Park, which is still park (I bumped the car to see if it would roll). No oily mess under the car, plenty of trans fluid, not burned. No OBD errors. After some light reading in Chilton, I checked some fuses including for PCM -- all good.

You could check the connector of the TRS (Transmission Range Sensor) a.k.a. NSS (Neutral Safety Switch) and the 10-pin connector at the transmission. Perhaps the PCM thinks the transmission should be in N or its instruction to switch gears does not reach the transmission. I think that a scanner like Forscan can tell you which gear the PCM thinks the transmission is in.

 

[Steve83]

Has anyone replaced the TC at home?

Undoubtedly, someone has. But that's irrelevant since you don't know that ANY part needs to be changed yet. You haven't diagnosed the problem. What sheila & ice recommended is quick, easy, & free.

It doesn't really sound like a huge fkn PITA. Just a garden-variety fkn PITA. But I'll finally need to spring for a trans jack.

If you find nothing wrong with the TC or trans after buying the jack & pulling the trans out, your opinion may change on the level of PITA. Slow down, and diagnose first.

 

[sheila]

^+1. With eng. off, atf level will read overfull. With eng. idling/warm, atf should read lower in the safe crosshatch area on the dipstick. If atf level remains unchanged (overfull), with eng. on/off, you probably have TC or pump shaft problems.

 

[Nails.Sch]

Continued thanks for the low-PITA things to check.

I didn't mean to imply that I was going to rip it apart and start ordering tools and parts. I just now got the car off the dolly and into my shop, where I can let the ice melt and look at it more closely. (And return the U-Haul.)

I don't want to run it in there until warm, but I'll do what I can to compare the T fluid level running and not. Of course, it was high when I checked on the side of the freeway, car off. And I'll check that plug -- that would be sweet. And whatever else I can do to rule out the TC ... just like I said in my first post.

Hope to have an update late tomorrow. Really appreciate the good advice getting started.

 

[chartmaker]

Continued thanks for the low-PITA things to check.

I didn't mean to imply that I was going to rip it apart and start ordering tools and parts. I just now got the car off the dolly and into my shop, where I can let the ice melt and look at it more closely. (And return the U-Haul.)

I don't want to run it in there until warm, but I'll do what I can to compare the T fluid level running and not. Of course, it was high when I checked on the side of the freeway, car off. And I'll check that plug -- that would be sweet. And whatever else I can do to rule out the TC ... just like I said in my first post.

Hope to have an update late tomorrow. Really appreciate the good advice getting started.

I had to replace the flex plate on '03 DOHC. Shop had to drop the engine to do this. While it was apart I had them replace the TQ. '03 early build had significant fails of the female spline on the TQ.
However, I remember back in those days, those fails were in relatively low miles. Less than 70K. My car had ~180K at the time. After it went to the JY with 199K miles due to rust.
As to just which year builds had the "early" fail, I do not remember which years but do know early '03 was included. I have another '03 DOHC now and it is ~160K miles. No issues. (except front brake hoses).
-chart-

 

[Nails.Sch]

I also read about problematic TCs, and I'm sure my '02 was on that list. That's why I was thinking a bad TC right off the bat. I almost didn't buy the car for those reports. And alas ...

From what I read, I expect to drop the transaxle and subframe, supporting the engine with a beam across the strut towers (I think). I've swapped many transmissions, but all conventional rear-wheel drive. Fortunately, my new shop has an "oil-change" pit so I don't have to crawl around too much. And like I said, I recently turned many of these bolts anyway on other repairs.

Tomorrow afternoon I hope to check the t-fluid levels and go from there. Vamos a ver.

 

[Nails.Sch]

Okay, the tranny fluid drops about 3/4" in N or D (engine running) from where it is with the engine stopped in Park. But even running, it's more than an inch above full.

With the engine kinda warmed up, the RPMs dropped when I put it in D. But when I quickly checked inside the shop (engine not so warmed up but car more level) it didn't. Not sure that means anything.

I found the TRS, and everything seems fine just looking at it. Apparently hooked to the floor shifter right. I should be able to check that it has power, but Chilton is pretty worthless beyond that -- doesn't have a pin-out. Does anyone happen to know which fuse powers this TRS? I'll hit it with contact cleaner and plug it back in. I have no idea how to check this at the PCM.

Not too clear where to go from here.

Continued thanks.

 

[Steve83]

IDK if this is correct since I guessed on the engine VIN.

 

[Architect]

The power to the TRS is during starting on pin 10 (through fuse 37 underneath the dash). But since the engine starts properly, that works fine.

There is another fuse (#28 engine compartment) that powers the Transmission Shift Solenoids. You could check that. But I assume that one is fine as well because it is also used as the fuse of the heated oxygen sensors and the CEL will light up if that fuse is blown. See fuse-box.info Taurus 2002.

I don't know much about the transmission, but I would guess that if you clearly feel the transmission engage when you shift it into D, it is not the electronics. But you are absolutely sure once a scanner reports that the PCM says it is in D.

 

[Nails.Sch]

Thanks for the replies. I'm impressed by the expertise here.

As for the trans oil-drop test, I'm seeing my result as a split decision: some drop, but fluid level still high. I suspect that the pump partially works -- perhaps the splines are sheared off but there's still some friction.

Steve83, thanks for the pin-out. I'll at least confirm that the TR sensor is getting power (pin 10, as Architech identified below). If I can figure out the polarity, I'll confirm whether it sees Drive &etc.

Are you absolutly sure your CV Axel didn't pop out?

Both axles are properly engaged .

The power to the TRS is during starting on pin 10 (through fuse 37 underneath the dash). ... There is another fuse (#28 engine compartment) that powers the Transmission Shift Solenoids.

These fuses are good.

if you clearly feel the transmission engage when you shift it into D, it is not the electronics.

I did not clearly feel that. Except for one instance, I could run the floor shifter up and down without a response of any kind. I initially thought the shifter was disconnected but then checked that it really goes into Park.

My earlier comment about the RPMs dropping when I shifted into D was when I had the car outside, nose pointed slightly down, and the engine partially warm. I didn't notice it earlier; and I couldn't repeat it about a half-hour later (engine cooled down after using a come-along to get the car back into my shop).

But at the time I shifted it onto drive a few times, and the RPMs dropped each time. I also felt a slight nudge and initially thought I had accidentally fixed it -- fat chance. Maybe there's a certain window in the warm-up sequence that uses the shift position somehow. But I clearly don't understand this at all. (I'm not trying to be difficult, just calling 'em like I see 'em. )

But you are absolutely sure once a scanner reports that the PCM says it is in D.

I don't think my scanner can do that, but I'll look into it closer.

 

[Nails.Sch]

It's looking like I'm not really gonna know for sure whether the TC is bad without taking it out and looking at it. And if not that, then it's apparently a bad trans. So I think it's time to start wrenching.

I'll search again here, but from earlier searches I don't remember seeing this: did FoMoCo supersede this defective TC with a new PN that doesn't break every 80K?

 

[chartmaker]

It's looking like I'm not really gonna know for sure whether the TC is bad without taking it out and looking at it. And if not that, then it's apparently a bad trans. So I think it's time to start wrenching.

I'll search again here, but from earlier searches I don't remember seeing this: did FoMoCo supersede this defective TC with a new PN that doesn't break every 80K?

Likely just some late '02 and early '03. SOME. I had '03 DOHC at ~180K replace the TQ while it was out for new flex plate. Spline on old one look fine. "03 DOHC present, 155K and it is fine. Present '04 DOHC 163K and fine. Looks like those that are going to fail did so before higher miles. Else last life time.
-chart-

 

[Nails.Sch]

Continued thanks.

Okay, a batch of defective TCs; and all I need to do is buy a new stock TC and quit worrying about it.

Now to plan this heinous job.