4R70W shudder

[JoshT]

So automagic transmissions are out of my wheelhouse. I understad the concept at a very high level, but for the most part it's just magic. I don't really even know where to begin on troubleshooting transmission problems or sometimes evenif a problem is caused by the transmission.

What I've got is a 2000 Explorer 5.0L AWD drivetrain swapped into my 99 Ranger. Engine is fresh rebuilt, solid, tuned, and appears to be sorted. I do not believe that the issue started with the fresh engine, but didn't drive it much before the fresh engine to have a reference point. The transmission is original 180K+ mile Explorer AWD 4R70W. Only things changed on trans are new fluid and filter with the swap.

What I'm experienceing I can best relate to a manual transmission to describe. You know when driving a manual if you have the transmission in too high of gear for the speeds it'll buck or shudder. That's kind of what this feels like, but fairly light. Most noticable conditions are at 40-45 MPH on flat level ground with just enough throttle applied to maintain speed. If you open throttle to acellerate any it goes away, if you let off throttle it goes away. At this speed if you turn off OD it also goes away.

Happens at some other speeds too under same conditions, but that 40-45 range is most noticable.

I suppose it's lugging the engine. In a manual trans I'd downshift, but an automatic isn't supposed to require manually downshifting (or tuning off OD). I'm fairly sure that the culprit is something to do with transmission, whether it is something worn out, or shift points need adjusting in the tune. I have no idea where to begin on diagnosing and fixing.

I'd love to just say no driving at those speeds, a Sammy Hagar solution. Unfortunately given speed limits and places I regularly drive, that isn't an option. I'm just not sure how to advance on diagnosing and fixing.

FWIW, a shift kit (or J-mod) is in the plans for the future, but don't want to invest that into this transmission if I'll be replacing/rebuilding it in short order. Not to mention if there is a non-valvebody related problem, those modifications would likely acellerate the need for repalcement. On the flip side, if it is valvebody related, the shift kit modifications and reseal may fix it getting more life out of this transmission.

 

[rusty ol ranger]

This is a common issue on the crown vics. My 99 would do it occiasionally.

It seems like i remember reading something about the lockup solenoid getting "confused" because of something funky with a speed sensor or trans control computer.

IIRC...its been years since i looked into it

 

[Snoranger]

The last time I saw a problem with a Ford trans that had a mid speed shudder while cruising it was a ‘94 E150 with an E4OD. The problem was someone did a fluid change and used Mercon 3 instead of Mercon 5. I had to drain the pan and the converter and refill it Mercon 5. Problem solved… what fluid did you use?

 

[JoshT]

This is a common issue on the crown vics. My 99 would do it occiasionally.

It seems like i remember reading something about the lockup solenoid getting "confused" because of something funky with a speed sensor or trans control computer.

I could imagine the symptom being a "confused" solenoid. I can not figure how it would be tied to a speed sensor on this. There is no speed sensor in the transmission, only in the rear axle. That speed sensor does not report to the PCM and PCM does not appear to use it at all. It goes to the ABS computer and is used by that, the speedometer, and the cruise control. The PCM/TCU has no information for axle gear ratio, so the speed sensor signal would be about useless to it.

Not discounting it as a possibility, just spitballing and not seeing how that sticks.

The last time I saw a problem with a Ford trans that had a mid speed shudder while cruising it was a ‘94 E150 with an E4OD. The problem was someone did a fluid change and used Mercon 3 instead of Mercon 5. I had to drain the pan and the converter and refill it Mercon 5. Problem solved… what fluid did you use?

Valvoline Multi-Vehicle Full Synthetic ATF. Here's the compatability listing from the product information sheet and Mercon V is on there.

Based on my studying, it had been used successfully by a lot of people in the 4R70W. In addition, with recommendation, I added a bottle of the Lubeguard Synthetic ATF Protectant which is also supposed to help with high mileage transmissions.

 

[rusty ol ranger]

I could imagine the symptom being a "confused" solenoid. I can not figure how it would be tied to a speed sensor on this. There is no speed sensor in the transmission, only in the rear axle. That speed sensor does not report to the PCM and PCM does not appear to use it at all. It goes to the ABS computer and is used by that, the speedometer, and the cruise control. The PCM/TCU has no information for axle gear ratio, so the speed sensor signal would be about useless to it.

Not discounting it as a possibility, just spitballing and not seeing how that sticks.




Valvoline Multi-Vehicle Full Synthetic ATF. Here's the compatability listing from the product information sheet and Mercon V is on there.

View attachment 125279

Based on my studying, it had been used successfully by a lot of people in the 4R70W. In addition, with recommendation, I added a bottle of the Lubeguard Synthetic ATF Protectant which is also supposed to help with high mileage transmissions.

Youre sure the trans dont get info from the speed sensor?

When the rear axle mounted speed sensor went on my 97 F250 i did lose the speedo, but it also would not shift out of first unless i did it manually and then it shifted so hard it barked the rear tires. Thats an E4OD though.

Like i said i got rid of my vic in 08 so its been years since i looked into it lol. But cruising/searching the vic forums might help ya out. For whatever reason it seemed to be more of an issue on panthers....maybe cause of the 2.75 rear they notice it more? I dont know