Yet another transmission question...

[Dredwolf]

My wife's 2003 XLT with the K code V-6 has 217,000 miles on it. Trans was rebuilt by original owner at a little over 70K. The timing chains and tensioners were replaced last year, then had a head gasket leak this fall, tore it down to fix that, and one of the replaced timing chain tensioners failed at first crank, threw off the timing, and cost us three valves, etc. Repaired that mess, got it back on the road, but three weeks later, it would not move until the fluid warmed up. Fine, drop the pan, change fluid and filter. Now tonight, after 30 minutes on the interstate, we started getting what seems to be an occasional harsh shift 4th - 5th until slight power, but it feels to me like what happens with the auto 4x4 gets confused about where to send the power, if that makes sense. Nothing happens under hard acceleration, or steady pulls up a grade, or coasting, but if you are barely on the accelerator, above 40 Mph, it may happen once out of every three times.
No codes that my scanner picks up, and no OD light indications. The transmission shops in my area don't have great reputations, and most won't let me finish the symptoms before they are quoting a transmission rebuild. I don't mind spending $$ on this Explorer (it took us to Colorado and Utah, and tearing that motor down twice was not cheap), but I have had horrible experiences the few times I have ever involved a "professional" to work on any of my vehicles, and ended up re-doing all the work to fix the mess the "professional" made, even with his lifts, business cards, ASE signs, gigantic Snap-On toolboxes, etc, etc. I do a lot of my own work, and have rebuilt manual transmissions and several transfer cases, but I figure this automatic transmission is beyond my skills.
I have the ticket from the previous owner's "rebuild", but no mention of the servo bores being done. Are there other diagnostics I can do that you would suggest before I gamble $$ taking it to a shop?

 

[Dredwolf]

Well, I am trying to decide if I should be slightly amused that I have found a brand new problem, or hopeless because I found yet another problem.
I believe the transmission is the 5R55W. Digging through the paperwork we got when we bough the 3rd Gen from the previous owner, I found the repair order from the shop that did the rebuild, but no odometer reading, of course. But we have a date...04/20, we bough the SUV at 108K in September of that same year, so guessing the transmission got the rebuild before 90K.
Looks like the converter, Int & OD bands. solenoids, OD sprag, both servos, and OD planetary were done at the time.
Going to try and take it to one of the transmission shops and see if their scanner reads any codes. While we have spent a good bit of $$ in the last 3 months, it's been much more than a daily driver or grocery getter...it's taken us to some cool places across the US.....

I'd like to keep this 3rd Gen awhile longer, I just want to spend wisely on it.

Thanks.

 

[Dredwolf]

Well, struck out at the transmission shop I chose, it's a family-run place and the office manager is in the hospital, so several of the techs were visiting her.. The one guy there said they were booked for two weeks solid.

Does the FORscan software read the transmission codes on the 3rd Gen's if I get the right adapter?

 

[imp]

@Dredwolf
Not all code readers are transmission code capable. However, AFAIK, a transmission code being "set" always throws a CEL - Check Engine Light "ON". Depending on the cause, the OD OFF light may also flash. 4X4 AUTO is nothing more than a turning on of a magnetic clutch in the Transfer Case which then drives the front wheels. It would not likely have anything to do with a 4-5 shift problem. BUT, one off-sized tire CAN confuse 4X4 AUTO, and on pavement will cause some jarring experiences.

Keep in mind that the 4-5 shift can occur at as low a speed as 40 mph under minimum throttle conditions, and following that 5 or 10 mph faster, the Torque Converter Clutch engages, causing what "feels" like an additional "shift". TCC always happens last, when approaching cruise speed. Diagnose a TCC problem using the tachometer. If added LIGHT throttle movement causes no jump in rpm, the TCC is engaged. At speeds below 40 mph, the tach needle will always "jump" as the TCC is never engaged then. Also, at cruise speed, TCC engaged, any quick release or lessening of gas pedal demand ALWAYS releases TCC, so the driver who constantly gets on and off the throtlle is unknowingly killing the TCC parts sooner. Often the first Solenoid to quit. imp

PS: @JK080 makes a living fixing these transmissions. If he happens to see your symptoms as you describe them, he knows an infinite amount more than me.

 

[JK080]

"Nothing happens under hard acceleration, or steady pulls up a grade, or coasting, but if you are barely on the accelerator, above 40 Mph, it may happen once out of every three times."


This makes me think you are describing a torque converter engagement issue, maybe try some shudder fix, this can help with converter engagement issues. If it won't go away the converter itself may have a problem.

 

[Dredwolf]

@Dredwolf
Not all code readers are transmission code capable. However, AFAIK, a transmission code being "set" always throws a CEL - Check Engine Light "ON". Depending on the cause, the OD OFF light may also flash. 4X4 AUTO is nothing more than a turning on of a magnetic clutch in the Transfer Case which then drives the front wheels. It would not likely have anything to do with a 4-5 shift problem. BUT, one off-sized tire CAN confuse 4X4 AUTO, and on pavement will cause some jarring experiences.

Keep in mind that the 4-5 shift can occur at as low a speed as 40 mph under minimum throttle conditions, and following that 5 or 10 mph faster, the Torque Converter Clutch engages, causing what "feels" like an additional "shift". TCC always happens last, when approaching cruise speed. Diagnose a TCC problem using the tachometer. If added LIGHT throttle movement causes no jump in rpm, the TCC is engaged. At speeds below 40 mph, the tach needle will always "jump" as the TCC is never engaged then. Also, at cruise speed, TCC engaged, any quick release or lessening of gas pedal demand ALWAYS releases TCC, so the driver who constantly gets on and off the throtlle is unknowingly killing the TCC parts sooner. Often the first Solenoid to quit. imp

PS: @JK080 makes a living fixing these transmissions. If he happens to see your symptoms as you describe them, he knows an infinite amount more than me.

Good to have that confirmed on the CEL on these vehicles...I suspected as much.

The "feel" of the behavior we are having very much resembles the jarring you can get from the 4X4 Auto with a single low PSI tire and sudden turns...not a complete "bang", but startling to the driver, because its happening during what should be a simple, straight-line drive along a city street or country road.

 

[Dredwolf]

"Nothing happens under hard acceleration, or steady pulls up a grade, or coasting, but if you are barely on the accelerator, above 40 Mph, it may happen once out of every three times."


This makes me think you are describing a torque converter engagement issue, maybe try some shudder fix, this can help with converter engagement issues. If it won't go away the converter itself may have a problem.

As much as I hate to even think it, I can't help but wonder if the filter and fluid change stirred up something, because (insert Dun Dun DUNNN music here) it started after the filter and fluid change. The magnet in the pan was in the wrong spot from the last shop servicing the transmission before we made the trip to Utah and Colorado, and while it had a metal sludge coating, I have seen much worse in transmission pans.

Thinking it through, and the speeds/throttle positions when it occurs, it seems to be happening right in the "zone" where the torque converter clutch would be engaging or releasing.

 

[Dredwolf]

"Nothing happens under hard acceleration, or steady pulls up a grade, or coasting, but if you are barely on the accelerator, above 40 Mph, it may happen once out of every three times."
This makes me think you are describing a torque converter engagement issue, maybe try some shudder fix, this can help with converter engagement issues. If it won't go away the converter itself may have a problem.

The recent cold snaps we have had here in the southeast generated some more info, as I am trying to rebuild my cash reserves for repairs. During the wife's 12 mile drive to work before 8 AM, no issues. During the drive home, with maybe a 3 mile detour for grocery store, it will usually happen. During the recent cold snaps, where the air temp is staying below 50 degrees during the day, no issues during either trip.
We have not tried any interstate travel at this point.
When I changed the filter and the fluid that drained, I replaced with Mercon V, and filled until it ran out the fill tool, and checked the level with the Explorer level on jack stands twice, with the pan warm. Have I botched something or having some odd weirdness with viscosity? Or does this better target the converter as the issue?

 

[Elliott hopson]

Sorry for being off topic, but what tire size you running? Looks good!

 

[Dredwolf]

Sorry for being off topic, but what tire size you running? Looks good!

265/70R16 Cooper Discoverer AT3's....after trying a set for our trip to Colorado and Utah, with all the different terrain, and LOTS of highway miles, I'll keep buying them as long as I can get them. Planning for a set for my 2003 Jeep WJ daily driver too, good highway, rain, and even snow (least what we get here) manners, and good performance off-road. They even clean well with a stab at the skinny pedal, a really good A/T tire, IMHO.