Yes, Another Tranny Question Post...

[Dalmus]

So I have an '03 XLS (4.0, not the 4.6) with 184,000 miles on it... Over the past 3,000 miles, I've started to get a rather rough shift into and out of 4th after the engine has warmed up. 4th to "OD" and back is fine, and Reverse - 3 are fine. There is no RPM flare, just the feeling and sound of it seeming to stick during the shift.

I've also started noticing a rumble and vibration once I hit 50-55 mph. It goes away mostly when I take my foot off the accelerator, and if I keep the accelerator at a point that's neutral (just below "maintaining speed" pressure), it gets much louder and feels stronger. Similar to the feel of driving over a worn down rumble strip. I can't reproduce this sound or vibration be reving the engine to the same RPM's at a stand still, so I don't think its exhaust system related.

I've managed to check the fluid, and it looks relatively good (still red and reasonably clear... amazing for fluid that has 120,000 miles on it). I've had a couple mechanic friends tell me that its not likely to be the filter if all the other gears shift fine.

Question for the group... Is it possible its anything else that is fixable besides a complete rebuild? If it needs a rebuild, I'm going to either sell it to some handy guy that can do most of the work himself, or donate it and take the tax break.

I'd love to be able to keep it as a second vehicle if possible, but just can't justify an $1,800 repair when I have a new Escape with towing capacity right next to it in the driveway.

Any ideas?

Thanks!

 

[Dalmus]

Okay, so I had another thought.... Two, actually...

Thought 1: Since I don't have any RPM flair, and I have no flashing O/D light, could it be its "just" a sticking solenoid? If so, looking at the walkthroughs and videos, it doesn't appear to be a very tough job to do myself as long as I have a way to raise the truck off the ground enough to work under it. Would a bad solenoid pack cause the odd shift into and out of 4th only?

Second thought: The fluid IS still red, but definitely darker than "new" fluid, and doesn't really smell burnt to me... Should I just go ahead and drain out what's in the pan, drop it, change the filter, and pump new stuff back in? I don't want to risk a flush at 184K miles, but maybe a 50% change is safe.

Or should I just break down and take it to a dealer and get their opinion?

 

[rrgone]

I'm not much of a tranny guy so I will remain silent rather than exhibit my ignorance on the subject.

I have seen that description of driving on rumble strips a time or two. Usually turns out to be a automatic 4WD issue. Disable your 4WD system temporarily and see if it stops. Easiest to pull the transfer case power fuses under the hood to disable Auto 4WD system. Let us know if that turns out to be one of your problems.

 

[imp]

You need to determine whether this is an issue with the Torque Converter Clutch (TCC) rather than O/D (5th.) gear issue. The last thing to happen during MINIMUM throttle acceleration getting up to around 50 mph is the TCC engaging. You should be able to count "drops" on the tachometer, first one is shift to 2nd. gear, second is 3rd. gear, etc., until the fifth drop which is the TCC. After all that has happened, SLIGHT increase in throttle should show NO INCREASE in rpm, if TCC has engaged. Try that after the fourth drop, the shift to 5th gear, Overdrive gear, and you should see immediate increase in rpms, indicating the torque converter is still part of the power flow, clutch which locks it out not yet engaged.

The tach can save lots of guesswork, if you use it knowledgeably. imp

 

[Dalmus]

RRgone,

Since I had a longish trip to make on Sunday, I tried removing the 4x4 fuses (two 20 amp fuses)... It made absolutely no difference other than making the two 4x4 lights flash on the dash occasionally. I still had the "rumble strip" effect when I had slight pressure on the accelerator, decreases to a faint rumble when I have no pressure or heavy pressure on the accelerator.

Imp,

I will try your test this afternoon and report back. Thanks!

 

[rrgone]

RRgone,

Since I had a longish trip to make on Sunday, I tried removing the 4x4 fuses (two 20 amp fuses)... It made absolutely no difference other than making the two 4x4 lights flash on the dash occasionally. I still had the "rumble strip" effect when I had slight pressure on the accelerator, decreases to a faint rumble when I have no pressure or heavy pressure on the accelerator.

Imp,

I will try your test this afternoon and report back. Thanks!

Thanks for the feedback. Good luck!

 

[Dalmus]

Imp,

I tried your suggestion this afternoon. After it dropped into "5th," I was able to increase the RPM's by 200 or so by putting slight pressure on the accelerator. One other thing I noticed, if I give it a lot of power accelerating from a stop, the rough shift into 4th was MUCH diminished.

I also noticed that if I gave it more power than normal, but not quite enough to drop into a lower gear, the whole truck seemed to alternately hesitate and lurch as if something weren't quite grabbing properly. Not particularly violent, but enough to be noticeable.

Hope this narrows it down for those who are in the know.

Thanks

 

[imp]

Imp,

I tried your suggestion this afternoon. After it dropped into "5th," I was able to increase the RPM's by 200 or so by putting slight pressure on the accelerator. One other thing I noticed, if I give it a lot of power accelerating from a stop, the rough shift into 4th was MUCH diminished.

I also noticed that if I gave it more power than normal, but not quite enough to drop into a lower gear, the whole truck seemed to alternately hesitate and lurch as if something weren't quite grabbing properly. Not particularly violent, but enough to be noticeable.

Hope this narrows it down for those who are in the know.

Thanks

Need to know if you mean the "5th" drop of the tach, or 5th. gear. "5th" drop of the tach is the engage of the TCC. "4th" drop of the tach is the shift into 5th GEAR. There are 5 gear speeds and an additional change which "looks" like a shift, but is the TCC engaging, which drops rpm similarly to a gear shift.

If after the "5th" tach drop in rpms, a slight additional demand of throttle immediately causes the tach to jump up a bit, the TCC has FAILED to engage, or is slipping, that being less likely than fail to engage. The thing surprising me is that no flashing "O/D OFF" light is occurring. The computer should detect a failed to engage TCC as it checks shaft speeds, and respond by generating a trouble code, and flashing light. You MUST check for codes using a "CAN" protocol equipped code scanner. Others won't read transmission codes. imp

 

[Dalmus]

Hi Imp,

I actually made a video yesterday, and reviewing it now, it looks like I missed the subtle drop in RPM's that would be after 5th gear. So when I'm saying "slight gas," it is after the 5th drop in RPM's. You can hear the sound of the shift into 4th gear also if you listen.

http://tinyurl.com/l5w5na4

I know the O/D Off light works, as I can push the button and it comes on just fine, as well as during engine start. I will see if I can get a code read tomorrow.

Thanks!

 

[Dalmus]

I asked our bus mechanic (I work for a school bus company) to check to see if there were any transmission codes to be read, and he didn't find any. He's not a tranny guy though, and couldn't really offer any suggestions beyond avoiding changing the fluid on a high mileage tranny.