01 Excursion, 7.3 engine, 2wd, 60k miles. I believe I may have the 4r100 trans. My transmission started failing today and will not shift from 2-3. When it is trying to do so, and at high rpm, it feels like it is downshifting back to 1st. The suv slows down quite a bit and then suddenly a jolt forward.

I've read a couple of other posts (thank you very much!) and it appears the problem may be a mechanical diode style clutch that needs to get replaced with a sprag style type. I've got 2 left hands and can only manage to change the oil and fuel filter on this suv. How much will this set me back if i take it to a dealer vs a tranny shop?

Thanks a mil!
H

 

Is there a warning light on? Those trans. are fully electronic shift. If there is a concern such as too much slipage, low pressure,ect the PCM will lock the trans in 2nd gear and leave you there. If it will not reset after shutting of the vehicle waiting 10 seconds and restarting the problem is hard fault and needs attention before it finnish's off the trans.
Cant guarantee but problem may not be bad at this moment as may be as simple as inop sensor. Need to have someone run a scantool for codes on this. Prices here for reman is around $2000.00 aftermarket plus labor to R&R. If have a good quality repair shop with access to up to date TSB's for possible update parts to install on repair is usually cheaper and have good warrantee.

 

Slipped me on my last post but be sure trans is hot and in park then check fluid level, sounds dumb but if someone has added fluid the past few days and overfilled it will cause weird things to happen as those clutch drums running in overfull fluid will foam.
Cannot be overfull. Hope this helps.

 

Orin,

Thank you for your help! No warning lights are on and have not added trans fluid. I checked and the level fluid is fine.

I hope and pray it is a sensor, don't have the 2k to get a reman tranny. Two separate friends have referred me a quality shop in town and I will head there on Monday to have the computer checked.

Can I drive to the shop using low 2 gear? It does not seem to have the problem when I'm in that gear.

Thanks again,
H

 

By in town I assume within a couple of miles which would be OK, just be kind of gentle on it and allow some time to get there, but if skips into neutral a feeling of no gears stop and call for a tow truck. The second gear feature wired into the PCM was there as a backup to lower the chance's of further damage to trans or leaving you stranded if possible. Hope you lots of luck on something nice and simple.

 

I'm sorry to say that it's almost certainly the mechanical diode. It takes a major rebuild to replace it because a lot of other hard parts have to be changed to change it. It's going to run at least $2000 on the low side. Sorry.

 

Mark, if I could ask for my own information, this mechanical diode you write of, is it a one way sprag clutch of type but designed a bit different, new and improved? also doe's it coexist with the overdrive drum and require replacement of the center support, drums, and possible shaft. Last trans I was in was the E4OD years back.

 

It's a one way clutch, but not a sprag. The sprag one way is a different design. A trans has either a sprag or a mechanical diode, they do the same thing in the same place.

It's been a while since I've been inside one of these. I remember that the intermediate drum has to change, and there are several other parts that change, too. Each of these parts had to change to accept the mechanical diode, and they need to be changed to parts that will accept a sprag one way clutch.

 

Thanks Mark, as far as Iam concerned this is what the whole thing is about, learning something new every day.

 

Good evening gents,

Well, after limping my 01 Excur to a tranny shop, I've gotten the results and they are not so good. I must admit that I know as much about transmissions as I know about flying airplanes, which is zero. So I'm hoping you can shed some light for me.
Some background info, I purchased this vehicle 1.5 years ago to take the family camping with plans to eventually purchase a 18-20 foot trailer. I don't know what the previous owner did with this vehicle, but it only came with 50k miles so I thought it was a good buy. We have only put 10k miles on it.

The intial plug into the computer to get problem codes revealed 3 problems:

low (ATF?) pressure when in 3rd gear
something wrong with 3rd gear ratio??? and
bad temp to limit (ATF temp?)

Anyways, they had to took the transmission down and found these additional problems:

1. pump failed -- is this the ATF pump or engine water pump? Mech said it was pushing 65-75 psi in gears 1-2, but only 5 psi in gear 3. He said it has probably been a bad pump for some time. Why no light on the inst panel?
2. worn out sprag -- I thought this tranny had a mechanical diode? Does this mean it was repl previously?
3. torque conv no good, needs repl
4. banner key needs repl -- what is this?
5. restriction in cooling lines -- cooler for engine or does this have a separate tranny cooler? Shop recommends an after market cooler for the tranny, do I need one if I don't haul anything, yet?
6. direct clutch and fan gear also failed -- what are these?
7. OD light on shifter does not work, should this have foretold of problems to come?

Shop owner also mentioned I needed some computer updates, what does this do?

Sorry for all the questions, but as you can tell, I'm trying to learn from this experience so I can notice signs of this happening again in the future.

Thank,
Hugo

 

I'll hope mark jumps in here too, but some of this sounds pretty familiar, I'll jump to 7 first as OD light rather than a light in the dash would have been flashing when you were having trouble had it been operational (I thought the newer model would be warning light in dash) to indicate concerns with trany. Now to go down the list:
1:Trany pump located in the front of the tran behind the touque converter, may need to be replaced for scored, damaged, but without personal inspection, left to speculate, if the pump did not whine or make other noise's it could be OK as the pressure indicated it was able to build pressure for 1st and 2nd but lost on 3rd would also answer question 6 as when 3rd gear was atempted there was so much leakage in that curcuit to prevent direct clutch pack from engadging. I would want to know why the pump was condemned for excessive leaking in 3rd and to exsplain why they felt otherwise the pump should be replaced.
2:At times parts will be called one thing from Ford but aftermarket will call them something else when they are the same thing, I don't know in this case but have had to decode parts in the past, kinda like learning another language.
3:The touque converter lockup clutch could have been burned badly like the 3rd gear which is located inside the touque converter housing and connot be accessed with out proper rebuild equipment, but should have a bluish color to it if that's the case. May also be a lot of contamination and debris in it also that would warrant replacement.
4:I'm at a loss, not a good excuse but I have been out of Ford 9 years and got behind.
5:I would think that they were talking about the trany cooler and line's, when I did a repair or replace on the newer vehicles in the day I simply pulled the radiator and sent it out for a new cooler to be installed in it, got real touchy about cleaning the old cooler in the rad as you didn't always get the debris out and could distroy the new rebuild. Sounds like your trans cooler took a hit of garbage because from what I get out of this your trans sounds like it was about ate up internally. If your planning on pulling a trailer I would go for an aux trans cooler now and forget the one in the rad., save some buck's and have it set up to work hard.
The P.C.M. or computer that your outfit has is a OBD2 Generation 5 and with all that being said, it unlike the earlier computers before now has a base memory that can be reprogramed by update to meet the needs for design changes or alter the memory tables to a new value that would among other things possibly increase oil pressure a little or change settings for shift engadgments, these updates address concerns that are discovered only after the vehicle has been out in the field in use under real life conditions.
I hope this was taken as something to inform and help as I in good faith wrote what I thought was tryed and proven through the years.

 

The pump doesn't know what gear the trans is in. It just makes pressure when the engine is turning. Low pressure in 3rd gear is NOT a pump problem, it's a failed direct clutch problem. When the clutch fails there is a BIG internal pressure leak when in 3rd gear, this is why the pump can't make pressure in 3rd. I forget what pressure should be there, so it is possible that the pmp needs to be replaced.

The first half of the 2001 diesels had the mechanical diode. The second half of the year's production had the sprag clutch.

You must have misunderstood, or they are trying to snow you. There is no such thing as a banner key.

Trans cooler. You need a new one. When a clutch fails parts of the clutch will go into the cooler and plug it. It can't be cleaned, it must be replaced or you will be replacing the trans again.

The direct clutch is the clutch that is applied when the trans is in 3rd gear. There is no fan gear, there are sun gears, planet gears, and ring gears.

Yes, the OD light would have flashed telling you of the codes stored in memory.

Ford periodically releases improved software for the engine and trans. It may make the truck run better and last longer.

 

Hey Mark, Thanks you did nice job of cleaning that up, I have to learn to take my writting down a notch or two.

 

Good morning gentlemen,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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Let me first start by saying thank you for helping me understand the different parts of the trans for my excursion. I'm trying to learn as much as I can so that I can avoid having to go through the pain of forking over 2k again.<o></o>
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When the tranny mechanic told me of my problems 3 days ago, he invited me down to his shop to show me what happened. I could not go until yesterday afternoon, but the transmission was all buttoned up already and waiting installation. He showed me the parts and pieces that he removed, some burned and at least one broken (sprag one way clutch). He also gave me 2 cool looking pieces of steel, one rides inside the other, has one less tooth and apparently goes inside the pump that failed. The edges are pretty rough and he said they should be smooth.<o></o>
<o> </o>
I asked about the mechanical diode since this suv was made during the months Ford had the problems with this tranny. He said this one had a sprag clutch and pulled it out of the trashbin to show me where it broke. About 40% of the teeth on the outer edge broke off and there is a large crack in the piece. This shop was highly recommended, but I’d like to make sure what he gave me was the sprag clutch and that a mechanical diode was not put back in (he indicated all the parts replaced where OEM). Where can I find a diagram of the 4r100 trans? He showed me a diagram of a previous Ford tranny (E4OD?) and where the sprag clutch was located and on that diagram it was labeled as a one way clutch. I also have a picture of the part if there is a way to attach it to a thread.
<o> </o>
Also, he highly recommended the additional cooler and showed me where it would be installed towards the front of the radiator. He didn’t give me a price because he first wants to check if there is still a restriction in the lines with the repaired tranny. What brand/type is recommended for this vehicle and what should I expect to pay for this? He also recommended a tranny temp gauge since my instrument panel does not have one, what brand/type is recommended?
<o> </o>
My cost so far is up to 2k and that includes diagnosing the codes, removing the tranny, replacing the clutch, pump, torque convertor and some (though I don’t know how many) of the gears. Does that sound reasonable? He still wants to diagnose why the OD light is not turning on (to notify when something goes wrong with the tranny).
<o> </o>
By the way, the banner key he mentioned is something that looks like a pattern template, is black and has a bunch of holes in it. He said that is where the ATF fluid travels through when shifting between gears.
<o> </o>
Thanks again for all of your help.
Hugo

 

From what I understand if your trany had a mechanical diode to start with, there would have been substantial parts replacement to install the updated sprag clutch and so with that thought I would think that it should have been impossible to install a mechanical diode back in one as most parts associated with the defective diode should be no longer available possibley including the diode.

The cooler lines wouldn't be clogged I wouldn't think but only need flushed and blown out to remove debris, the OEM trans cooler as stated before removed and replaced or bypassed only, Ford rebuilders AER sent an inline filter to cooler and indicated that was allright if the cooler was flushed too, but I don't know now if that is still acceptable. Your original plan to have a external cooler mounted at this point would be my choice, I have not installed a cooler for a while but would think something in a Heavy Duty RV or what space will allow.

The OD light should not be much, should only be the light and switch combo that goes into the end of the PRNDL lever or wirring comming up the column and into the lever, have seen either bad before. The light along with flashing to indicate concerns also lights and stays on steady when you cancel overdrive through the button on the end.

The banner key still has me stumped, do not have a breakdown for that trans but will as time allow research, even maybe a lingo nightmare as I had stated earlier in previous post that OEM will call it one thing and aftermarker will call it something else, I have had this form of a nightmare more than once when even after having brought the part in still got a blank stare and I dunno, Iam for being a mechanic for a lot of years still retain my sanity as I have still not went with my origanal idea of jumpping the counter and choking the living daylights out of by then someone that truly deserves it. Even though true, I hope some humor was derived from that last statement.

At this end the gadge is a good idea but I don' know if it is feasable as there has to be a place to mount without tearing up the interior, a rule of thumb that through the years seems to still apply that when pulling loads is to cancel overdrive,for emmsions and fuel economy the OD resets each time you shut off the vehicle and overdrive button has to be depressed for continued operation. Other makers use a special "TOW" button and Ford probably does now to a form thereof that sets the shifts higher and increases oil pressure to reduce burn ups with heavy loads there are other things too that are used with electronic shift trans but the post would get even more wordy than I normal do. A quick note to finnish is if you have the owners manual to the vehicle or can get one it will give a guide as to how the trans should operate under different conditions and what you should do to set it up for a given task.