Ford 4R70W shifting problem

[billr]

Make

Ford

Model

F-150 2WD

Year

1999

Miles

unk

Engine

4.2L V-6

Yes, this is the same truck I put a JY trans into last Nov. It is about 200 miles away right now, I only have "phoned-in" symptoms but want to get started gathering info. Hopefully it will get back after a long slow drive tonight.

For the last few months the 1-2 shift has been delayed, the engine often has to rev up toward 4000 rpm or more before the shift happens. Trans fluid and filter were changed about one month ago, no change. No codes set as I recall.

Today it will no longer shift out of 1st when the shift lever is in "D". However, it will do the 1-2 shift if the lever is in "2". Once in 2nd, moving the lever to D has not effect, the trans stays in 2nd. Fussing with the OD button seems to have no effect. Yes, fluid level was checked today and is OK.

I am well-familiar with the solenoids in this trans (the "easy three", at least) and the connector to them; so I will do some resistance checks if/when it gets back. Also, with live-data I will look for other clues.

Any other hints?

 

[bp042665]

could have a stuck valve or a cracked drum have seen both in this transmission

 

[NickD]

That what use to be the neutral safety switch now had all kinds of extra contacts to control the valves in the AT. And it sure ain't gold plated contacts. Also have switches on your brake pedal and software loaded into electrically erasable memory that can also be erased by a glitch. and finally an AT connector located at the bottom that is exposed to road salt.

Should advertise, if you want problems we got problems. Getting rid of all the analog mechanical controls completely self-contained drastically decreased the manufacturing cost of these things, so to compensate for this skyrocketed the price. An 89 cent microcontroller chip is a heck of a lot cheaper than a control valve and governor.

We also use to use all 16AWG wire, even of a little light bulb because it was more robust, now you can find 32 AWG wire, don't stare at it, will break. Latest vehicles are using a ton of point contact relays for control that are made in China. One little arc on the contacts, won't make contact.

 

[billr]

I'm just getting started, only checked for codes and KOEO data. The only code is P1270, "rev limiter hit". I guess that is to be expected, since the return trip was about 200 miles on highway, in 2nd gear.

Live-data shows the range switch is probably OK. However, the TP looks poor to me; 20% to 90% from closed to WOT. Also, baro is low; only 90 kPa at my 250' elevation. Soon I will go for a ride and look for "gear commanded". I am hoping that TP being off is forcing a "downshift" into lower gears!

 

[billr]

Well, the shifting is not responding to the "gear commanded". Live-data indicates that the "gear" progresses from 1 to 3 as speed increases, but shifting does not occur. Why that doesn't set a code, I have no clue.

Solenoid resistance reads OK. The trans fuse is OK, and we are checking now to confirm 12V is getting to the trans harness connector pin.

BP, please keep checking in here, I'm wandering in the weeds and am sure to have more questions!

 

[billr]

Not only am I "in the weeds" but these weeds are alongside a "dog park". Every step I take seems to get me into more crap!

We can't find 12V on the wire that supplies power to the solenoids (pin 4) with KOEO, so I need an electrical schematic. However, if that connector is disconnected the shifting is harsh, like the EPC (LP) solenoid is powered and controlling pressure. If it has power, so must the others, but I want to resolve why we can't find 12V on that wire.... Also, I need a chart for V to temp for this Ford TFT sensor. The resistance we are reading seems way out of range.

The shifting seems to be the same, other than harshness, with the solenoid cable connected or not. It is like this:

D => 1st gear only, pulls OK until engine rpm gets to about 3500, then rpm flares up but vehicle speed doesn't increase. At a stop, the TC seems to stall at 1500 rpm

2 => 2nd gear only, and stays locked to engine. TC stall is about 1800 rpm

1 => same as above!

Although the TPS is suspicious, as mentioned before, I don't think that could cause so much trans grief. Besides, live-data shows the shifting is not going to "gear commanded". Why are there no codes being set??? Yes, with the solenoid connector off all the appropriate codes are set; and with it on live-data show "no faults" for all the circuits. I am dependent on Ford and Snappy to be giving true info, of course.

BP, since the trans will hold for a stall, can I hope there is not a cracked drum/shell in there? And why could stall speed be different in D from 1 & 2? would think, if the trans innards are stopped from rotating, stall would be determined only by the TC characteristics. Or, does that difference in stall speed almost guarantee that something is slipping inside the trans?

PS: is this really a 4-speed trans, or is the 4th speed (OD) merely a slight increase due to TC lock?

 

[bp042665]

ok bill i am thinking the direct drum is cracked at weld it applies for third and stay's applied for fourth with the overdrive band from what im reading and yes this is a true 4 speed with lock up

 

[billr]

This is the Sonnax info I am relying on for solenoid operation/resistance/pin-out.

http://d2q1ebiag300ih.cloudfront.net/uploads/instruction/file/2170/AODE-4R75E-ZIP.pdf?v=1481748875

I assume that when a solenoid is "on" it is powered, with current through the coil; is that correct? When "on", does a solenoid block fluid flow or open up to allow fluid flow? I am talking about the SS1 and SS2 (also called SSA and SSB), for now.

If I pull the pan (and VB?) is there any way I can inspect for damage to drums? Air checks? That direct one is way to the rear, correct?

 

[bp042665]

ok when on it blocks off the fluid which then stokes the valve when off it opens and the valve strokes back and yes there is a open hole in the case channel you can apply the direct drum its in the rear of case ill take a picture and add it to this

 

[bp042665]

ok there are 2 small holes air test them both i cant remember the right hole but if you dont hear a thug noise out of either 1 then you found the problem if they both hiss you found the problem when the direct drum apply you'll hear a loud thug and maybe a little hiss

 

[billr]

I am kind of headed towards dropping the pan, and maybe VB, for a look-see and the air checks. Dropping the pan is not at all difficult, but it is a messy/tedious process that I don't want to do many times just to trouble-shoot. I see there are a few pressure ports on the exterior of the trans case. Would a gauge on any of those tell us more? I realize I would have to take readings while the truck was in motion and trying to shift; a long hose for the gauge.

There are two other symptoms, flaky TPS and BARO readings, but they are intermittent. I will work to resolve those, but am thinking they could not account for this distinct shifting problem. Also, I need to verify that there is 12V power on pin 4 of the solenoid connector; and the incorrect resistance reading for the TFT sensor. My son has been doing the probing (his truck), but I need to verify for myself.

I took it for another drive, to try "refining" the shift symptoms. I now feel "2" (M2?) holds it in 2nd and "1" (M1?) holds it in 1st. Before, I thought they both held it in 2nd. What confuses me is that the Sonnax link above indicates M1 and M2 set different solenoid conditions than 1 or 2 when D.

Does the ATSG manual show mechanical "power flow" for the various gears?

 

[billr]

I confirmed that there is 12V power to the solenoids and that the TFT sensor resistance is "reasonable". The TPS intermittent was a broken wire, now fixed. However, the TP range is still 20-90% (but reliable); is that range normal for this engine? Regardless, the trans problem is still there. I expected it would be.

So, the pan and VB are off. It is "drip drying" now, so I can get under there tomorrow for inspection and air-check with as little "rain" on me as possible. I'm not very optimistic, especially when I start blowing compressed air into places...

 

[JackC]

Bill: I have been following your saga. I wish I could help . When I was trained on automatic trans in the mid 50's there were no electrical connections at all. I can only wish you all the luck possible. You always amaze me with the projects you take on. More amazing is your patience and persistence.

 

[bp042665]

ATSG yes i swear by there book they are the 1 i take my classes from every year they do a good job the TPS will cause shifting issues but not no gear shift if computer commands the gear

 

[NickD]

Repaired several of these, technology is already over 30 years old, no use in saying time goes by fast. Especially when one is told by a shop you need a new transmission, that will be $4.000.00!

These electronically controlled transmission are far easier than the hydromatics that came out in quantity in 1949, just clutches activated by solenoid valves electronically controlled by an 89 cent microcontroller with software stored in electrically erasable ram. Well that started in 1996, before, in PROM where the code was burnt in.

Is one mechanical activated part, dropping a pawl in a gear when in park, and all these new vehicles demand leaving in park before you can shut down the engine. If someone bumps you while parked, that pawls in an aluminum case can break it costing you an arm an and a leg. You can bypass it but get in trouble with your insurance company, I just firmly apply the parking brake, that is what its in for.

Now how can a scanner tell you when your gear shift is in a certain position, not getting switch contact due to dirty contact. Scanner has not idea what gear you are in, so much easier to remove that gear shifted switch and check the continuity. I just drill out the rivets, and take the switch apart, putting it together with an 8-32 screw with loctite, you can see the burn contacts as well as that cable from the ECU to the transmission. Females can be spread, small jewelers screwdriver can pry them closer against for a tight fit.

The real killer is having to lay out over a thousand bucks for an new ECU that only cost 20 bucks to manufacturer, but since 1996 the code is in electrically erasable read only memory so can be reflashed.

Same with the brake switches, one guy here has no backup lights, those solenoids draw a contact damaging inductive kickback current, really takes a tow on those switch contacts.

Just my worth. Forget the scanner, forget the 4000 bucks, do a visual check on those switch contacts and cable harnesses. We use to use all plated wire, now mostly bard copper and the lightest gauge possible to keep the stock holders happy, screw the customer. when that copper oxides becomes a darn good insulator.

Engineers can only recommend, bean counters have the final say in case you are wondering why you are having problems. Contacts use to be made in the USA and electroplated, EPA banned electrode playing so previous politicians could favor buying chit from China while they lined their pocket books and screwed the hell out of us.