Ford 4R70W shifting problem

billr

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OK, that is what I concluded and how I put it back together. It will go back in the truck tomorrow. This job has been a real struggle, partly because of my inexperience, partly because of poor documentation available, and partly because few people repair their own transmissions these days. Local stock of individual parts is scarce, even form Ford, and parts people have trouble even looking up the proper numbers.
 

JackC

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Bill: You continue to amaze me with the projects and continuing the work and learning that you do. I admire that and am pleased to call you a friend. I have no doubt that all will be well.

Thanks again for the patience and help you have given me and others in the past.
 

billr

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It is up-and-running, seems OK so far but only a few miles on it. It will get 200 miles on it tomorrow and Tues, so I will soon know.

I intend to post more info/ranting on what I went through, but the "backup"for this truck also just died and so did my laptop computer! I may just lose interest in this truck trans and move on...
 

billr

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It has been running for a week now, so I'm calling it done.

I have calmed down now, don't feel the need to vent about this job anymore. I will note that I found more 3/8"-16 tapped holes on this "metric" trans; and several other "gotchas". Any DIYer coming across this thread for info on the 4R70W, I suggest you contact me for details.
 

miketx

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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?
It's a 4 speed and it lives off the TPS and VSS. Disconnect the battery to fully clear the ECM.
 

billr

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Did you note that I am well past the questions in that post? I am nearly an "expert" on the innards of that trans now, and it has been back on the road for a week or more.

I gotta say... it seems like an overly complicated design for 4-speeds. Four clutches and two bands, a lot of friction in there. And the air-check shown by Sonnax shows only testing four ports for the clutches. Does the FSM or ATSG manual show air-checks for all seven (4 clutches, 2 bands, and TCC)? One of my small "gotchas" is that I think Sonnax shows one test port wrong! That cost me some time. Oh, oh... I have started on the ranting that I thought I had moved past by Aug. 30
 

nickb2

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I will however like to hijack this, sonnax is supposed to be a leader, if you really found something wrong, your smart enough to let them check it out. Can you post back if the sonnax company held by its name or just shut you down?
 

nickb2

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sometimes, life reside in the options. Fact, broke my cell phone in my gf futton, I heard a crack, anyway, had to buy a new cell phone, when trying to navigate the net, screen wouldnt go sideways, lo and behold, I did a google is my friend search, stock setting is not set for auto rotate, what does this comment relate to your experience? Did sonnax sell you the right thing? or did you express yourself wrong?

From my understudying, sonnax is a real good company and they live by word. ;)
 

billr

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I did not get any parts from Sonnax; but was using page 2 of this as a guide for the air-checks:


My perception is the arrow for the "forward clutch" passage is pointing to the wrong area. However, without having a trans opened-up to play with, I can not double-check this; so I won't challenge Sonnax at this time.
 
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