Ford Transmission...

I have a 99 E250 work van with the 4R70W transmission. It started slipping in first. Almost acted like it was dropping out of gear for a split second. It would only do this when it was hot. Would run normal all morning and as the day got hotter it would start acting up. By the end of the day it would drop out of gear at stop lights. Fluid checked good, no leaks, and the problem only affects first gear at low engine speeds.

Took it to a transmission shop and had the transmission rebuilt. Two days later the same problem showed up. Not as bad, but still there. Back to the trans shop, they made some adjustments. No problems for a couple of more days. Started doing the same thing. Once again not as bad. Back to the shop, the guy decided the case was warped. He replaced the trans with another rebuild. It has been running great for a week and a half. Towed a car forty miles, and 3000#s of doors 100 miles with no problems. Yesterday afternoon, it did it again while accelerating hard (WOT) from a light. Just a couple of shutters, I'm stumped, the transmission guy is stumped. You guys are the smart ones, so I am hoping you have some ideas.

Thanks.

Numbah 1 thing to check: grounds (and electrical connectors in general). Crappy grounds/connections = TCM is vastly confused and in most metals resistance goes up with temperature.

Dunno about this particular box, but in the '90's GM had trannies which would barf the OD unit if the running lamp fuse was blown. Tow a boat, back into the water, bulb wet, bulb pops, fuse blows, the TCM grounded part of the control unit circuitry through that same fuse, driver didn't know, OD fried by the time he got home.

i probobly have a different tranny in my much older ford van but had the same problem at WOT in first gear after modifying the engine and towing way too much weight. our solution was not to floor it in 1st with a camper behind anymore. lol not very amazing but it worked.

I dunno, I think they all have that problem. The trans in my P71 is the same thing and it shudders like a banshee at certain speeds. If it pukes I'll swap in a Tremec and be done with it. I really don't like the 4R70W...

What gets me is I have three of these vans and this is the only one that does it. It didn't have this problem last summer, and I don't drive it any harder now than I did then. With a all new rebuild I would figure the problem would be gone.

Maybe it's electronics? Mine goes away if I play with the settings on the Superchips tuner, I just haven't had the chance to play with it much lately.

That's another thing, when I got it back last time, the speed-o was off 9mph. I figured they just put the wrong ratio sensor in.

4R70W is a great trans if you build it right. http://www.tccoa.com/articles/tranny/transmission/index.shtml To qoute Norm A "be sure to read and understand the manual before proceading"

I did the J-mod and the Sun-ex sure cure kit to my 96 f150 tow rig with 150,000 on it and now have 158,00 on it and love it. Need more gear in the rear but it goes good. I also did an additional cooler + 4 core rad + Royal purple MAX atf. so it goes trans out to small round aftermarket filter, to 4 core rad to factory air cooler to B&M 11x11x1.5 cooler to back to trans. Hauling 4 ton of wood pellets last year in a 18ft box trailer my trans pan got to 175deg Truck was floored most of the way....poor old 302 and 3.58 gears. but it saved me $250 for delivery....

44

Another long shot: wrong fluid? I don't remember about that particular box, but Hondas and Mopars will shudder and shift hard if the wrong fluid is used. I also recall something about oxidized fluid causing shudders etc. I'm not normally a snake oil advocate but IIRC there is an additive for the Honda/Chrysler trannies (it's a friction modifier, smells a bit like olde tyme 90wt) which is supposed to help those a good bit.

Yes you must use the proper juice there is a converter but it's not a true working fix.

Check out the trouble shooting tccoa page #15 sounds like you have a blown seal as its worst when hot. or a still dirty regulator from the orginal failure.

somewhat unrelated, but I was told by my ford mechanic friend never to complain about the performance of a 4r70w that wasn't being run on the correct ford brand atf.

My grandfather has a ford e150 conversion van and had similar problems. short story is that he changed the plugs, replacing the oem with some autolite plugs from oreilly or similar place. a few weeks later, any time he gave it any throttle it would start jerking like the trans was popping in and out of gear. took it to the dealer and they put a new tq converter in it, and it still did the same thing. took it back and they did some more digging, they replaced the autolies with oem motorcraft plugs and all was well again.

Ya know, Isuzu V6's with the ion sensing modules would do something similar to what Strizzo describes. That system fired a spark during the exhaust stroke and used the voltage to determine how complete the burn was. If you used anything other than the OE supplied plugs, when you came to a stop there would be a 'clunk' and the 'Check Trans' light would come on.

44Dwarf wrote: 4R70W is a great trans if you build it right. http://www.tccoa.com/articles/tranny/transmission/index.shtml To qoute Norm A "be sure to read and understand the manual before proceading" I did the J-mod and the Sun-ex sure cure kit to my 96 f150 tow rig with 150,000 on it and now have 158,00 on it and love it. Need more gear in the rear but it goes good. I also did an additional cooler + 4 core rad + Royal purple MAX atf. so it goes trans out to small round aftermarket filter, to 4 core rad to factory air cooler to B&M 11x11x1.5 cooler to back to trans. Hauling 4 ton of wood pellets last year in a 18ft box trailer my trans pan got to 175deg Truck was floored most of the way....poor old 302 and 3.58 gears. but it saved me $250 for delivery.... 44

we had to floor it much of the time towing a 5000lb camper before the whole chip and k&n and header and gibson exhaust thing. then it was totally ok. it cracked up the clear coat on the hood from the heat of the engine but it still runs great. these 302's are real tough

Update for you. After multiple trips to the tranny shop chasing the same problem fist gear finely puked for good. Ran it up to the local Ford dealer figuring with it definitely broken maybe they could find the problem. Two hours later I get a call from the SA. The wiring harness from the ECU to the transmission had shorted out. $350.00 and she is supposed to be good as new.

figured it was wiring/electronic

i hate my 4r70w and it's been getting worse by the week

Sorry I didn't catch this post earlier. But for future reference. If something like this happens in only 1 gear, and it's not happening in any other gear, then it's likely not a mechanical problem. Every mode of every one of the 5 gears in the 4R70W (AODE, AOD) shares an active clutchpack with at least one other gear. So problems that are specific to one and only one gear tend to be electrical, since it's being caused by a set of conditions, and not by a faulty clutchpack engagement.