Hi- I recently purchased a 1997 F150 Supercab Lariat 4x4 w/ 4.6L. I really like the truck, and am happy to have found this website as a resource. I was wondering if someone could give me some insight/direction how to handle a transmission problem. I apologize for the length of this post! Here is the sequence of events:
-OD light began flashing. It would begin flashing shortly after starting and driving. It would reset each time the truck was turned off. At the time, I was unable to determine what set of conditions caused it to begin flashing, as it seemed pretty random.
-Took it to a local shop. They were unable to pull any codes (since the light wasn’t flashing at the time). They test drove and said it seemed ok, but to bring it back if the light came on.
-Took it back when the light came on again. They said it was a “1-2 shift error” code. They said this indicated internal mechanical problems, and the trans would have to be removed for further diagnostics, likely to result in an $1800 rebuild. I was reluctant to proceed since the trans really seemed to function ok.
-Took it to another shop for a second opinion. They also pulled a “1-2 shift error” code, but said the fluid level was a little low (I had checked it already, but those dipsticks are tough to read). They added fluid and said to come back if that didn’t help. I was skeptical, but the light didn’t come on again for 2 or 3 weeks. I was (temporarily) happy the problem seemed to be taken care of.
-2 or 3 weeks later, the light began flashing again. I took it back to the second shop. They again pulled a “1-2 shift error” code. (I think they said code #781?). They test drove, and said the same thing as the first shop. The trans would have to be removed and disassembled for further diagnosis, likely to result in a $1000 - $1800 rebuild. Again, I was reluctant to proceed since the trans seemed to work ok, and since no one could seem to satisfactorily explain to me what might be the cause. (i.e. “we’ll just take it apart and see what we find”).
-Took it to a third shop for yet another opinion. This was a much smaller shop. They test drove, and said the trans seemed to function just fine (which is what I have been thinking all along), and that there might be an electrical malfunction of some kind. As I said, this shop is a very small operation, but they have been in business for quite a while. They did not have a code scanner but have an arrangement with another repair shop (not transmissions) do transmission code diagnostics. The cost would be about $50, but I was told this would be a much more thorough diagnosis than the free variety at the larger transmission shops. I haven’t done this yet, but am leaning in this direction, since this guy seems genuinely interested in diagnosing the problem before tearing things apart.
-I have since researched this transmission (internet research), and learned about the 1-2 accumulator problems, and the intermediate one-way clutch problems. I have also read about a number of instances of broken accumulator springs. I would like to pull the pan to check the accumulator and springs, and apparently I can check to see if its been updated to a mechanical diode by rolling the truck back and forth and listening for the ratcheting sound? Could my problem be related to either of these components?
-Just a couple more side notes. I have noticed that the light usually seems to come on after 1-2 shifts, but occasionally it will begin flashing after a 2-3 shift, and maybe even after a 3-4 shift (not sure about that one). It also seems to occasionally come on after a decelerating downshift (3-2, I think, but maybe 2-1, I’m not sure). Also the light seems to be more prone to come on when the transmission is cold. Once its warm, sometimes I can drive without it coming on at all. Also, the 1-2 shift does feel a little late on occasion, but I’m not really sure how it’s supposed to feel. I can’t detect any slipping to speak of. Also, there were a couple days when the TC would not lock up for a few minutes on the freeway. This symptom seems to be gone now, though.
If you've made it through the post this far... Thanks!!! Any input as to what might be happening or what should be done, would be greatly appreciated!
No offense,but you have a pre-98 unit.
They were worthkess. 98 transmissions are way better and 2001 up even better than that. I don't recommend fixing that transmission. I would get a later model unit.
Alan
BTW I would guess you have roller clutch problems.
rsc , besides not being as good a transmission as the later ones, it seems that the trans may be good.
Just that the solenoids may not doing there thing in an intermittant way.
The pan needs to come down, the valve body and solenoid assembly tested and other items checked, then go from there.
Since you/they didn't give the code scanned, I would assume it was P0781.
Your other shift lamps would have been 782,783 etc.
The solenoids are tested by the PCM with 5 different tests to pin point the malfunction. This in not to say there arn't other transmission problems.
You or some one has to take the min. steps to determine if solenoids and/or there are other problems with the valve body or other internals before a decision can be made as to what you will do.
The $1800 for repair is about near the going rate if the trans has to come apart and have bands and clutches replaced etc.
For less than that level of repair, the cost should be much lower.
dirtydog- no offense taken. I understand now that the ’97 transmission has some shortcomings. However, I am reluctant to simply throw it away. After all, it does seem to function ok, for the time being. If it does die completely, (maybe sooner than later if you are right about it having roller clutch problems) then I will certainly look into upgrading to a newer unit. I am wondering, though, if the ’97 4r70w were to be rebuilt utilizing a mechanical diode clutch and updated 1-2 accumulator, could it not be a reasonably serviceable unit? Or does it have other shortcomings that can not be updated?
bluegrass- you are correct, as I mentioned above the code was 781.
I will go ahead and pull the pan and inspect the 1-2 accumulator and springs. Does the valve body have to come down to inspect the 2-3 accumulator? Is there a procedure for checking out the solenoids while it is all apart? Is there anything else I should be looking at that time?
The clutches in the 97 units were of a early poor design, they should be replaced with better clutches from the 01 up units. 98 clutches improved but 01 are the best.
The 97 also has a roller intermediate clutch that is very prone to failure. You want to install the 98+ reverse drum and intermediate clutch in it. Other things got better too ,but those are the most significant.
Alan
First I just want to say that my first, very abused (hot rodded, shift kit installed, towed heavy) 97 4r70w lasted for better then 140,000 miles before losing 4th. I then drove it for 6 weeks with the OD locked out while I waited for a new transmission to be delivered. This included towing my trailer for more then 200 miles since I was towing when I lost 4th.
I also understand that if the rebuild is done with all updated parts, as most good transmissions shops are suppose to use, it is ok to re-use the 97 transmission case and shafts as there is no difference in the basic transmission from 97 to now.
As I re-read my post it reads different then the intent. I was not challenging what was posted earlier, only trying to clarify. I wanted to let others know that my 97 trans got what I thought to be pretty good service.
The second part was actually a question. I recently had my performance transmission destroyed when I blew a U-joint at 70MPH. I had to get it fixed fast and I went to a shop that has a very good reputation. They had to obtain a core transmission and I inquired as to what year the core would be from. The shop owner told me that it didn’t matter. He said the rebuild kits are purchased from a vender who Up-grades them to current specifications. He said the kits are complete and include any changes made by Ford to improve the transmission. He also told me he replaces all wear items in the transmission and checks any reused parts (gears, shafts ect) for wear.
Does this sound correct or are there deficiencies in the earlier transmissions that just can’t be fixed?
I never did get an answer as to what year my core was from. Is there a way to tell on the transmission?
Pre 96 cases had problems that could not be fixed. The rest just becomes an issues of it is cheaper to buy a later core than to fix a pre 98 transmission.
Alan
I just went thru this same problem with my 99 F150. It too has the 4r70 tranny.
Mine started with the flashing OD light. It would run for awhile then the light started flashing. It was slipping some as it shifted but not too bad. I had the code checked and it was the 2-3 shift error. Took it to AAMCO and at first they said it was a bad sensor. After test drive, they came back with the same diagnosis. Transmission was going out. I talked to some local guys that recommended another shop so I talked to the owner there. I was able to take my truck to his house on Sunday and he drove it in on Monday. They checked and again same diagnosis, that the transmission needed rebuilding. My truck had the towing package on it and I tow my 3500 pound boat a couple of times a year. Well, I found that my truck did not have a transmission cooler on it. How stupid of Ford to put a towing package on the truck especially with a lightweight transmission like the 4R70, and not put a cooler on it.
Well, I had it rebuilt for $1330.00 and it runs great now. The guy tweaked the line pressure a little so it shifts much better. He's going to put in a transmission cooler for me later for around $125.
I may also put in a transmission fluid temp gauge too.
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4r70w Problem?
Linear Mode
