4R70W OD light flash...1-2 shift error

[mnealuf]

I have 97 4R70W and the OD light started to flash over the weekend. I have recently purchased the truck and the previous owner said a local shop re-did the tranny ~10k miles ago. (currently truck as 122k) I took it to local Ford dealer and they said it was 1-2 shift code. (they didn't tell me the exact code.:-(. The recommend a 1-2 shift accumulator. Any thoughts from the experts? I replaced the TCC right after I bought the truck to solve a TC shudder with the help of those in the know here...asking for assistance once again. Is the 1-2 accumulator common and is it something I can do on my back in my driveway. (I have reasonable mechanical aptitude) I am off to read Glaicer's rebuild diary.

 

[boominXplorer]

I have 97 4R70W and the OD light started to flash over the weekend. I have recently purchased the truck and the previous owner said a local shop re-did the tranny ~10k miles ago. (currently truck as 122k) I took it to local Ford dealer and they said it was 1-2 shift code. (they didn't tell me the exact code.:-(. The recommend a 1-2 shift accumulator. Any thoughts from the experts? I replaced the TCC right after I bought the truck to solve a TC shudder with the help of those in the know here...asking for assistance once again. Is the 1-2 accumulator common and is it something I can do on my back in my driveway. (I have reasonable mechanical aptitude) I am off to read Glaicer's rebuild diary.

To get to them you need to pull the valve body out. Its not bad, just check out glaicers rebuild. I broke the 2-3 in my 00 4r70 and the part was 5$ from ford.

 

[mnealuf]

I just read the bible (Glacier's diary) and as always a it huige help. The VB comes off as a complete unit right? I also have a Explorer with the dreaded 2-3 flare so I am aware of numerous VB things and separator plates with the 5R55E transmission, is the 4R70W Vb straightforward? Looks like the 1-23 accumulator is cheap..like 15 bucks.

 

[badge49]

I recently had a similar problem. I was passing another car on the freeway and really opened up the throttle. My truck kicked down a gear like it's supposed to, but the overdrive light started flashing and it wouldn't go back into 5th gear. The overdrive button also had no affect on the overdrive. I pulled over, turned off the truck, pulled my posssitive turminal, cleared the power to the entire truck, and put everyting back together. Works fine now. If you have the same problem maybe this could be an easy fix and save you some trouble?

 

[Glacier991]

I cannot speak for HOW common it is, but it can be a problem. As you saw, removal is pretty straightforward. Drop the VB and there it is. While the VB is out you might want to do a J mod on it.

I apologize for leaving the 4R70W Diary alone for a bit... life and heat got in the way. The VB portion is still shead, but the J mod is pretty straightforward.... you can access the directions on the TCCOA forum in their tech articles.

 

[mnealuf]

I found a bunch of good stuff on the TCCOA board. It looks like the newer rubber style helps salvage cases if the bore is beat up. I will see if local Ford Dealer has updated part and do some research on the J mod. I read somewhere I could get away with no removing VB, now it sounds like it has to get removed.....I am sorta scared about that since I have never do that...but I do believe it comes off intact so should be too bad.

 

[Glacier991]

The older style had issues... was not sure what year the newer bonded one came into existence... gla you found that. The accumulator section of the Diary will get some major work when I get back to it.

And you can do this. Relax and buy a 1/4 torque wrench. No guessing.

ps. Scotchbrite the bore. Worst case there is a boring procedure to renew the bore too.

 

[mnealuf]

I am off to buy the parts from the dealer today on my way to work. I will buy the springs and the piston..any reason to replace the cover (cap)? I have a decent 1/4 drive torque wrench from back a couple years ago when I rebuilt a marine outdrive (bearing preload). I saw the newer rubber style was less effected by the bore being hammered...glad to hear there is a saving grace if it is really ugly in there.....I really don't want to pull the trans out. They say 4x4 are PITA with the torsion bars. I have a ATSG book for the transmission and it also say the S1 can give the code. The trany tech at the Ford dealer that pulled the code said he was sure it was a mechanical problem and not a solenoid. Think that is accurate? He also said it could be the clutch packs, but doubts that because fluid is clean and not burnt. (It is freshly changed from My TCC adventure ~500 miles ago.) My hope is when transmission shop rebuilt the transmission ~10k ago they didn't replace the piston and the clutches are new at that time. It is more difficult with used things where you know 1/2 the history.

 

[mnealuf]

I took 1-2 accumulator apart tonight, everything looked pretty OK...no broken springs etc. Bore had a slight bit of roughness but very little. The accumulator was old style (aluminum w/ o-rings) . I have the updated piston assembly and springs ordered from Ford Dealership and they will be here tomorrow. I was able to remove it without removing VB, I am hoping I can re-install it with leaving VB in place...is that possible? Other than polish the bore slightly with scotchbrite is there any tricks? The inner (upwards) bore was not as easy but I did get a little polishing done, other than no scoring/roughness it that all I need?

 

[Glacier991]

With that you should be good to go. I forgot the 1-2 was in the corner, I was thinking of the 2-3, so you should be able to re-install it without removing the VB. Let us know how it all goes.

 

[mnealuf]

Update: I replaced the 1-2 piston and springs with the updates version. (had older aluminum style). Polished the two bores with some scotch-bright and re-installed...drove couple miles 1-2 shift felt good...2-1 downshift felt good...I am starting to be pleased then bam..OD light back flashing. The the shifting is odd (I assume it goes in a "limp home mode". I didn't replace the cap and/or cap o-ring and I thought maybe that was dumb since I had it all apart. Also I had some difficulty getting the cap past the preload and install snap ring but I eventually got it. I was afraid I harmed the cap o-ring once but removed it (before I had snap ring in) and the o-ring looked OK. I dunno what else to try.......thoughts from the experts?

 

[Glacier991]

let's have you pull the DTC (diagnostic trouble code). I think your problem will be well defined there, and yes you probably are going into limp mode....So, next step, pull the codes and report back what you get.

 

[mnealuf]

I will pull codes tomorrow and post what they are. Hopefully my buddies has access to hand held scanner will gather them (his neighbor is automotive tech so it a pretty high end). I pulled them tonight before truck was back together and it had C1234 &C1148. (I think they are both RF ABS sensor). Perhaps local dealer flashed the tranny codes when he pulled them Monday. The codes stay until reset correct? If not then perhaps I will return to dealer. I saw on the web there is updated accumulator cover that is rubber vulcanized similar to the piston. I was thinking I might do that and a solenoid pack while I a in there...again. I hate automatics. Glacier you don't have any 4R70Ws 4x4 ready to sell do you?

 

[Glacier991]

Glacier you don't have any 4R70Ws 4x4 ready to sell do you?

The One in the Rebuild Diary is sold. I have one more 4R70W sitting in my garage to rebuild, but will wait til the one in the Diary is finished, and then need to decide if the next one is 2x2 or 2x4. Unless I can presell it I will probably build it as a HP 2x2, easier to sell than a 2x4.

Meanwhile I have so many waiting projects.... the BW 1354 Rebuild Diary, the BW 4405 Rebuild/upgrade Diary, the Updated Frankentranny Diary (x2) and finally the 4R70W Valve Body Rebuild Diary...oh and the "Painting your Explorer DIY Diary ".....So I have a full plate.... and a full time job and a life - but no wife, which means I CAN do these, eventually without being thrown out of the house.

I'll stay the top photo poster for a while. <grin>

 

[mnealuf]

I pulled the codes tonight. P0781....1-2 shift malfunction. I drove it home from work and 1st couple miles was AOK, then once I felt it slip slightly in the shift into 2nd gear and OD light flashed. I ordered the solenoid pack and updated 1-2 accumulator cover from local dealer....will try that this weekend.....crossing my fingers but not feeling lucky. Glacier, I for one and very happy you are number one poster.......you have taught me a great deal in my time here...many thanks to you and those like you who help and assist those in need.

 

[Glacier991]

Thank you for the kind words. There is good news and potential bad news. The good news is that the 1-2 shift solenoid is strongly implicated in the bulk of these problems throwing this code. The potentially bad news is that a sticky/stuck VB spool can cause it, as can damaged friction material. The fact that you had some good shifts after your initial repair suggests it isn;t friction material involved, which leaves the potential for VB rebuilding as a solution, beyond just replacing the solenoids. I'm betting you have a BIG chance for success with your solenoid replacement!

ps. To answer your question in the PM, the Diary 4R70W sold for $2K. But it had all new internals and a cast aluminum pan. Cost of a rebuild would be dependent on upgrades and parts replaced.

 

[mnealuf]

Update: I think it is fixed. I replaced the 1-2 accumulator cover with updated one and the solenoid pack. I drove the truck about 30 miles tonight as well as a ton of stop and go (1-2 shifts) in my neighborhood and no codes...shifts smooth and nice..best since I have owned it. I am crossing my fingers because there were times last week it would go a couple miles and not throw a code then would so hence my extended test drive. I found an easy way to install 1-2 acclamator. I could use a 5 inch "C" clamp and hold the cover and easily install the snap ring...I tried to taker a picture but not sure it it is clear or not in picture.

 

[mnealuf]

The truck has been running/shifting good for ~2 wks. Yea. Tonight as I was rounding a curve about 40mph I went to accelerate slightly and it either shifted out of OD and down a gear and/or slipped terribly for about one second duration. Either grabbed or up shifted and was fine. No OD code.........is this a sign of looming trouble or just a occasional goofy lack of logic ? Is the 4R70W typically pretty good at knowing what gear it wants? I am so ready to sell this thing...anyone wanna buy a truck!!!!

 

[mnealuf]

ttt, anyone?

 

[Glacier991]

I'd assume something just hung up. How is your fluid ? Do not panic yet.