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View Full Version : 1994 4R70W - transmission of doom



potshotscott
08-01-2017, 10:01 PM
Well, TSB-95-8-3 is coming back to haunt me. Again. 67495 Odd shift going from 1st to 2nd as though it had a shift kit in it or a Jmod. Third gear shifts went whack yesterday. As I read this I feel as though I have two options.

1. Buy the 1995 PCM and transmission at the wreckers for a grand total of $280 plus a core charge
2. Buy the 1995 PCM and 2001-2002 transmission at the wreckers for about $350.00 plus core and then mod the TCC and a few other small items.

It's clearly making metal. Which route would you go? I don't have the time or the money to rebuild the current unit or I'd be up for an awesome learning challenge.

One other lame question - can I reuse my fluid if I strain it several times and run a clean magnet through it several times? This fluid isn't but a year old and while it's not really expensive it's not cheap either. I know it's a cheap-arse question.


67494

MadMikeyL
08-01-2017, 10:12 PM
The 99+ trans is a way better starting point than the 94 or 95 trans. I wouldn't waste my time putting another 94/95 trans back in. And no, you can't re-use that fluid, unless your goal is to see how quickly you can kill the new trans.

KMT
08-01-2017, 10:14 PM
Just my opinion, but any straining/filtering that might even come close to being effective would cost way more than new fluid - you'd be amazed at what can exist after the goings on seen in the pan at the moment, that you both can't see and can't remove casually. Feel your pain, but not worth it, I think.

potshotscott
08-01-2017, 11:49 PM
Fluid is going to the recyclers at the dump. Going to source a 98-02 unit tomorrow and get the 95 PCM. Mod the trans harness in the car and call it macaroni.

KMT
08-01-2017, 11:53 PM
...and call it macaroni.

👍

G'luck w/it. Should be slick when done.

Ken

potshotscott
08-03-2017, 01:23 AM
Bought a 2002 unit at a wreckers that has about 60K on it. Is a recent arrival to the yard. Got it for $300.00 without a requirement for core. I think I'm going to keep my 94' unit and rebuild it some day. The service advisor at my local dealer is actually looking into a PCM flash for my LX OBD2 PCM. Might be able to get more life out of it yet!

Tim Groth
08-04-2017, 10:05 AM
Also make sure you flush your lines and cooler while at it...I flushed my converter also when I did my last rebuild and had the same crap in the pan. Last thing you'd want is garbage killing the new trans.

-Tim

scskydivin
08-04-2017, 10:46 PM
Subscribed. Looking forward to see how this works out, should you decide to chronicle this build/swap.

potshotscott
08-05-2017, 11:16 AM
The last time I did this I got an 02' Mustang unit for the SC from a wrecker with 3000 miles on it. No joke - 3000 miles. This time around I need the 2002 4.6 trans and they literally had lemons. The first trans I took home looked okay until I pulled the pan and half cup of water came pouring out. Not to mention it was an 03 unit that didn't have the gearing for VSS on the output shaft. The second unit they tried to give me was an 02 with 150K on it. It had a broken tail shaft housing and yep, you guessed it - they pressure washed it before they tried to give it to me. I quickly searched their website on my phone and found a 95 LX unit with 123K on it that I asked them to get down off the shelf. Needless to say for convenience sake (and because all their late model units were junk) I took the 95 unit home. I got it installed last night. Need to put the final exhaust section back on, torque the drive shaft bolts and fill it with fluid/test.

One interesting thing and I'm wondering - I could turn the engine by hand to get the old converter out. I could NOT turn the engine by hand but instead had to engage the starter to turn the flywheel enough to put all the nuts on. Anyone have any ideas? The only thing I can think of is I don't have the torque converter on correctly??? I have the Ford shop manual and can read/follow directions in sequence but failed to look at the orange dot on the converter/flywheel. 75% chance I failed to mate them. However - this is not the original TC.

Thoughts?

TBirdJKC
08-05-2017, 11:25 AM
Sounds like its binding from the tc not being seated. I had similar trouble and broke the input shaft from the pressure. I didn't even spin the engine yet. It just didn't feel right.

potshotscott
08-05-2017, 11:38 AM
Okay - not wanting to risk anything I'm going to pull the transmission back out this morning to take a peek. Hopefully I can get this thing running tonight.

KMT
08-05-2017, 01:23 PM
Okay - not wanting to risk anything I'm going to pull the transmission back out this morning to take a peek..

Did you sanity check the snout size on the replacement TC with the hole in the crank/flywheel just to be safe? Did you confirm the TC was fully plunged and engaged into the trans before mating to the engine? Spin and push...

potshotscott
08-05-2017, 01:45 PM
So TC size into the engine side looks great. I believe I failed to seat the TC correctly on the input shaft when I put it in last night. I'm trying to pull it out this morning with the TC still in the car but its jammed pretty good and I'm pretty tired from getting it in by myself last night with a single floor jack. As I was getting things set on the jack the TC slid out of the bell housing. I thought I had it mated correctly - must have been wrong.

Another awesome fun thing is that now my SC has the "brake!" light on and the rears feel like they're dragging. Hopefully all I need to do is adjust the pull cable.... If I wasn't going to Houston on Monday for work I wouldn't be so stressed. If I had more money in the bank I'd haul the LX to the wreckers and consider selling the SC. Tinkering is fun, full tilt mechanic stuff every year (balancer, transmission, coolant flushes) is getting old. If I thought I could get half of what I've got in my SC out of it I'd be tempted to list her on Craigslist today.

davec73
08-05-2017, 01:57 PM
[QUOTE=potshotscott;1111577]So TC size into the engine side looks great. I believe I failed to seat the TC correctly on the input shaft when I put it in last night. I'm trying to pull it out this morning with the TC still in the car but its jammed pretty good and I'm pretty tired from getting it in by myself last night with a single floor jack. As I was getting things set on the jack the TC slid out of the bell housing. I thought I had it mated correctly - must have been wrong.

Another awesome fun thing is that now my SC has the "brake!" light on and the rears feel like they're dragging. Hopefully all I need to do is adjust the pull cable.... If I wasn't going to Houston on Monday for work I wouldn't be so stressed. If I had more money in the bank I'd haul the LX to the wreckers and consider selling the SC. Tinkering is fun, full tilt mechanic stuff every year (balancer, transmission, coolant flushes) is getting old. If I thought I could get half of what I've got in my SC out of it I'd be tempted to list her on Craigslist today.[/QUOTisE]

are your thunderbird your only mode of transportation? If so that sucks 25 year old cars that were advanced for there time at a bear to maintain much less expect them to pull the duties of a daily driven vehicle. may be time to buy a taurus Altima Camry for daily use man😉

davec73
08-05-2017, 01:59 PM
the torque converter should click in twice while seating it I believe.

KMT
08-05-2017, 02:10 PM
are your thunderbird your only mode of transportation?


My '90 Anny was (since 2008) until last Nov. when it needed some body work. I picked up another vehicle (2002 Windstar; 3.8L) in the mean time and now the SC mostly just sits. Runs fine, but I got nervous about it being my only transportation. It's never left me stranded, tho.

potshotscott
08-05-2017, 02:17 PM
We have a Sienna van and two '94 Birds. One is a Super Coupe and on is an LX. Wife is out of town all week. Usually its not this much of a bother. Got the SC back in good order though with a simple parking brake adjustment.

Now gotta figure out the LX. I've got all the trans bolts out and everything is unmounted EXCEPT the torque converter. I can't get the trans down. Might need to turn the crank with a 3 foot breaker bar so I can get the TC nuts off. It should come out then. I should have known better last night when I needed to use the starter to turn the TC to put all the nuts back on.... shame on me for being impatient.

davec73
08-05-2017, 04:36 PM
We have a Sienna van and two '94 Birds. One is a Super Coupe and on is an LX. Wife is out of town all week. Usually its not this much of a bother. Got the SC back in good order though with a simple parking brake adjustment.

Now gotta figure out the LX. I've got all the trans bolts out and everything is unmounted EXCEPT the torque converter. I can't get the trans down. Might need to turn the crank with a 3 foot breaker bar so I can get the TC nuts off. It should come out then. I should have known better last night when I needed to use the starter to turn the TC to put all the nuts back on.... shame on me for being impatient.

hopefully you can just seperate the tc3 and flex plate spin the tc3 and it will go into place.

MadMikeyL
08-05-2017, 10:54 PM
If all the bolts are out of the trans, support it with a jack and pry the trans back an inch or so off the motor, and that should allow the motor to turn over freely. At this point though, if you bolted the trans all the way tight with the TC not seated, you have at the very least damaged the front pump, and possibly damaged the converter, and possibly the whole trans.

potshotscott
08-06-2017, 01:06 AM
I never started the car. I separated the TC and the trans today and then got it put back together correctly. I need to put the exhaust back on the car and then fill the transmission with fluid. I'm no expert but I don't think I've ruined anything. Crossing my fingers for tomorrow.

potshotscott
08-06-2017, 02:33 PM
Well as luck would have it I did NOT ruin anything. Put 13 Quarts of fluid in her and took it out for a spin. Shifts VERY nicely. Wished I had a method to check PCM code version - will look into that later. Checked fluid when I got back from the test drive and it appears as though it's full at 13 Quarts to the "hot" line (I did take it out on the freeway and open it up a little bit too).

Pretty happy to have this beast back on the road for my daughter. Now with trans, filter and fluid I'm into this car $1000 including purchase price. It's so quiet that now I am reminded that this car might need rear wheel bearings or some differential work since there's a very small low frequency whine back there. When that/those go perhaps it will be time to send it off to pasture.

Thanks for the help all

Goldenhands57
08-21-2017, 06:04 AM
Well as luck would have it I did NOT ruin anything. Put 13 Quarts of fluid in her and took it out for a spin. Shifts VERY nicely. Wished I had a method to check PCM code version - will look into that later. Checked fluid when I got back from the test drive and it appears as though it's full at 13 Quarts to the "hot" line (I did take it out on the freeway and open it up a little bit too).

Pretty happy to have this beast back on the road for my daughter. Now with trans, filter and fluid I'm into this car $1000 including purchase price. It's so quiet that now I am reminded that this car might need rear wheel bearings or some differential work since there's a very small low frequency whine back there. When that/those go perhaps it will be time to send it off to pasture.

Thanks for the help all

Your 4R70W innards will fit and are an improvement for the AOD that are used in the 89-91 SC (and other birds as well). 4R70W have the wider 2" overdrive drum and other changes that will help the issues with the AOD. Transmissions are not that hard to overhaul, mostly a good overhaul manual, a place to wrestle with it and the best quality snap ring pliers you can find.
Using Alta "red" frictions and steels the AOD with 4R70W innards becomes a decent transmission. The strongest version of the 4R70W is from the F-150. It's only a matter of time before my 91 has overdrive problems and I'll be looking for that 4R70W to swap in the better parts. Also.. the Torque Converter and input shafts are totally different between the two automatics. The AOD has a weak shaft-in-shaft design (two seatings on the Torque Converter installation, 4R70W is one seating like most other Torque Converters are..AOD's are the oddball).
Your 4R70W has value as a improved swap core to the AOD. The AOD body accepts all of the 4R70W innards with no modification. Use the AOD valve body with a shift kit and the same TV settings determined by pressure gauge, it'll be a good unit for many a mile. You are very fortunate you did not fracture the cast iron front pump gear tabs. T/C snouts also have been made different diameters in Fords from time to time. C6 460 used in Lincolns are not the same as T-Bird or Mercs. Ask me how I know that from first hand experience!$$!

potshotscott
08-21-2017, 04:23 PM
I was going to keep the old core but I have a 3.8 SC and a 92 5.0 LX of which none are compatible. The 5.0 has a dead transmission and I just replace/rebuild a 3.8/5.0 4R70W for it when the time frees up to work on Mustang that's been sitting for a while now. If you're anywhere near Oregon I'm about to list the 4R70W core for cheap on Craig's.