4R70W Intermittent rough 1-2 shift

[Canadastang]

I've got an '03 Town Car with about 60k miles, car works great, but intermittently, the transmission will have a rough 1-2 shift. Only happens when the trans is heated up and only about 10-20% of the time.

Basically it just kind of 'hangs' but doesn't slip between 1 and 2 for a second on upshifts and engages 2nd rougher than usual. The other 80% of the time, that shift is great and almost imperceptible.

The trans works great otherwise and has zero issues with shifting or drivability in any other gears.

I've done a pan drop and refill three times with MC Mercon V (changed the filter too) and added lubegard red. Also installed a new MLPS/range sensor. Hasn't made any difference.

I doubt this is a 1-2 accumulator or spring issue since it only happens intermittently.

Any ideas?

 

[SatinSilver]

Hmmm, you've already done what I would have recommended. I would send a pm to "clinebarger" since he's a transmission expert and builds them for a living.

 

[clinebarger]

Any stored or hard codes stored in the PCM?

Engine Performance issues can cause extended & harsh shifts because the engine isn't make the power it should or the calculated load values are off in the PCM.

Intermittent issues with the throttle position sensor or the Mass Airflow sensor would cause symptoms like yours, These 2 are the sensors the PCM uses to calculate load.

Clogged air filter, Dirty mass airflow, Plugged fuel filter, Secondary ignition & partially plugged catalyst are all possibilities.

It may be time to have a competent powertrain technician look at it! Unless you have a way to record/log live data?

 

[i_hate_autofraud]

Actually shift accumulators can cause intermittant shift problems.

See if TransGo has a shift kit for your transmission. Search for reviews and other comments, you never know what you find!

 

[clinebarger]

Originally Posted By: i_hate_autofraud


Actually shift accumulators can cause intermittant shift problems.

See if TransGo has a shift kit for your transmission. Search for reviews and other comments, you never know what you find!


A 4R70W has 2 opposing 1-2 Accumulator Springs, One breaking would cause a softer 2nd shift all the time, The other will cause a harder 2nd shift all the time.
Accumulator bore and or piston being tore up would cause a line pressure leak that usually rears it's head as delayed forward engagement, At 60,000 miles....I doubt this is an issue.

Most Trans Go products are consumer grade junk at best, There are some exceptions.....Like the 4L65E SK kit, 700R4 TV kit, Allison 1000 SK & SK-jr. But for AOD/AODE/4R70W units.....Do Not use a Trans Go kit!

 

[Canadastang]

Originally Posted By: clinebarger
Any stored or hard codes stored in the PCM?

Engine Performance issues can cause extended & harsh shifts because the engine isn't make the power it should or the calculated load values are off in the PCM.

Intermittent issues with the throttle position sensor or the Mass Airflow sensor would cause symptoms like yours, These 2 are the sensors the PCM uses to calculate load.

Clogged air filter, Dirty mass airflow, Plugged fuel filter, Secondary ignition & partially plugged catalyst are all possibilities.

It may be time to have a competent powertrain technician look at it! Unless you have a way to record/log live data?


No stored or hard codes in the PCM; Fuel filter is a new motorcraft with less than 5000 miles on it; new air filter; cleaned the MAF; plugs are new motorcraft platinums.

I've tried disconnecting the battery a couple of times, made no difference, but the emissions monitors do reach readiness quite quickly.

The car runs like a top, idles like silk, and gets 20MPG in a 50/50 mix of city/hwy driving, so I have a hard time thinking it's an engine issue, although I suppose it's possible.

I've got an Autel 519 and the Forscan app, so I can do some datalogging later this week when I get a chance.

Anything in particular I should be looking for?

 

[Kuato]

Originally Posted By: clinebarger
Originally Posted By: i_hate_autofraud


Actually shift accumulators can cause intermittant shift problems.

See if TransGo has a shift kit for your transmission. Search for reviews and other comments, you never know what you find!


A 4R70W has 2 opposing 1-2 Accumulator Springs, One breaking would cause a softer 2nd shift all the time, The other will cause a harder 2nd shift all the time.
Accumulator bore and or piston being tore up would cause a line pressure leak that usually rears it's head as delayed forward engagement, At 60,000 miles....I doubt this is an issue.

Most Trans Go products are consumer grade junk at best, There are some exceptions.....Like the 4L65E SK kit, 700R4 TV kit, Allison 1000 SK & SK-jr. But for AOD/AODE/4R70W units.....Do Not use a Trans Go kit!


Agree it could be a spring...had similar problems on a Grand Marquis and although the trans was different, installing a shift kit/heavy duty spring made it shift like new.

 

[Colt45ws]

Agree, it could be something in the PCM. I would datalog load, rpm, speed, EPC pressure commanded, gear commanded.
Youll be able to see pretty quick if its something the computer is doing. The time from gear commanded to an RPM drop should be pretty consistent. If it takes longer when the hard shift occurs, its in the trans.

And never use a TransNO kit in these. If anything do a Jmod. Ive done Jmods to 8 of these transmissions. I have a good setup that makes quick shifts that dont slam. The last car I did the owner was very particular that the trans didnt shift roughly after I finished and hes very happy with my configuration.

Jmod parts minimum
Sonnax
76948-09 pressure regulator [std. pressure] (not needed for 09+ transmissions) $15
76948-29k OD servo regulator $30
76948-02k Boost valve kit $20
Superior K092 separator plate $40
Ford
1W7Z-7D100-AB gasket $2
1L3Z-7C155-AA gasket $2
Fluid (Mercon V or LV dependant on year) $80
Motorcraft FT105 Filter $19
Hole #1 (Intermediate clutch feed post Accumulator) #20 drill
Hole #2 (Intermediate clutch feed pre Accumulator): 7/64"
Hole #3 (Intermediate clutch exhaust) #15 drill
Hole #4 & #5 (Direct clutch feed): #33 drill
Hole #6 (Direct clutch exhaust): #20 drill
Hole #7 (Reverse servo feed for Manual 1st): #43 drill
Hole #10 (Reverse feed): #43 drill
Hole #9 & #11 (Forward clutch feed): 1/8"
For More aggressive instead do:
Hole #2 (Intermediate clutch feed pre Accumulator): #33
Hole #4 & #5 (Direct clutch feed): 1/8"
Hole #7 (Reverse servo feed for Manual 1st): 3/32"
Hole #10 (Reverse feed): 3/32"

 

[FastLane]

Do you know of any place that you can buy a valve body with the j mod already done to it?

 

[JustinH]

Originally Posted By: FastLane
Do you know of any place that you can buy a valve body with the j mod already done to it?


There are some guys on the ford forums that will drill the separator plate for you as a service, but you need to return your stock separator plate to them.

It has been about ten years since I have done this service, but dropping the valve body, and replacing the plate is not a hard job.

I even replaced some accumulator pistons and springs in my thunderbird in the driveway using a bottle jack and a piece of wood to sink the piston into the bore.

If you have a newer car you probably won't even need the new accumulator pistons, but some people remove one of the springs for a firmer shift.

I believe there are two paper gaskets between the separator plate and the valve body that need to be replaced when you take it apart.

 

[i_hate_autofraud]

Seems Ford and GM have lots in common when you need to use drills as small as #43, etc to get the correct
oil flow for proper transmission function! Like it's gotta be on purpose!

Sonnax has drill guide info for other transmissions with similar problems.

 

[Colt45ws]

Originally Posted By: JustinH
Originally Posted By: FastLane
Do you know of any place that you can buy a valve body with the j mod already done to it?


There are some guys on the ford forums that will drill the separator plate for you as a service, but you need to return your stock separator plate to them.

It has been about ten years since I have done this service, but dropping the valve body, and replacing the plate is not a hard job.

I even replaced some accumulator pistons and springs in my thunderbird in the driveway using a bottle jack and a piece of wood to sink the piston into the bore.

If you have a newer car you probably won't even need the new accumulator pistons, but some people remove one of the springs for a firmer shift.

I believe there are two paper gaskets between the separator plate and the valve body that need to be replaced when you take it apart.

Yeah, its simple. There are howtos on youtube, though I dont remove accumulator springs like most people. It makes it too hard of a shift in most cases and its a huge PITA. If someone came to me wanting a aggressive shift, I would put in the higher pressure sonnax pressure regulator; my CVPI has that and it would drop second like a sledgehammer, scratching both rear tires. I actually pulled a bunch of pressure out in the PCM because it was too aggressive.
The advantage of buying the Superior K092 separator plate is
#1 its thicker than stock and this can help. Some times the direct clutch accumulator can hammer a crack into the plate, causing issues.
#2 you have your stock separator plate if you dont like it. You can't order a lone separator plate from Ford; theyll sell you a whole valve body at minimum.
And yeah, I can give you the information for someone that builds 4R70s and sometimes has built valve bodies available.