[rk0982]

I have a 2001 taurus and I changed the transmission fluid in it a few days ago. I dropped the pain replaced the filter and fluid and when I went to drive it the overdrive did not work and the transmission indicator light on the dash would flash. Everything worked fine before i changed the fluid. I went to a transmission shop and they hooked up a scan tool it has the code p0734. Has anyone had this problem before?

[Dominick]

Did you make sure the filter was seated
P0734 Gear 4 Incorrect ratio

[rk0982]

yes i did I even dropped the pan again to make sure. Do you know what else it may be thanks

[Dominick]

Just a guess you may have knocked a wire loose on your shift solenoids when you changed the filter.

[rk0982]

do the wires have a plug on them.

[Dominick]

If I remember correctly the do.
Before I retired our trans man had replaced some of the solenoids so the must have.

[rk0982]

ok thanks do you know anything else it could be i didnt want to drop the pan again and have to replace the fluid

[Dominick]

I thought I had a break down of that trans but don't
would just check all your plug in wiring on the outside of the trans before dropping it again.

[Dominick]

You have muliple solenoids in it they are simular but not the same check the wiring to them

[rk0982]

ok thanks ill check them and let you know what i find

[Dominick]

Those are mounted in the valve body so I doubt if you knocked a wire off
Sorry.

[phantom]

P0734SSA, SSC, or internal parts4th gear failure.Incorrect gear ratio while commanding 4th gear.Incorrect gear selection depending on condition mode and manual lever position: see solenoid operation chart. Shift errors may also be due to other internal transaxle concerns (e.g., stuck valves, damaged friction material) (TCIL flashing, California only).

[rk0982]

ok thanks

[rk0982]

I went and checked the connectors on the transmission and I couldnt find any that are lose. Is there anything else i can look for.

[Poppy]

Sorry That I can't contribute more, but one of the possiblilities listed by that code is the transmission range sensor. You may want to look at the connectors to it.

[rk0982]

I appreciate the help do you now were the transmission range sensor is located

[Poppy]

The problem with the trans-axle engines is that everything is so darn cramped in there.
Fortunately for me I have not had to deal with it, but I believe that it is on top of the transaxle.
IIRC Mark_V had posted a picture of it on a different site that is no longer in existence.

You may goto www.rockauto.com or autozone.com to see what it looks like.

[rk0982]

ok thanks

[Pecos Slick]

Make sure you removed the old filter gasket/O-ring, if not it could be sucking air.

[Boghog]

Now that all the wanna-be’s have given you their opinions let’s get down to the real business.

You neglected to provide the engine size ( 3 available 3.0L’s) or transmission model (2 different models available)

This PCM (engine computer) monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:

Torque converter slip ratio = A x C/B

A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from Engine Control Module
C: Gear ratio determined as gear position which TCM supposes

If the actual gear position is higher than the position (4th) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction. P0734 is detected when A/T cannot be shifted to the 4th gear position even if electrical circuit is good.

Possible causes of this code are as follows:
- Low transmission fluid level ---Should have been corrected during the trans service

- Dirty transmission fluid ---Should have been corrected during the trans service but if the fluid was really dirty (as in it’s never been changed before),new fluid could have washed away sludge that was taking the place of a worn part. In this case an overhaul or replacement may be required.

- Shift solenoids ---highly unlikely after a fluid change, but possible as stated in the above description.

- Transmission mechanical problems ---This could be an issue. The PCM monitors revolution ratio of the forward clutch drum revolution to the differential gear case revolution when the following monitoring conditions are met. If the revolution ratio is below 0.6 or 1.25 or more, the PCM determines that there is a malfunction.

This is a continuous monitor (CCM). The MIL does not illuminate. The AT warning light illuminates if the PCM detects the above malfunction condition during the first drive cycle. Was the PCM cleared of codes or the battery disconnected ?
Freeze frame is not available. A pending code is not available. The DTC is stored in the PCM memory

- Transmission hydraulic control circuit--- These are the most like causes:
• ATF level low --- should have been corrected with the fluid change
• Deteriorated ATF --- should have been corrected with the fluid change
• Shift solenoids A, B or C stuck
• Pressure control solenoid stuck
• Line pressure low
2-4 brake band slipping
3-4 clutch slipping
• Forward clutch slipping
• Control valve stuck (Bypass or 3-4 shift valve)
• Oil pump malfunction
One more possibility could be the VSS (vehicle speed sensor), but this should be looked at for the possible torque converter slip as stated above.

Without have the proper diagnostic tools and knowledge, this diagnosis may be well out of your reach. My suggestion would be to consult with a transmission specialist at the dealer level or an independent shop.

Oh and definitely do what Pecos suggested, I’ve seen many people double the o-ring on the filter and create all kinds of problems.