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Transmission OBD P0733 and P0734
On the way home from work today, I made an easy acceleration from a stop sign and had big problems when it should have shifted from 2nd to 3rd. It wouldn't shift up and just kept slipping. The tach swept from 2000 to about 2800 while it did this. I threw the automatic into "2" and even though it revved higher than I would like because of fuel prices, it steadied out. I only went another half mile and the engine light came on. I pulled over andhooked my trouble code reader up and it had two codes, P0733 and P0734. 733 is "Gear 3 Ratio Incorrect" and 734 is "Gear 4 Ratio Incorrect".
I only had a couple miles left to get back to the house at that point so I kept the shifter on 2nd and went home. I checked the xmsn fluid level before I shut down and it was in the "Hot" section of the dip stick like it should be. I have two questions about this. First, what causes gear 3 and 4 to suddenly forget their ratios after 15 minutes of driving? Second, how do I fix it? Can an aftermarket computer fix the ratio in a 45RFE? '02 Dakota SLT Quad Cab, 4x4, 4.7 |
RE: Transmission OBD P0733 and P0734
If you are still under warranty I would get it to the dealer pronto for a fix. If you not sure of a self fix, that's what I would do. Sounds like a PCM glitch.
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RE: Transmission OBD P0733 and P0734
I second that but you may have more luck in the gen 2 room.....
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RE: Transmission OBD P0733 and P0734
depending on the mileage it may just need to go into the shop for a fluid change and retightening of the bands
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RE: Transmission OBD P0733 and P0734
By aftermarket computer I assume you mean a programmer which is not yet available for our 3rd gen. trucks. Superdak's suggestion of of a fluid/filter change and band adjustment fixing this is unlikely but possible. Have you had any problems before this of trans slippage? Bring it in and have them check it out. Give us an update when done.
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RE: Transmission OBD P0733 and P0734
is it for the 02 in the bottom of the post?? if so, isent a programmer avalable for it and aint it a 2nd gen?
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RE: Transmission OBD P0733 and P0734
Theory of Operation:
The transmission system uses two speed sensors, one to measure input RPM and one to measure output RPM. These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through the following checks: 1) Once in a particular gear, if the gear ratio varies from the correct gear ratio, the corresponding in-gear trouble code is set (DTCs P0731–36). 2) An excessive change in input or output speeds indicating signal intermittent may result in the DTCs P0715 and/or P0720 being set. 3) If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed sensor when at a stop in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the output speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause the DTC P1794 to set. 21 - 478 AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS ND And FYI, the RFE transmission (like 42RFE, (5)45RFE) don't have bands to adjust. |
RE: Transmission OBD P0733 and P0734
Wow, I didn't expect this much helpful information so soon. Sorry for posting a Gen 2 issue in a Gen 3 area. I'm a first timer and I didn't realize I was still in this area. The '02 listed at the bottom of the first post is the Dakota in question. Would anyone suggest a particular programmer to fix this? I've never shopped for one of those yet so I don't know the brands.
I'm going to start troubleshooting tonight by unattaching the battery first. Maybe that will affect the computer. I suppose checking for loose connections to the sensors will be easy as well. I don't know where to look at the moment but a Hayne's manual should show that. I'll post the results. B |
RE: Transmission OBD P0733 and P0734
Just returned from my first test. It failed. I disconnected the battery for about ten minutes, hooked it back up and took a test drive. 1st to 2nd shifted just like always but when I hit the normal shift point to go to 3rd, I felt like it shifted to lower gear if anything. It was not much of a difference but there was an attempt at changing gears. A simpler way to put it would be to say the ratio was very close to 2nd gear but it was not still in 2nd. Whether I took off nice and easy or punched it, the outcome was always the same. 1st to 2nd was fine but after that the tach would just keep variably increasing.
I found no loose terminals on the transmission. My cheap Haynes manual had no pictures of any speed input on the tranny. I think I read somewhere that they are wired to the rear axle on some models. A sanity check on that would be helpful. I'll keep updating my progress. Now I'll start shopping for a programmer. B |
RE: Transmission OBD P0733 and P0734
I gave in and called the local Dodge dealer about this. They towed it over and unbuttoned the pan. They called me a few days later and told me the accumulator in the transmission had to be replaced. Now it drives like it always did before it happened. I'm doing a drain and flush on the transmission today so all the crap that caused this won't affect anything else. A filter swap will be happening today as well.
B |
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