DODGE RAM FORUM banner

1 - 7 of 7 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I could use some advice on this. I'm going on a third week now dealing with this issue and I've searched this forum as much as I can about the error codes I got, what repairs people have made in similar situations, and even some horror stories. I can't find an exact replica of what I'm presently experiencing, so it's time to make this post. It's a long story...please bear with me if you want.

'08 Ram 1500 ST 5.7L Hemi, 160k+ miles, Looked to be original transmission.

Two Saturdays ago, I was driving into work and my CEL came on. The truck also started driving like it was down a cylinder or two (came to find out later that was Limp Mode for the transmission). I didn't have time to get to it right away, but I took it to Advance the next morning and found it had tripped the P0750 - 'Shift Solenoid A Malfunction'. After the clerk and I did a quick search, we discovered you have to purchase the entire solenoid pack as a kit, and have to drop the pan to replace it. Oh, here we go, I thought. :i_rolleyes:

I am typically a DIY type, but when you start talking about transmissions and dropping pans, I don't have the knowledge or tools to tackle it alone. I decided to take it to my go-to mechanic since he'd done some great clutch work on my last truck. He was very familiar with the problem and felt it was pretty common with 3rd Gen Rams. He also warned me that buying that kit and replacing the solenoid pack, fluid, and filters only had about a 50% success rate with his former repairs depending on how much metal was loose in the transmission. His suggestion was to prepare for the worst, and get a rebuilt transmission put in if there was a lot of excess metal.

Now being the DIY type, I had to take that with a grain of salt. I gave the go-ahead to pull the pan, but of course I wanted to see for myself and decide from there. Needless to say, it didn't look good even to my amateur eyes. The hindsight was I should have had him service the thing when I bought it, but oh well. Live and learn. The previous (also first) owner probably did the majority of the damage. The mechanic recommended a Jasper rebuilt - probably the best after market transmissions out there with the best warranty offer. Not cheap, but I researched them myself comparing them to many others and grudgingly agreed to take it in the shorts.

One work week and a rental car later, my baby was ready to hit the road again with her new transmission. After an exceedingly long back and forth with the credit card company thinking it was a fraudulent purchase I was trying to make, I took my truck and ran a few errands in town. It was shifting great, and felt almost new again - that new transmission really made that Hemi want to jump up and run! No issues, until...

I was headed out of my small town to my GF's small town, and not but a mile out of town as I was picking up speed on the highway, BAM! CEL back on! Turned around and high tailed it to the shop; closed already. Trip cancelled! Went to Advance - this time it gave two codes: P0934 for Hydraulic Presure Low, and P0740 for the TCC. Ay caramba! I was back at the shop bright and early. My mechanic thought that it may just be some of the connectors weren't as clean as they should be and probably got some debris in them during the transmission change. He went through each one associated with the transmission and cleaned them off well. He reset the codes with his computer. At his request, I test drove it on the highway for about 10 miles. The light did not return. Again, I started for my GF's place a little later that day, and this time (on the same road as the test drive even) not but 5 miles from town, CEL again!

Returning to the shop, same codes P0934 & P0740, he felt that it was possibly a defective sensor that came with the new transmission. To test, he changed it out with the one from the old transmission and reset the codes again. He set me loose and told me I was basically a guinea pig driver now, and to keep him updated on what happens. In the mean time, he would order a new sensor for a permanent replacement. This time I made it all the way to my GF's place, 70+ highway miles with no light returning. I really thought it was all over, until the next morning...

Headed to work from her place, the dreaded CEL popped back on after about 20 miles on the road. I knew I didn't have time to go to my mechanic or even one closer to where I was, so I cautiously continued while feeling/listening for any trouble, watching my Tach, and watching the Temp gauge. I observed nothing abnormal all the way into work. I called my mechanic from work and told him I'd be in in the morning. :SHOCKED: Returned home after work paying close attention to everything. Other than the light, no indications of trouble.

He and I both did some research overnight, mine of course included scouring this very forum for answers. He even called Jasper to see if they'd heard of this issue before. We both came up with a few possibilities, most of which had to do with the PCM and some of the parameters being too narrow when transmission replacements occur. Also, it could be a voltage or resistance issue on one of the wires or connectors itself. He went ahead and put the new sensor on as planned, and then checked the voltage to the connector on the transmission. He did not have the special tool/computer that the documentation said was required to check resistance, or the PCM parameter issue. But, he did run a flash/reset of the PCI(?) before resetting my codes. Lastly, he told me that if this didn't work, he may be sending me to a dealer for a diagnosis, because it's beginning to look like a computer issue to him. In my head, the phrase 'dealer service' = $$$.

So, after a day at work, the CEL returned on the drive home that evening. That is where I presently stand with this issue. I can't go back to him since it is the weekend, but I'm afraid of ending up at the nearby dealer Monday. Yeah, it's just for a diagnosis and estimate, but it has to be fixed, right? I just fear I won't have my truck again for another week, and that I'll have to spend three more digits on this job (which WON'T be covered by the Jasper warranty if it is indeed a PCM issue) AND another rental car.

So I am looking for anyone that can offer input on my situation that might keep me out of the dealer shop. I don't care if I was a fool at this point to get the new transmission or not, but should I see another mechanic for a second opinion on this? Are there anymore tricks we haven't tried that might fix this? I am really looking for a direction to go that doesn't involve the word 'dealer' and might, just maybe, be covered by Jasper's warranty. :smileup:

Anybody?
 

·
Registered
Joined
·
2,442 Posts
Your main problem is the P0740 (TCC Out of Range). P0934 is Line Pressure SENSOR Low (not line pressure low), and is usually a sensor or wiring problem. P0934 means the PCM sees a voltage level from the line pressure sensor that is lower than it should ever be (even at zero line pressure). Also, I don't believe P0934 will light the CEL (or put you in limp-in). So P0740 is what's causing your CEL, although that shouldn't put you in full limp-in either (it should simply disable your Torque Converter Clutch [TCC], which can eventually cause the trans to overheat on a long trip).

P0740 means one of two things: Either the TCC does not engage (when commanded by the PCM), or it takes too high a duty cycle (in the solenoid that controls the TCC) to fully engage the TCC. In the first case, the culprit is usually the torque converter itself (bad TCC or bad seal). In the second, the problem is likely that the bore for one of the TCC control valves (in the pump) is worn oversize, allowing leakage which then causes the PCM to have to crank the solenoid duty cycle up too high.

So overall, my guess would be that either the pump or converter in your new trans is bad. Time for Jasper to replace them (or the whole trans) under warranty.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3 (Edited)
Thank you so much. This will help tremendously. I should have clarified - the new transmission has never entered Limp-In mode (knock on wood). That problem went away with the change. I'm going to pass this along to the mechanic and hopefully we can get it done fast.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #4 (Edited)
Just an update: After discussing your findings between myself, the mechanic, and Jasper's "technicial expert", Jasper rep felt because it was code P0740 and not P0741 that it was a defective solenoid with the new transmission. Shipped us a brand new MOPAR solenoid pack. Went in. Light came back later that day.

So, this is definitely correct, and what I will be not-so-politely telling Jasper to send me:
Time for Jasper to replace them (or the whole trans) under warranty.
Ugh.
 

·
Registered
Joined
·
2,442 Posts
Just an update: After discussing your findings between myself, the mechanic, and Jasper's "technicial expert", Jasper rep felt because it was code P0740 and not P0741 that it was a defective solenoid with the new transmission. Shipped us a brand new MOPAR solenoid pack. Went in. Light came back later that day.
Well, for starters, P0741 is not a valid fault code for an RFE transmission (it will NEVER set that code). And if the solenoid were bad, it would also set a P0750 code (which is why I didn't suggest the solenoid as a possible cause).
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
Well, for starters, P0741 is not a valid fault code for an RFE transmission (it will NEVER set that code). And if the solenoid were bad, it would also set a P0750 code (which is why I didn't suggest the solenoid as a possible cause).
Makes sense. I knew you were probably right and they were trying to get out cheap. Oh well, didn't work!

They have dispatched a replacement transmission assembly. So we've convinced them it's a defective TCC that came with the first one. Here's hoping this is the end! Goes on Tuesday...will post an update then. At least they are standing behind their product and honoring the warranty.

Thanks again for your guidance, TransEngineer!
 

·
Registered
Joined
·
9 Posts
Discussion Starter #7 (Edited)
Replacement transmission for the replacement transmission :doh: has been on a few days now, and seen more mileage than the first one did. Still no light. I am feeling more confident each day that I'm through the wilderness finally.

The mechanic and I are eagerly awaiting Jasper's report from the dissection of the defective unit, so we can tell them to trust the computer code a little better for the next customer this happens to. Any DIYer or mechanic knows first hand, even new parts can be defective!!! On a side note, the warranty claim to pay for all of this work will remain pending until their 'findings' are complete. Let's see if they really do back their product & support techs' opinions.
 
1 - 7 of 7 Posts
Top