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Discussion Starter #1
You can see the mods I have in my sig.... At around 104,000 my torque converter started slipping so took it to the dealer and had it replaced. It's been two weeks and this one is slipping and making the trans over heat therefore going into limp mode. I'm not to the point of buying a good aftermarket torque converter so I thought about buying a line pressure booster. I've had the H&S overdrive software for about 15,000 miles now also. I wondered which booster is better.... Sonnax or BD-Power and can I use one of these with the overdrive software?
Thanks
 

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there both going to be the same thing, just a resistor to fool and up line pressure, but like many have found out, the line pressure can only go so high because of mechanical parts in the tranny, the h&s ups the line pressure so stacking with it, shouldnt do anything, but there has been a few say they have noticed a difference and the overdrive software works better with the line booster stacked.
 

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Discussion Starter #3
there both going to be the same thing, just a resistor to fool and up line pressure, but like many have found out, the line pressure can only go so high because of mechanical parts in the tranny, the h&s ups the line pressure so stacking with it, shouldnt do anything, but there has been a few say they have noticed a difference and the overdrive software works better with the line booster stacked.
Thanks man...I think I'll go ahead and get one or the other as cheap as they are. The mechanic that worked on my truck at the dealer said that there is a valve on the pump in the trans that is restricted. He said he had heard of a kit for a larger valve to produce higher pressure? Is there any other cheap upgrades I can do to lengthen the life of the trans?
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If it's going into limp-in mode, what faults do you have? A slipping TCC will light the MIL but should not put you in limp mode.

I doubt a line pressure "booster" will do much for you. The main regulator valve will only go so high, no matter how much you try to "fool" it. And if the TCM detects slippage, it already cranks up the line pressure. So I think you need to deal with whatever fault codes you have first.

With 104K miles on it, replacing the main valve body assy with a new (anodized) one would probably be a good idea. This can eliminate a potential problem with SSV bore wear that causes P0871 faults and OD clutch distress.
 

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Discussion Starter #5
If it's going into limp-in mode, what faults do you have? A slipping TCC will light the MIL but should not put you in limp mode.

I doubt a line pressure "booster" will do much for you. The main regulator valve will only go so high, no matter how much you try to "fool" it. And if the TCM detects slippage, it already cranks up the line pressure. So I think you need to deal with whatever fault codes you have first.

With 104K miles on it, replacing the main valve body assy with a new (anodized) one would probably be a good idea. This can eliminate a potential problem with SSV bore wear that causes P0871 faults and OD clutch distress.
Thanks TE for chiming in... I know your the man to talk to about all this.

My trans got to around 200 degrees then code p0700 came up. It was the same code as last time when the dealer told me my tc was slipping therefore making the trans too hot. Does this make since?

Replacing the valve body assy.... Is this necessary if I decide to put a aftermarket tc in and is it something I can do myself?
Thanks!!
 

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200 degrees is nothing to worry about. I wouldn't get concerned unless you were running over 230°F sump temp, and even that isn't extreme. Cooler is better, but operating at 200°F will not result in rapid trans failure.

The P0700 is a flag (in the ECM) that tells you there is some other fault set in the TCM. Your scan tool (like most aftermarket ones) apparently only reads codes in the ECM. You need to have your dealer check the trans codes (in the TCM), then let me know what you've got.

Yes, a valve body swap is really simple and you can DIY no problem. But check the faults first - that will give us a clue as to what's going on.
 

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Discussion Starter #7
200 degrees is nothing to worry about. I wouldn't get concerned unless you were running over 230°F sump temp, and even that isn't extreme. Cooler is better, but operating at 200°F will not result in rapid trans failure.

The P0700 is a flag (in the ECM) that tells you there is some other fault set in the TCM. Your scan tool (like most aftermarket ones) apparently only reads codes in the ECM. You need to have your dealer check the trans codes (in the TCM), then let me know what you've got.

Yes, a valve body swap is really simple and you can DIY no problem. But check the faults first - that will give us a clue as to what's going on.
Around 180 degrees my trans goes into limp mode... Where it only runs in 1st and 4th. So if my trans is safe up to around 230 degrees then why is it in limp? And how do others run that high of temp without throwing a code? It stays in the 150s whith the black Maxx on stock and me manual shifting.

I'll stop by the dealer asap and let you know what their scan tool says!
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1st and 4th gear limp-in is what we call "logical limp-in" and is typically in response to internal slippage within the trans (not the TCC). This is not related to trans temperature per se, but apparently when your trans gets above 180° sump it leaks enough, to slip enough, to blow a gear ratio error fault.

You should be able to run 250-260° sump temp without causing any slippage (although you wouldn't want to run that hot for extended periods). You have an internal problem, either a cut piston seal, or a burned clutch, etc that is giving you slippage. This could be related to a worn SSV bore in the valve body (it can leak pressure out of the OD clutch passage, resulting in OD clutch slippage).

Let me know what codes the dealer finds. Do you notice any slippage when it's in limp-in? If not, maybe you haven't damaged anything too badly yet, and if you're lucky maybe a simple valve body swap will fix you up. But let me know what they say....
 

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Discussion Starter #9
1st and 4th gear limp-in is what we call "logical limp-in" and is typically in response to internal slippage within the trans (not the TCC). This is not related to trans temperature per se, but apparently when your trans gets above 180° sump it leaks enough, to slip enough, to blow a gear ratio
Let me know what codes the dealer finds. Do you notice any slippage when it's in limp-in? If not, maybe you haven't damaged anything too badly yet, and if you're lucky maybe a simple valve body swap will fix you up. But let me know what they say....
when I took the truck in last time they hooked up their tool to the obd2 port and drive the truck. They told me the tq was slipping and making the trans hot. They also said that all the other components in the trans were in perfect condition. I don't knotice any slippage in limp that I can remember as I drove it today and never went into limp.

I will let you know!
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wore valve body accompanied with performance enhancers, and over 100k on the clicker is going to have smoked overdrives and possibly the beginning of the 4-C pack as well. "JMO"

But what ever the problem is you can be assured that TA will set you straight as he is full of knowledge and very valuable to this site.

Just sayin
 

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Discussion Starter #11
Well I finally got my truck to the dealer today. It went into limp at around 150 degrees right before I got there. They said a tcm code threw that was related to low pressure like the pump was bad or one of the two valves in the pump. I did not get the code that it threw so I don't have that info. I'm taking it in Monday so they can drive the truck with the scan tool hooked up then diagnose the problem.

TransEnginere... Is there any way that this was the original problem a few weeks ago and that my original torque converter was ok? Would the pump or valves cause the tc to slip and overheat?

Thank!
 

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A bad pump (excess side clearance, sticky regulator valve, etc.) that causes low line pressure could have caused your other problems. Again, based on your history, I don't think your TCC was slipping - I think you had internal slippage within the trans (apparently due to low line pressure when the trans got warm). That internal slippage would put you in logical limp-in, which inhibits TCC engagement, which would eventually cause trans overheat if you continued to drive it in that mode.

Low line pressure could be caused by something outside the pump (bad control system), although in your case, since it's temperature-related, I suspect an internal pump problem is most likely.
 

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Who is making an aftermarket valvebody for the 68, i have not been able to find them listed in any of the popular tranny sites.
 

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I don't know whether anyone is selling an aftermarket 68RFE valve body assy. My point is, if someone IS selling a "rebuilt" VB assy, I would be real careful about buying it, unless you knew that the SSV bore had been either (1) confirmed to still be within original print tolerance for a new part, (2) machined oversize with oversize SSV plugs installed, or (3) anodized (and within print specs).

The Mopar service VB assy for 68RFE (68033980AB) is a brand-new (not rebuilt) VB assy that is anodized and meets all print specs. That is your best bet if you need a replacement VB.
 

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Discussion Starter #15
Alright... Went to the dealer today. They drove my truck around with the star scan tool hooked up and said that everything was fine and that it must be my chip making it act up. I was pissed so I went and drove it around on stock and made it go into limp. So I come back they hooked up the tool and told me that it was a pressure related code and went into limp in 3rd and was trying to engage 3 gears at once. The mechanic said he's almost certain it's not the pump or 4-c pack. He thinks it's electrical related... Trans computer, or selinoid pack. When he replaced the tc he said all the insides looked good including the pump, etc. He wants to have the tool hooked up and driving it when it goes into limp so he can be certain it's not mechanical related. Therefore he is going to drive the truck home after work tmra and hope that it acts up.

What you think te??

Thanks!
 

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It would be nice if he'd tell you the actual fault code rather than saying "pressure related code." A low line pressure code (P0868) will NOT put you in limp-in (at least, not on a 2007 truck). For that matter, neither will ANY of the line pressure faults. So something else is going on (again, I'd bet it's internal slippage). Not that low line pressure couldn't be your problem - it just won't (by itself) put you in limp-in. Low line pressure will allow the trans to slip, and THAT will put you in limp-in. And by the way, limp-in is 4th gear (direct gear).

You really need to find out exactly what fault codes are set. It is possible to have a hardware failure in the TCM, but that usually presents itself as a solenoid circuit error, which is strictly an electrical (not a "pressure related") fault. So I don't think you have a TCM problem.

When your tech says "pressure related" does he related to overall line pressure, or related to the pressure in one particular clutch?

I'm gonna assume here that you are getting low line pressure. If your tech thinks that is control-related, there is a simple test: Connect a mechanical pressure gauge to the line pressure sensor port (your dealer has a special tool for doing this). Start the engine and let it idle in Park. Is the pressure LESS THAN the desired line pressure (DLP)? If not, warm it up until it starts going into limp, then check it again at idle. Odds are it will be less than DLP (this is not a problem by itself, since normally as soon as you open the throttle and engine speed comes up, line pressure jumps up to match DLP). Now, with the truck still idling in Park, disconnect the 23-way electrical harness from the transmission (driver's side). This disconnects the line pressure control (TCM) from the trans. Did the line pressure on the gauge jump up to a much higher value? If not, then the TCM and wiring are NOT causing a low-line-pressure problem. The pressure you're seeing is all the pump can make (mechanically). If the pressure DOES jump up, then the TCM was deliberately "turning down" the line pressure.

Note that if this test says the pump is bad, there is still a SLIM possibility that the solenoid (which controls line pressure) is failed mechanically, so it is "turning down" line pressure even when the TCM is not commanding it to do so. But that would be a VERY RARE failure (not likely). And if the solenoid is suspect, then at your mileage you should replace the entire valve body assy anyway (new VB will include a new solenoid).

Also note that this test must be properly understood. Normal "max pump pressure" in Park will be 160-170 psi. DLP (at idle in Park) may be 60-120 psi. If DLP is 60 psi, the TCM should be "cranking down" the line pressure (from 160 to 60 psi). So if you pull the 23-way and line pressure jumps to 160, that doesn't mean the TCM is bad. Under these conditions, that would be normal. But let's say DLP is 120 and actual line pressure is only 90 psi. The TCM SHOULD be commanding max line pressure (to try to crank it up to 120). So either the pump can't make more than 90, or the TCM isn't commanding the LP like it should. At that point, pulling the 23-way will show whether the pump is the cause (line pressure stays at 90), or the TCM is bad (pressure jumps up to 120 or more). Hope this makes sense.

The dealer can also read the duty cycle of the LP control solenoid (also known as the VFS) using the scan tool. At normal temps, the min duty cycle is about 5.1%. So if he sees a 5% duty cycle, that means the TCM is calling for "max" line pressure. At that point (no matter what DLP is), pulling the 23-way should result in little or no change in actual line pressure. On the other hand, if the duty cycle is, say, 15%, then pulling the 23-way should cause a change in LP (and would not mean the TCM was necessarily bad).

A few more notes: Pulling the 23-way will blow a bunch of trans faults (duh), so you'll need to clear them afterwards. You must have the engine running before you pull the 23-way, since once you disconnect it, you'll have no Neutral safety signal and the engine can't be started. As I said, "low" LP (below DLP) at idle is NOT a problem by itself. The true test is, does LP match DLP whenever the engine speed is around 1200 RPM or higher? If LP matches DLP above 1200 RPM, then your line pressure is OK.

Sorry for the long-winded response..... but then again I imagine you guys probably LIKE a long-winded response like this....
 

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CWB. I dont know what type of phone you have but if you run an android based phone buy and dowlaod thwe torque app and get a OBDII bluetooth adapter. I can read every code my truck says. ECM and TCM. My smarty will only tell me the P0700 but the torque app will tell me the exact code that triggers the 700 code. I know the P0729 and P0735 are 5 and 6 gear slip codes. I have had one imput related code. Thanks to my local dealer they finished off my trans when he was out "testing" the truck. So if your not in a rush to fix it, get the app and OBDII connector and see what your truck says.
 

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Discussion Starter #18
It would be nice if he'd tell you the actual fault code rather than saying "pressure related code." A low line pressure code (P0868) will NOT put you in limp-in (at least, not on a 2007 truck). For that matter, neither will ANY of the line pressure faults. So something else is going on (again, I'd bet it's internal slippage). Not that low line pressure couldn't be your problem - it just won't (by itself) put you in limp-in. Low line pressure will allow the trans to slip, and THAT will put you in limp-in. And by the way, limp-in is 4th gear (direct gear).

You really need to find out exactly what fault codes are set. It is possible to have a hardware failure in the TCM, but that usually presents itself as a solenoid circuit error, which is strictly an electrical (not a "pressure related") fault. So I don't think you have a TCM problem.

When your tech says "pressure related" does he related to overall line pressure, or related to the pressure in one particular clutch?

I'm gonna assume here that you are getting low line pressure. If your tech thinks that is control-related, there is a simple test: Connect a mechanical pressure gauge to the line pressure sensor port (your dealer has a special tool for doing this). Start the engine and let it idle in Park. Is the pressure LESS THAN the desired line pressure (DLP)? If not, warm it up until it starts going into limp, then check it again at idle. Odds are it will be less than DLP (this is not a problem by itself, since normally as soon as you open the throttle and engine speed comes up, line pressure jumps up to match DLP). Now, with the truck still idling in Park, disconnect the 23-way electrical harness from the transmission (driver's side). This disconnects the line pressure control (TCM) from the trans. Did the line pressure on the gauge jump up to a much higher value? If not, then the TCM and wiring are NOT causing a low-line-pressure problem. The pressure you're seeing is all the pump can make (mechanically). If the pressure DOES jump up, then the TCM was deliberately "turning down" the line pressure.

Note that if this test says the pump is bad, there is still a SLIM possibility that the solenoid (which controls line pressure) is failed mechanically, so it is "turning down" line pressure even when the TCM is not commanding it to do so. But that would be a VERY RARE failure (not likely). And if the solenoid is suspect, then at your mileage you should replace the entire valve body assy anyway (new VB will include a new solenoid).

Also note that this test must be properly understood. Normal "max pump pressure" in Park will be 160-170 psi. DLP (at idle in Park) may be 60-120 psi. If DLP is 60 psi, the TCM should be "cranking down" the line pressure (from 160 to 60 psi). So if you pull the 23-way and line pressure jumps to 160, that doesn't mean the TCM is bad. Under these conditions, that would be normal. But let's say DLP is 120 and actual line pressure is only 90 psi. The TCM SHOULD be commanding max line pressure (to try to crank it up to 120). So either the pump can't make more than 90, or the TCM isn't commanding the LP like it should. At that point, pulling the 23-way will show whether the pump is the cause (line pressure stays at 90), or the TCM is bad (pressure jumps up to 120 or more). Hope this makes sense.

The dealer can also read the duty cycle of the LP control solenoid (also known as the VFS) using the scan tool. At normal temps, the min duty cycle is about 5.1%. So if he sees a 5% duty cycle, that means the TCM is calling for "max" line pressure. At that point (no matter what DLP is), pulling the 23-way should result in little or no change in actual line pressure. On the other hand, if the duty cycle is, say, 15%, then pulling the 23-way should cause a change in LP (and would not mean the TCM was necessarily bad).

A few more notes: Pulling the 23-way will blow a bunch of trans faults (duh), so you'll need to clear them afterwards. You must have the engine running before you pull the 23-way, since once you disconnect it, you'll have no Neutral safety signal and the engine can't be started. As I said, "low" LP (below DLP) at idle is NOT a problem by itself. The true test is, does LP match DLP whenever the engine speed is around 1200 RPM or higher? If LP matches DLP above 1200 RPM, then your line pressure is OK.

Sorry for the long-winded response..... but then again I imagine you guys probably LIKE a long-winded response like this....
Wow very informative post. Thank you! I want to show the dealers mechanic this info but have not had the time to.

They did figure out that my tranny problem was the selinoid pack? They made it sound pretty conviencing so i had them go ahead and replace it. They did tell me that my tranny will not hold what the chip is putting out and to call suncost lol
 

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So, if they "figured out" that the solenoid was the problem, and they replaced it, then your truck is running fine now, and you have no more trans problems, right?
 

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Discussion Starter #20
So, if they "figured out" that the solenoid was the problem, and they replaced it, then your truck is running fine now, and you have no more trans problems, right?
Well... they drove it and said it was fine. I drove it about 2 miles home and it seemed to be fine but i have not had the opportunity to drive it long enough to tell or to pull anything. Ill know after today hopefully!

TE what do you think is a good upgrade to do to the trans to keep it from being the weak link? I know Suncoast has some different options to help without blowing a full 10 grand on a built tranny.
 
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