Trans line check valve symptom???
#32
10-23-2010, 11:20 PM
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Root problem in my case was a bad MAP reading thus requiring a new sensor from the dealer this morning. All i good in the hood now.
Thanks for al the help and information on those items.
Last question: if and when the time comes: does any one have a supplier for rebulit trannies? I would like to have one on hand when this one craps out.
Thanks,
CM
Thanks for al the help and information on those items.
Last question: if and when the time comes: does any one have a supplier for rebulit trannies? I would like to have one on hand when this one craps out.
Thanks,
CM
#33
10-24-2010, 08:39 PM
So you changed the map sensor and that fixed it? So it wasn't a trans shifting issue, right? In other words, the map sensor doesn't have anything to do with trans shifting, does it? Sorry, just trying to see what the new map sensor fixed. Assuming it fixed an engine performance issue (bog).
How it works, is, the MAP is tied to the PCM and provides data to the PCM and, since everything in the RAM almost is electronically controlled, the PCM and all sensors are very important for the vehicle to run properly.
The bogging was not an engine issue. The MAP reading was out of whack, thus throwing the VAC level and, my A/F and, my timing way out of whack. I'm surprised that the engine actually ran at all and got as good mileage as it did under the circumstances.
Now, the tranny has some solenoids for the O/D unit and, since the MAP reading was way out, the PCM was not switching the solenoids at the tranny level thus, I was stuck in 4 HI going up hills, under load thus, leading to bogging and detonation.
I replaced the MAP in the dealer lot and, immediately, it ran totally different and felt like new along with down shifting up hill as it used to.
Always, check all sensors because, if one is out, it affects a lot of other systems.
CM
Last edited by cmckenna; 10-24-2010 at 08:59 PM.
#35
10-24-2010, 11:23 PM
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The MAP sensor in part, controls the transmission down shifting - YES. The MAP was to blame for my tranny NOT down shifting.
How it works, is, the MAP is tied to the PCM and provides data to the PCM and, since everything in the RAM almost is electronically controlled, the PCM and all sensors are very important for the vehicle to run properly.
The bogging was not an engine issue. The MAP reading was out of whack, thus throwing the VAC level and, my A/F and, my timing way out of whack. I'm surprised that the engine actually ran at all and got as good mileage as it did under the circumstances.
Now, the tranny has some solenoids for the O/D unit and, since the MAP reading was way out, the PCM was not switching the solenoids at the tranny level thus, I was stuck in 4 HI going up hills, under load thus, leading to bogging and detonation.
I replaced the MAP in the dealer lot and, immediately, it ran totally different and felt like new along with down shifting up hill as it used to.
Always, check all sensors because, if one is out, it affects a lot of other systems.
CM
How it works, is, the MAP is tied to the PCM and provides data to the PCM and, since everything in the RAM almost is electronically controlled, the PCM and all sensors are very important for the vehicle to run properly.
The bogging was not an engine issue. The MAP reading was out of whack, thus throwing the VAC level and, my A/F and, my timing way out of whack. I'm surprised that the engine actually ran at all and got as good mileage as it did under the circumstances.
Now, the tranny has some solenoids for the O/D unit and, since the MAP reading was way out, the PCM was not switching the solenoids at the tranny level thus, I was stuck in 4 HI going up hills, under load thus, leading to bogging and detonation.
I replaced the MAP in the dealer lot and, immediately, it ran totally different and felt like new along with down shifting up hill as it used to.
Always, check all sensors because, if one is out, it affects a lot of other systems.
CM
#36
10-25-2010, 12:00 PM
I may have the same thing goin on. My truck likes to stay in overdrive. It takes what seems like an excessive amount of gas pedal to get it to downshift. I did change the tps, which helped some. Say if I slow down to 45-50 mph, the tc will stay locked unless I push the pedal about half way to the floor. Is that similar to what your truck would do or is that normal? Has been doing it a long time, so I just assumed these trannies liked to stay in od. No pinging or anything, just a normal lack of power since rpm,s are so low.
Is that similar to what your truck would do
Now, in your case, you may ask someone on here if the TV cable can be ever-so-slightly adjusted to achieve quicker down-shifting points. I don't know this system but, from my reading, it looks as though, that cable can be adjusted to alter the shift points. However, the manual / spec states that it must line up on center to prevent damage to the trans.
CM
Last edited by cmckenna; 10-25-2010 at 12:13 PM.
#37
10-25-2010, 01:04 PM
Grand Champion
Another cause of kickdown problems could be the TPS, which bears looking into if the converter clutch (which is under PCM control) is hanging on too long. If the new TPS is an aftermarket part, it might be out of tolerance... testing is in order, as it makes no sense at all to change out a new component without knowing precisely why.
#39
10-25-2010, 10:54 PM
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Trans was rebuilt, the guy who rebuilt it said he put b and m shift kits in all the dodge truck transmissions he rebuilds. Was rebuilt before I read on here about the sure cure kit and transgo shift kit, but ya live ya learn. It shifts pretty firm now, I did move the tv cable a bit in the past, but I either noticed no difference or it would shift too hard, so I have it back to stock (clip lined up with the pin on tb lever). I also replaced my tps with one off another 98, and that did help some. Seems to kick down a tad earlier and hold 3rd gear a bit longer, which I like.
So lemme ask the main question to you all. My tc will not come out of lockup without downshifting. I've really never driven automatics for any length of time other than my dodge. I recently drove a z71 and my dad's f150. I noticed both trucks would come out of lockup if you mashed down on the gas slowly, then the rpms will go up, but they wouldn't necessarily downshift to 3rd if you didn't continue mashing the gas. Mine will not do that. If you start mashing the gas slowly, it'll wait till about half throttle,come out of lockup, and immediately downshift to 3rd. Is that normal for our trucks? I have the entire tb with all sensors from a scrap truck. Thought the sensors might come in handy. I suppose I could switch map sensors and see what happens. Mainly, I'd like to know if they're supposed to come out of lockup without going to 3rd for a small rpm jump and a little low speed passing power.
So lemme ask the main question to you all. My tc will not come out of lockup without downshifting. I've really never driven automatics for any length of time other than my dodge. I recently drove a z71 and my dad's f150. I noticed both trucks would come out of lockup if you mashed down on the gas slowly, then the rpms will go up, but they wouldn't necessarily downshift to 3rd if you didn't continue mashing the gas. Mine will not do that. If you start mashing the gas slowly, it'll wait till about half throttle,come out of lockup, and immediately downshift to 3rd. Is that normal for our trucks? I have the entire tb with all sensors from a scrap truck. Thought the sensors might come in handy. I suppose I could switch map sensors and see what happens. Mainly, I'd like to know if they're supposed to come out of lockup without going to 3rd for a small rpm jump and a little low speed passing power.
#40
10-26-2010, 04:18 PM
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So lemme ask the main question to you all. My tc will not come out of lockup without downshifting. I've really never driven automatics for any length of time other than my dodge. I recently drove a z71 and my dad's f150. I noticed both trucks would come out of lockup if you mashed down on the gas slowly, then the rpms will go up, but they wouldn't necessarily downshift to 3rd if you didn't continue mashing the gas. Mine will not do that. If you start mashing the gas slowly, it'll wait till about half throttle,come out of lockup, and immediately downshift to 3rd. Is that normal for our trucks? I have the entire tb with all sensors from a scrap truck. Thought the sensors might come in handy. I suppose I could switch map sensors and see what happens. Mainly, I'd like to know if they're supposed to come out of lockup without going to 3rd for a small rpm jump and a little low speed passing power.