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Not sure if the 4.10's have anything to do with it but seems as though that, TRYING to maintain 40mph(city speed) seems that the trans is stuck between 3rd/4th. Shifts smooth but maintaining speed itll act up...sometimes. Fluid is FINALLY correct(stupid story).
Has anyone done business with this company
http://www.monstertransmission.com/Heavy-Duty_c_3928.html
Morn'n mark....maintaining the city speed, the trans cant decide if it wants to shift into 4th or stay inb3rd. Rpms verfy it. Its why i mention the gear ratio. Also, its not ALL the time it does it but majority. Im green when it comes to autos, boss
The Coast Clutch (Overdrive) Engage/Disengage at approximately 42 MPH (Load dependent). You're right at that "Grey Area" where it may shift back and forth. Especially utilizing Cruise Control. Is this the only symptom? Otherwise, suggest you alter your speed up or down slightly to avoid the I/O of the Coast Clutch.
You nailed it pirch... Only on city roads and thats the posted speed. Wonder if, keeping her out of OD would help? Been looking into trans rebuilds/remans along with different TQ's because im goin nutz. Then i read about "low stall speed" convertors. Now, i really have a pretzel in my head..
The Coast Clutch (Overdrive) Engage/Disengage at approximately 42 MPH (Load dependent).
The coast clutch is NEVER engaged when the gearshift is the D position and the OD OFF light is not on. And the coast clutch can NEVER be engaged in overdrive. That will cause a tie up which causes the rear wheels to stop turning RIGHT NOW.
You may be thinking of the torque converter clutch. That engages about that speed and is load dependent. It is also not overdrive. Overdrive is fourth gear and is created by engaging the overdrive clutch.
If it is only doing this at one particular speed it is most likely the programming that is causing this. Installing a new transmission won't fix this. New software is the only way to fix it.
Morn'n mark....maintaining the city speed, the trans cant decide if it wants to shift into 4th or stay inb3rd. Rpms verfy it. Its why i mention the gear ratio. Also, its not ALL the time it does it but majority. Im green when it comes to autos, boss
Originally Posted by Mark Kovalsky
If it is only doing this at one particular speed it is most likely the programming that is causing this. Installing a new transmission won't fix this. New software is the only way to fix it.
Food for thought, I had something similar happen. I had been running a 6-position chip for a couple of years and then developed a 2-3 shift "hunt" in a couple of tunes. I lived with it for a bit but it was happening around 25mph-ish which was driving me crazy. I didn't know if it was bad for the transmission but it definitely couldn't have been good. I finally called the tuner and described my issue. I sent them my chip (no shifting issues without the chip) and they burned updated files into all the positions for me and sent it back. Problem solved.
Thats a perfect phrase for what's happening.."hunt".
I'll try thr no OD on and see if that works. Not sure if ever a chip or program to the pcm since i just bought it end of dec. However, i did have a VSS installed and loaded up.
Thanks fellas, will update over weekend
I can say from my limited experience driving my truck, not towing, I can cruise as low as high 30's while in OD. That or maybe my Speedometer is registering a few MPH high.
I do have to reach the minimum 40-42MPH to shift into OD but then I can coast a bit down in the high 30's and maintain just fine without speeding to much on 35 limit roads. Having said that, this is on flat roads.
If I want to accelerate without down shifting, I must manage the pedal just enough to accelerate without pressing to hard to down shift. I can imagine having a hard time doing the same thing under 40MPH on an incline.
When testing the truck prior to buying it, i dont remember it doing that. Thats why im wondering if the 4.10 gearing is playing a role in this. Does the pcm do anything that involves said rpm/speedo? Gunna hit the road here ina few. Will post up later
The difference between 4.10 and 3.73 is only about 10%. So any symptom you have with your gears would happen at a 10% higher speed if you had the default gears.
So I think it is unlikely to be your gears per se. Three questions...
Did you change the gears? Asking since you mention them.
Also, do you have tunes on the truck?
Finally, do you see the problem if you lock out overdrive?
The coast clutch is NEVER engaged when the gearshift is the D position and the OD OFF light is not on. And the coast clutch can NEVER be engaged in overdrive. That will cause a tie up which causes the rear wheels to stop turning RIGHT NOW..
So, the Torque Converter is controlled by the OD? Not the Coast Clutch? Like SGT Shultz, ..... I know nothing..... where A/T's are concerned. I really wish I had entered that field. If, for no other reason than the Knowledge that could be obtained.
The torque converter is controlled by the computer, which commands the torque converter clutch solenoid to lock or unlock the torque converter clutch. Neither the coast clutch nor the overdrive is related to the torque converter clutch. All three are separate items. The torque converter can lock or unlock if the coast clutch is on or off, or if the transmission is in overdrive or not in overdrive.
Finally was able to drive her yesterday(wife calls it our sunday truck). With OD off, there was no "hunting" going on. But strange though, doinh 35-40 then approaching a stoplight, to me, the truck felt like i was dragging an anchor up until 10mph ish, then "thru the pedal" you can feel the trans "release" and coast/brake accordingly..is this the tq still locked up until a desired speed? It goes thru the gears just fine. No hard shifting..etc with OD off but you definitely know that theres that 1 more gear left, IF i turned OD on....