Truck stalls out when put in reverse. Parts replaced.....
#21
12-16-2018, 11:25 AM
Legend
I'm not up on Dodges so I may be off base here, but...
If the IAC were the problem, I would think it would be a problem regardless of the transmission setting. Anything else forward of the transmission would be the same, it wouldn't affect just one specific gear. Anything behind the transmission would also affect all gears. That the truck doesn't act up when put into reverse when the rear wheels are off the ground points to a loss of pressure here as well, since there is no resistance in the transmission caused by the rear wheels not moving. When the rear wheels are on the ground, there is going to be more resistance inside the transmission from trying to turn the wheels but not being able to.
What is odd here is that it is killing the engine, which implies that the torque converter is locking when the trans is shifted to reverse. The torque converter always spins the same direction regardless of what gear the transmission is in. Any problems in the trans should not be transmitted to the engine, because the torque converter's whole purpose is to allow the engine to spin freely while the transmission is not moving. It's almost like there is a short in the transmission which causes the TC to lock up when it's shifted into reverse. If this is the case, taking the rear end off the ground would not affect it because the wheels are being allowed to spin right off. But, if the rear wheels are on the ground and the TC locks, then it's like stopping a manual trans car while it's in gear without pushing in the clutch. It is enough to shut down the engine. I'd wonder if you repeated the rear wheels off the ground test again, if you'd be able to kill the engine by shifting to reverse then holding the brakes on hard. As the rear brakes are weaker than the front, you wouldn't necessarily have had enough pressure on the rear wheels to keep them from spinning when you put the brake on enough to shift. On magnethead's thinking that the input drive is seizing, the TC does drive the trans pump that should be on the input shaft. I wouldn't think that the pump seizing would be enough to keep the TC from spinning, but I guess it's possible.
Hope some of this helps.
If the IAC were the problem, I would think it would be a problem regardless of the transmission setting. Anything else forward of the transmission would be the same, it wouldn't affect just one specific gear. Anything behind the transmission would also affect all gears. That the truck doesn't act up when put into reverse when the rear wheels are off the ground points to a loss of pressure here as well, since there is no resistance in the transmission caused by the rear wheels not moving. When the rear wheels are on the ground, there is going to be more resistance inside the transmission from trying to turn the wheels but not being able to.
What is odd here is that it is killing the engine, which implies that the torque converter is locking when the trans is shifted to reverse. The torque converter always spins the same direction regardless of what gear the transmission is in. Any problems in the trans should not be transmitted to the engine, because the torque converter's whole purpose is to allow the engine to spin freely while the transmission is not moving. It's almost like there is a short in the transmission which causes the TC to lock up when it's shifted into reverse. If this is the case, taking the rear end off the ground would not affect it because the wheels are being allowed to spin right off. But, if the rear wheels are on the ground and the TC locks, then it's like stopping a manual trans car while it's in gear without pushing in the clutch. It is enough to shut down the engine. I'd wonder if you repeated the rear wheels off the ground test again, if you'd be able to kill the engine by shifting to reverse then holding the brakes on hard. As the rear brakes are weaker than the front, you wouldn't necessarily have had enough pressure on the rear wheels to keep them from spinning when you put the brake on enough to shift. On magnethead's thinking that the input drive is seizing, the TC does drive the trans pump that should be on the input shaft. I wouldn't think that the pump seizing would be enough to keep the TC from spinning, but I guess it's possible.
Hope some of this helps.
#22
12-20-2018, 12:05 PM
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Great insight!
I did try holding the brakes method when the rear end was off the ground and when I held them and went into reverse I could cause the truck to stall. When I had the rear off the ground I would shift from park to reverse and I'd have to time the brake pedal release quickly as to try and not bog the motor too much. A few times I held the brake longer and it would cause a drop in the rpms. If I pulled my foot off the brake as quickly as I could it was pretty much seamless.
I did try holding the brakes method when the rear end was off the ground and when I held them and went into reverse I could cause the truck to stall. When I had the rear off the ground I would shift from park to reverse and I'd have to time the brake pedal release quickly as to try and not bog the motor too much. A few times I held the brake longer and it would cause a drop in the rpms. If I pulled my foot off the brake as quickly as I could it was pretty much seamless.
#23
12-20-2018, 12:25 PM
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I just went back and revised this thread for like the 10th time. I posted the link in one of my replies but this seems IDENTICAL to my situation. Read again... https://www.jeepforum.com/forum/f13/...68/index3.html
#24
12-20-2018, 06:31 PM
#25
12-20-2018, 09:16 PM
Legend
I think this new thought train of a torque converter issue is in the correct direction. Luckily, that is a fairly easy fix. But I would also suggest flushing the trans out at the same time/getting it checked out in case there has been a hard fault and ther eis metal floating around.
Most likely would be a failed sprague or seized bearing.
Most likely would be a failed sprague or seized bearing.
#26
12-21-2018, 01:52 PM
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I think i'm going to pull the torque converter and slap in a new one. I bought this truck to give to my brother and more less just be transportation that he's needed. I may risk not going through the trans when it's out as the investment side as well as it drives perfectly except in reverse. Maybe i'll get lucky??
#28
12-25-2018, 08:28 PM
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#30
12-25-2018, 08:52 PM
Before going through the trouble of replacing the TC, inspect the trans wiring harness for damage. The exhaust passes pretty close to the trans. It would suck to replace it just to find it was a shorted wire outside the trans. Someone else would need to chime in on whether or not it's possible for a wiring short to exist inside the trans that would affect the TC..