Any car people here today who can asnwer a transmission flush question

[farmkid]

Re: Any car people here today who can asnwer a transmission flush ques

Hi farmkid, thanks for explaining this. It makes a lot of sense. ANd thanks for asking your brother. Please let me know what he thinks. MY car failed inspection yesterday due to two bad tires (back ones) so this is like the perfect storm lol! I'll be replacing those tires next week. take care, and thanks again.

I finally got to explain your situation to my brother and here's what he said. He agreed with me that flushing the transmission shouldn't cause any more problems. The only time it does is in cases where it's in really bad shape and just about to die anyway and all the sludge is sealing off all the cracks and leaks. In those cases, a flush will get rid of that sludge and the transmission will fail soon thereafter. However, the key here is that the transmission was just about dead anyway--the flush only hastened the inevitable a little. He also explained a little more about how the flush machines work. It's hooked in series between the cooler and the transmission. There is a bladder between two compartments inside the machine--one is filled with fresh fluid. As the transmission pumps fluid into the empty compartment, the pressure pushes fluid out of the other compartment and back into the transmission. As I said earlier, as far as the transmission is concerned there's nothing going on except that new fluid is coming back from the cooler instead of old. It's not stirring anything up or washing anything out. If the fluid smells burnt this may be a good idea. If that's true, you also have to think about why the fluid may have gone bad. It could be caused by driving aggressively in a hilly area, especially if you were towing something. Otherwise, your transmission may have some other problem that is preventing the torque converter from locking up. If you haven't done any driving that might stress the transmission, it might be worth having that looked at.

As for the hesitation, it's likely one of three things. If the engine sputters and then takes off it's probably an ignition issue. If the engine winds up and then the car begins to accelerate, then it's probably clutches in the transmission slipping and may be caused by the bad fluid. If there's a short delay of a half second or so and then the car jerks forward, it's probably the motor mount bushings. As for which is more important, it depends on how bad the bushings are. As I said earlier, running with bad tranny fluid will wear the transmission faster and shorten its life. If the bushings are only worn a bit, they will probably be okay for a while, but if they're really bad there could be a more catastrophic failure. The most likely problem is that they could allow the engine to drop some, causing a misalignment of the axle shafts and possibly causing one of them to break.

 

[indranee]

Re: Any car people here today who can asnwer a transmission flush ques

Happy 4th of July everyone!!!

Hi farmkid, thanks for explaining this. It makes a lot of sense. ANd thanks for asking your brother. Please let me know what he thinks. MY car failed inspection yesterday due to two bad tires (back ones) so this is like the perfect storm lol! I'll be replacing those tires next week. take care, and thanks again.

I finally got to explain your situation to my brother and here's what he said. He agreed with me that flushing the transmission shouldn't cause any more problems. The only time it does is in cases where it's in really bad shape and just about to die anyway and all the sludge is sealing off all the cracks and leaks. In those cases, a flush will get rid of that sludge and the transmission will fail soon thereafter. However, the key here is that the transmission was just about dead anyway--the flush only hastened the inevitable a little. He also explained a little more about how the flush machines work. It's hooked in series between the cooler and the transmission. There is a bladder between two compartments inside the machine--one is filled with fresh fluid. As the transmission pumps fluid into the empty compartment, the pressure pushes fluid out of the other compartment and back into the transmission. As I said earlier, as far as the transmission is concerned there's nothing going on except that new fluid is coming back from the cooler instead of old. It's not stirring anything up or washing anything out. If the fluid smells burnt this may be a good idea. If that's true, you also have to think about why the fluid may have gone bad. It could be caused by driving aggressively in a hilly area, especially if you were towing something. Otherwise, your transmission may have some other problem that is preventing the torque converter from locking up. If you haven't done any driving that might stress the transmission, it might be worth having that looked at.

As for the hesitation, it's likely one of three things. If the engine sputters and then takes off it's probably an ignition issue. If the engine winds up and then the car begins to accelerate, then it's probably clutches in the transmission slipping and may be caused by the bad fluid. If there's a short delay of a half second or so and then the car jerks forward, it's probably the motor mount bushings. As for which is more important, it depends on how bad the bushings are. As I said earlier, running with bad tranny fluid will wear the transmission faster and shorten its life. If the bushings are only worn a bit, they will probably be okay for a while, but if they're really bad there could be a more catastrophic failure. The most likely problem is that they could allow the engine to drop some, causing a misalignment of the axle shafts and possibly causing one of them to break.

Hi farmkid, thanks for asking your bro. I really appreciate it. The tranny fluid looks reddish-brown to me, not darker but the mechanic mentioned a flush so I may get that done after the tires. Thanks also for the detailed explanation.

As for the three options, it's this one:

If there's a short delay of a half second or so and then the car jerks forward, it's probably the motor mount bushings.

When I pull out of a stop sign or a red light, there's this slight hesitation from 1st gear to the 2nd (my car's an automatic) and then it runs fine. It doesn't happen all the time,; say, about 30% of the time. I do feel quite a bit of jerking around when I go over potholes and speedbumps (I try to avoid them but alas, not much luck in DC and MD). The problem is that the hesitation's been happening for a while and I'm nervous. However, I checked through all my receipts and it seems two of the mount bushings *were* replaced last year by a mechanic friend I knew back when I used to live in Virginia. I'm going to go back to him and ask him what the deal is there. They shouldn't go bad so fast, right?

 

[indranee]

Re: Any car people here today who can asnwer a transmission flush ques

I'm with farmkid on this. The big difference is that when you simply drop the pan to change the transmission fluid you cannot drain the fluid in the torque converter. Flushing the fluid forces new fluid into the entire transmission, thereby forcing all of the old fluid out.

One thing you have failed to mention is whether your car is a stick or an automatic. With an automatic, your fluid should be a reddish brown when fresh and not smell burnt. To check, take the car out and run it for 45 minutes or so, making sure the transmission goes through all the gears. Then check the fluid when the engine is still hot.

Something else that you should know...when you have the transmission flushed, you should also have them drop the pan and change the filter. This will cost a bit more, but will extend the life of your transmission.

As far as your motor mounts go, there is an easy test, but it requires another individual. Have that individual sit in the car with the motor running. With the hood up, have this individual shift from Park to reverse and drive while holding the brake pedal down as far as they can. While they do this, you watch the top of the motor. If the motor shifts more than an inch to either side, your mounts need to be replaced.

Regarding your current driveability issues, when was the last time you had your fuel filter replaced? What you describe sounds to me more like a partially clogged fuel filter than it does issues with either the transmission or the motor mounts.

Hi Captain Ice, nice to hear from you

Thanks for the advice. My car's an automatic. The tranny fluid looks reddish brown to me. I'm going to check for the burnt smell soon. One question: should the engine be running when I do that?

As for the motor mount testing... I'm going to get my mechanic to maybe do that mainly because I got that earlier diagnosis from Firestone and they're bastards (no offense to any individual FS employee or anyone on here affiliated with them but they've burned me many times before).

 

[farmkid]

Re: Any car people here today who can asnwer a transmission flush ques

If there's a short delay of a half second or so and then the car jerks forward, it's probably the motor mount bushings.

When I pull out of a stop sign or a red light, there's this slight hesitation from 1st gear to the 2nd (my car's an automatic) and then it runs fine. It doesn't happen all the time,; say, about 30% of the time. I do feel quite a bit of jerking around when I go over potholes and speedbumps (I try to avoid them but alas, not much luck in DC and MD). The problem is that the hesitation's been happening for a while and I'm nervous. However, I checked through all my receipts and it seems two of the mount bushings *were* replaced last year by a mechanic friend I knew back when I used to live in Virginia. I'm going to go back to him and ask him what the deal is there. They shouldn't go bad so fast, right?

If the hesitation is when it's shifting, then it's not caused by the motor mounts. That would only be when accelerating from a stop. That hesitation is caused by the engine itself rotating and taking up the slack that comes from worn mounts. The jerk happens because the engine is now wound up and everything in the drive train is moving when the slack is finally gone and the car jerks forward. It's similar to what happens if you're water skiing and the boat takes off before the rope is tight.

If your car hesitates when shifting, that slack would be gone already by that time, so I doubt the worn bushings are the cause. A hesitation during a shift, however, does sound like a transmission issue to me--either bad oil, or something else may be going wrong with the transmission.

 

[indranee]

Re: Any car people here today who can asnwer a transmission flush ques

Yeah, I think it may be a transmission thing. I'll be taking it back to the shop this week. Will update as to what I find out. Mucho thanks to everyone who helped. I really appreciate it.