98 SC1 Tranny shift issue

I've got a 98 SC1 auto tranny which is "knocking", "banging" when I shift in the high RPM's. I normally tend to drive with a heavy foot and this has never been an issue before but now when I accelerate it shakes the car. But if I depress the accelerator gently it doesn't kick.

Any advice?

Possibly bad motor mounts...especially the upper engine mount. Check it and replace it if needed.

you could have bad mounts. the top axis mount is a normal suspect and you can usually just look at it without taking it off to see cracks in the rubber. the torque struts (dog bones) usually are a bit harder to tell. you normally have to take them off to inspect. usually the round small end is damaged. the rubber will be cut and sticking out. all the mounts are easy to replace and can cost about $100-$120 for the tam and tsms. normally dont have to worry about the lower tranny mount which does crack over time, but is from other mounts being dead. once other ones are good, it can normally stay torn and cause no further problems.

now too, you may have a problem with the valve body or torque converter. have you had the tranny flushed and filter replaced? trust me, it is so simple. if you can change the oil, you can change the tranny fluid. its exactly the same on s-series. you have a filter on the front and a drain plug on the flexplate side of tranny. but just draining the fluid doesnt get it all out. you will still have fluid in the heat exchanger and torque converter. you can buy additional tranny fluid and drain the tranny. fill it back up (not all the way) start engine, put in drive for a couple minutes. put in park, shut it off, and drain again. repeat that till fluid is pure red, like how it went in. now when its flushed, replace the filter.

I will check the Mounts tonight and see if that might be the issue. Here is another symptom along with what I have experienced thus far.

Now when the car is shifting up, it will occasionally rev the RPM's as it shifts. Any ideas?

I will check the Mounts tonight and see if that might be the issue. Here is another symptom along with what I have experienced thus far.

Now when the car is shifting up, it will occasionally rev the RPM's as it shifts. Any ideas?

Replace the ECTS.

Change your fluid and filter. Should be changed every 20k miles

Looks like the mount is shot... I was able to slide a ballpoint pen under the mount without any resistance. I am planning on replacing it tonight. I will let you know how the fix works.

Mount replaced, looks like a bad starter too, but knocking is still an issue. Drove smooth for approx 5 mins then the knock and banging came back. Tranny fluid looks red, little dark but I will try and replacing it. Lets hope its nothing major.

Ok, After a weekend of car repairs here is what we have.

New starter, new top motor mount and fresh tranny flush with new filter and 1 24oz bottle of Lucas No slip.

Problem still there, what is happening?

Replace the ECTS.



Does it slam into reverse?

It does have a slight hesitation/kick... Wolfman's Cure? Can I do that without replacing the new fluids?

It does have a slight hesitation/kick... Wolfman's Cure? Can I do that without replacing the new fluids?

Unfortunately no :( New fluid is vital to the procedure being successful. I actually use fluid from walmart bc i replace it often. You should be ok with the filter though.

Ok, ran Wolfman and took it for a test drive. Still slips/kicks a little bit from 1 to 2 but the rest of the gears seem to be better. I will really know the results in the morning once I make the daily 30 mile commute.

Thats good! May want to do the procedure one more time and see if it helps a little more.

The next step if it is not better would be to tighten the the input shaft nut, as the constant banging in reverse starts to loosen it. This then usually gives people problems in second gear. Sometimes as bad as they have no more second gear because the clutch packs are to loose. A new input shaft nut is needed from the dealer, about 6 bucks IIRC. I can tell you how to do it if you think its needed.

Morning drive wasn't too bad. Reverse slam cure seemed to work well. Still kicks about 1/2 the time at 10-20% throttle, so I will run the cure again tonight.

I would love to know how to replace the Input Shaft Nut if you can teach me. My only concern in where it's located and dropping the tranny.

Thanks so far to everyone for their help.

Well I guess things just get better. Ran the Wolfman Cure again last night for the 2nd time drove it and still an issue. Kind of lucked out this morning with a SES light and will pull the code tonight to see the issue. I'm thinking that a new Input Shaft Nut and Line Pressure Solinoid will solve the issues, any ideas?

Ok here is the code from the SES when I ran the ODB II check.

0741 - Came back as a "Torque Converter Clutch Circuit Performance or Stuck Off"

I hate to ask, but what the h@#$ mean?

Ok, went to the local Autopart store, purchased the new $10 ECTS, installed it and made my morning commute; minor, minor kick on 2nd but smooth the rest of the gears. How the H3ll does that happen?! I'll keep an eye on the rest of the drive but I don't get how the ECTS is tied into the tranny.

The ECTS is VITAL to many sub systems of the car including air/fuel ratios, idle control, timing, fan operation, emissions, and even tranny operations such as shift points and Torque Converter lock up points.

I would not remove the PCM B fuse in the under hood junction box...this will reset the PCM and revert it to its stock shifting tables. From here it will relearn your driving habbits and may improve your tranny performance.

Make sure the connector to the ECTS is clean and corrosion free also.

So here we are almost 1 year later. Car just threw a P0773 "Shift Solenoid E Electrical" at me. Is it time for a new Valve Body? Or what's the point now?

So here we are almost 1 year later. Car just threw a P0773 "Shift Solenoid E Electrical" at me. Is it time for a new Valve Body? Or what's the point now?

How many miles have you put on the car?

More then likely this is the line pressure solenoid. Its easy to replace, not sure on price though. If you want to replace the whole valve body, then there is a guy Special Forces who every one buys from. His rep is outstanding.

Also make sure your electrical system is working well. 14V at idle is what you should see at the battery. These cars are very sensitive to voltage diffferences.