Piston Slap: Crystal Ballin' With Yo Tranny! (Part II)

Aaron writes:

Hey Sajeev,

Huge fan of TTAC and the piston slap articles. My problem is that I noticed my car(2007 honda civic)would shudder, under light throttle and low rpms especially when going up a slight slope. This usually happens at 30km/hr or 40km/hr. I took it to the honda dealer(4 months ago) and he said the torque converter(tc) needs to be replaced(300 for tc plus 900 for labour and stuff).

My university got a bit busy and I took some time to think about it. The problem might be slightly worse now so I recently went back to the dealer to get more details about the cost and now they are saying the price of the tc has increased to 800 plus another 800 for labour. The guy suggested maybe just changing the transmission fluid(because it is starting to get dark) and driving the car until it fails and getting a new transmission for $3000 because the transmission will probably go out soon anyway.

I’m not sure what to do now. I’m considering going to a transmission shop and see if they can change the tc, but I’m worried about going to a random mechanic. I know a small time mechanic whom I go to for small stuff but I’m not sure if his shop is capable of swapping the tc(is it that complicated?). I have also looked online and found other people saying that if the torque converter is failing, the transmission is probably going to go soon. Some other people have said that if the torque converter fails, it could take out the rest of the transmission which might have been working fine otherwise. I then found another group of people saying that I should just drive the car without changing the transmission fluid because even changing the fluid could cause the transmission to fail sooner.

I just want to know which of these are actually true and what should my next course of action be. If the torque converter can be changed for a reasonable price and my transmission keeps working, I would like to do that. Or maybe I should see if I can get the entire transmission rebuilt or replaced.

Thank you,

P.S: Not sure if this matters, but the car once overheated severely (about 3 years ago) and about half the engine had to be replaced under warranty. The engine has been running smoothly since then and the only other problem is that recently(2 months ago) my engine starter and battery had to be replaced. The battery connectors also look pretty bad so I’m going to replace that soon. Hmmm maybe I should just sell my car.

Sajeev answers:

Oh great, another mystery box transaxle/ crystal ballin’ yo tranny problem: one day the B&B will string me up for these blind guesses.

That said, on a more serious note, how many miles are on the Civic?

Aaron responds:

Hey Sajeev,

Thanks for the quick reply. It has 156,000 km(96,000 miles). Admittedly, the car has been driven pretty hard. I just did a quick stall speed test(mashing the brake and hitting the throttle) and the revs went up to 2,500rpm in both drive and reverse. That seems pretty normal. I drove around trying to recreate the problem(Light throttle and flat roads or slight inclines).

It happens at:

• 15 or 20km/h (9 or 12mph)
• 30ish km/h (18mph)
• 40ish km/h (25mph)
• And at 55ish km/h (34.18mph), the shuddering is only minor at this speed

There is also a sound when this happens, it sounds like metal spinning against metal in a liquid. However, this sound can only be heard if the shuddering is not too violent. If it is violent, it just sounds like the car kind of wants to stall. I checked the transmission fluid and it looks pretty brown and has a slight burning smell. If the car is accelerating faster( atleast above 2000rpm), it feels like there is no problem. Also no problem when slowing down.

Sajeev concludes:

Great assessment! At this age (under 100k miles) odds are new and correct fluid will solve it: flush the old fluid out of the converter and also drop the pan to change the filter. Which might be asking a lot for many shops, but I’d want all the old ATF out of the system. So will this cure the problem? Will thoroughly removing varnished ATF cause even more problems than a shudder?

Maybe on both counts. Or maybe one and not the other. See how much fun this is for me?

My best guess: do as the dealer said, change the fluid. If it fails, get a rebuilt transaxle from a Honda savvy shop. Because opening up a transaxle for anything and not doing a rebuild is likely a waste of time, labor and money.

It’s usually best to prolong that moment with anything…including a fluid change. Even if the fluid change actually shortens the tranny’s lifespan. So much fun!

[Image: Shutterstock user Scharfsinn]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.