Hi guys,
let me start with the basics, 98 TR A4 no mods 145k miles.
Its hard to describe what's happening but at around 1200 RPM's in 4th gear (50mph) with only enough throttle to keep speed, I encounter what feels like a shudder. But its very faint. Almost what feels like a rumble strip underneath me. Its not loud at all. More like a vibration. If I let off the pedal completely it goes away, If I put any pressure on the gas pedal, it goes away as well. Also once in a while when I feel this vibration I can sense the transmission ( how I refer to it) not knowing what to do. either keep RPM or gain, so it really feels like a hesitation. Same thing happens if I let off or apply pressure to the pedal? It goes away.

The only thing I've ever done is change the Tranny fluid and filter at 100k. I'm not mechanical enough to diagnose this. There are no codes being thrown at all. Could someone point me in the right direction? my hope is that I didn't get enough fluid back in it when I did the change. I read the elaborate steps to make sure the A4 is full, and thought I followed it to a T.... I am located in New England and do not know of any reputable transmission shops that are qualified to diagnose and fix this, without charging me my first born child to do it! Haha

 

I'll take a stab at this and forgive me in advance for my terminology being waaay off here. lol


I had the same exact thing issue with mine since I've owned my vette and to be honest, I just thought it was due to the gearing. Last Friday, I had her dyno'd and tuned. Luckily, the guy performing the tuning pointed out that the shudder was due to the programming, or setup due to the previous tune (from the previous owner) and said that the torque/stall converter was "loose". Not physically loose, but the set point, or whatever the term used to make it function properly. Anyways - after he re-tuned her, she runs like silk and the shudder has completely been eliminated. Hopefully, it's as simple as that for you but what you described sounds an awful lot like what I was experiencing.


p.s. I'm by no means mechanically savvy and have a lot to learn, so forgive me for my attempt to be technical here. lol Just offering my two cents! Keep me posted!

 

Thank you for this info. My car has never been dyno'd or tuned. Completely stock..... 2nd owner. I've put 125K of the 145K miles on it.

 

Having dealt with my own fair share of 4L60 whoas, I will take a guess at what is happening.

From personal experience, if you don't have the fluid level right you can end up with an issue in the Torque Converter at around 45-55mph. The converter will basically lock/unlock and you can see a variation of around 300rpm during this. If this is similar to what you are seeing, I would suggest checking your fluid level to ensure you have the transmission filled properly. I believe this is referred to as "Torque Converter Shudder". Here is a link to a forum post about this: https://ls1tech.com/forums/automatic...e-shudder.html


Beyond that, I am not sure what you would check next. The info I got was that the TC on these cars is very robust and the clutches in the TC are made of a composite that is extremely robust (locked TC dyno pulls excluded!).

Hope this helps!

Mike

 

Thanks Mike. This is exactly how it is acting. I will check my fluid level as soon as I can. Its a complete pain in the butt without a lift but I have 4 Jack stands and can get the car level and off the ground enough to go thru the procedures...

 

Fluid should be just dribbling out the fill/check level hole with the transmission warmed up to about 120 degrees, engine running, transmission in park.

Put the plug in before shutting down the engine or fluid will run out when it is shut down, resulting in a low fluid condition.

 

It could be the clutch lockup in the torque converter slipping. A lot of it is computer controlled though.

Any codes?

 

As Stated in my OP... absolutely No codes being thrown...
(other than an air pump code that I've been ignoring. P0410)

 

In 4th gear there is a clutch inside the torque converter that is supposed to lock 1:1 (no torque conversion or slip). This is to improve fuel economy at highway speeds. If this clutch fails then there may be a substantial amount of material in the fluid causing premature wear on the other parts. If the fluid looks bad and has a burnt smell then you will have problems. If the fluid is clean and you caught the problem in time then you may have gotten lucky. Most transmission shops would want to rebuild the trans after a TC failure for warranty reasons and to cover their own back in case of later trans failure.

I am not a trans specialist so I don't know about the solenoid. I just know some basics when it comes to auto transmissions. I wouldn't be able to do a proper diagnoses over the web if I was an auto trans specialist.

If you google this problem (torque converter clutch failure), the symptoms might sound familiar.