Uneven acceleration in 2nd with tiptronic car

[darrinsmith]

Hello again everyone,

Since picking up my 99 996 cab several months ago I have noticed a wierd happening when the car is accelerating in 2nd gear.

I will try to describe it as best as I can, but it's a little strange and also it ONLY happens in second.

The car is a 99 996 cab with tiptronic. It had 50,000km (about 31,000 miles) on it when I bought it in late 2005 (it now has 58,500 km on it!!!!).

When accelerating the engine revs smoothly to about 2000 rpm when it then drops back a bit, as if the car was shifting gear again, then picks up an continues to rev until the transmission shifts up to third.

The best way I can decribe it is like there is a 2nd and a half gear that kicks in, or the torque convertor suddenly locking up fully.

It is really weird, only happens in 2nd regardless of how the car is being driven (ie half throttle or full throttle- although it is more pronounced when at full-throttle).

I assume because it only happens in 2nd that it is a transmission related issue rather than an engine issue. The transmission however shifts beautifully and is smooth and responsive the pedal inputs, there is however a notiable (about 1-1.5 seconds) gap between "tipping" the steering wheel rocker switches and the transmission shifting-but I assume this is normal, I recall my old 968 tiptronic was the same, even with a brand new transmission.

I suspect that the ATF level is not correct, as this car has been sitting for a long time prior to me buying it and even though it had only done 500km since it's last service almost a year previously, had low oil and water and also has a minor oil leak.

Anyway the car is due for a service soon so I will talk to the dealer about it and get them to check the ATF level and fix the oil leak, but I just wondered if anyone had any thoughts on it?

-As a side note this is a good example of how a low-milage car can disguise gremlins that have never been fixed or noticed before. My boxster on the other hand (with 180,000km on it) is serviced every 10,000km (about 3 times a year) and runs like a swiss watch, no oil leaks nothing, totally reliable.

Cheers

Darrin

[Izzy]

My opinion is the ATF, probably due for fluid and filter change. The fluid level must be checked with the fluid at temperature. Not difficult to do if you got a temperature probe, but it does sound like needs the maintenance performed. Check the DIY for the tiptronic work, not too difficult, but can be a bit messy.

[Jack Bego]

Just curious, did you ever get this problem resolved. I have the same problem with my 1999 C4 w/38,000 miles. The dealer serviced the transmission and told me to drive it and basically forget it. The only solution they gave me was a new torque converted and pressure regulators

Thanks

Jack Bego

[david_yorkshire]

not to worry you all, but mine did this before the torque convertor exploded - no drive.

The local dealer would only replace the entire gearbox, so I went independent who changed the torque convertor.

All fine now

David

[Izzy]

Darrin,

Forgot to ask you a stupid question, do you mean from start or while on running on second gear? Big difference. From standing start, it is normal. Even though the car shows 2nd gear on the dash, it starts from first. Very briefly it does 1st, then second. Even on manual mode, when you set it to second on a stop light, and take off (when green, hopefully), it does go to 1ft, then second.

If the problem is when you are running on second, and accelerate all of a sudden in manual, it should stay on second. Otherwise it is a problem likely with low or old transmission oil.

Izzy

[david_yorkshire]

really ? mine doesn't !

1st is 1st, 2nd is 2nd;

there is always the spool up of the torque convertor when pulling off.

David

[darrinsmith]

really ? mine doesn't !

1st is 1st, 2nd is 2nd;

there is always the spool up of the torque convertor when pulling off.

David

Hi,

The car got serviced yesterday and the dealer didn't mention ATF level was low (I forgot to mention this issue, but it's going back for some more work in a week or so).

I will try again using the manual select to second and see.

I suspect it is torque convertor. My jeep does something similar (but much less noticable) when it's torque converter "locks up".

I'll report back.

Thanks

Darrin

[ScottArizona]

really ? mine doesn't !

1st is 1st, 2nd is 2nd;

there is always the spool up of the torque convertor when pulling off.

David

Hi,

The car got serviced yesterday and the dealer didn't mention ATF level was low (I forgot to mention this issue, but it's going back for some more work in a week or so).

I will try again using the manual select to second and see.

I suspect it is torque convertor. My jeep does something similar (but much less noticable) when it's torque converter "locks up".

I'll report back.

Thanks

Darrin

Hey there, I know this is an old thread but I was just wondering what happened with your tiptronic? I just had my transmission service done (new fluid, filter, gasket, etc...) and I'm now noticing this hesitation in second. Is yours still hesitating? Any info would be great, thanks.