Some sort of transmission / diff / something problem?

[chris12]

Not hugely mechanically minded, so I thought I'd ask before I get my car serviced next week.

When the car is cold, once in every ten times (let's say) the car will change from first to second but I'll hear and feel this thud coming from the rear of the car. It gives a slight jerk, but it's more the thud sound which is noticeable. It is only when the car is cold, the first time the car goes from first to second.

Not SI drive related either as I've tried Intelligent and Sport mode. First seems to rev higher than normal, but I'm not sure if I'm just imagining that or not.

Not really sure if it's diff related at all, I'm just guessing. But it's definitely a feeling and sound from the rear of the car.

Any ideas?

[sheppo9]

Yours is auto isn't it?
Wife's does the same thing. I changed to synthetic diff (front and rear) oil and flushed the auto too - still does it, just not as harsh.
We'll live with it.

[WIDELOAD]

Rear uni joints maybe?

[chris12]

Yours is auto isn't it?
Wife's does the same thing. I changed to synthetic diff (front and rear) oil and flushed the auto too - still does it, just not as harsh.
We'll live with it.

Yep, mines the 5 speed auto.

[dr20t]

Hey mate

Google 5eat 2nd gear slam and you will see its a common thing

Requires tcu reset to get rid of if, but with a stock ecu / dbw tune It will eventually learn its way back around to it

It doesn't harm anything unless you're at full throttle when it does it.

Just let it warm up a little more before giving it stick

Mick

[kiwigene]

Have the same issue in mine. Just when cold and changing from 1st into 2nd.

My street has a slight rise so I have to use a few more revs after leaving the driveway.

If I really baby it, doesn't happen as badly.

[Shaheenis]

If it is TCU tune related as I think Mick is suggesting, Matt from Kido tuning may be able to get rid of it. Check with him. It may be to do with higher line pressures in the 5EAT and when the fluid is cold, changes will always be firmer when cold. Firm changes are actually better for your box than soft ones ultimately as there is less slippage = less heat. Slush boxes die from heat. I have a modified 4EAT on the old lib with upped line pressures and extra clutches. It thuds into second at low speeds but smooth and fast to shift under WOT .

[chris12]

Have the same issue in mine. Just when cold and changing from 1st into 2nd.

My street has a slight rise so I have to use a few more revs after leaving the driveway.

If I really baby it, doesn't happen as badly.

I'm on a slight incline as well. But, I feel like I can baby it and it'll still happen. Although, like I said, it doesn't happen very often.

I have the service records for the car and the previous owner mentioned it happened in the past and they did a TCU reset.

Ill see what Subaru say later this week.

Thanks for all the responses too. Glad to hear it's not anything too major, by the sound of it.

[Manaz]

I have the same issue, generally on part-throttle on a slight upward incline when the car is cold.

[chris12]

Just thought I'd update this.

Subaru said they had no bad codes come through on the car so it's just something I should monitor (like I hadn't already been...) and that if I want, I can keep the car there overnight and they can test it the next morning. I said to them that the chances of it actually happening in that one morning are very slim (1 in 10 or 15), so I'm just going to let it go. I've just had the timing belt service, ill see if it happens again and then, if it does, I'll take it it a Subi specialist and get them to reset the TCU.

[Shaheenis]

Not sure if it is the same process but on the 4EAT you reset the TCU by removing a fuse in the kick-panel. This removes historical codes from TCU. Resetting the ECU also resets 'current' TCU codes. This is for G1, S2 but hopefully may help.

This is for a Gen1, S2 but FAIK it is the same.