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06-08 Sonata Automatic Question

Hey guys, I'm trying to figure out what Sonata V6 5-speed auto tranny's are doing. Quite a few people (on another forum) notice that the tranny feels like it's dragging, almost like it drops into gear when you coast. Mind you, it's subtle, not a harsh deceleration like an aggressive downshift.

On my car, with A/C on (dunno about off!) when I coast down from ~60mph, at first I feel no deceleration. Then, when the car finally coasts down to ~40mph, I start feeling deceleration like the torque converter has locked. The car then slows pretty quickly from ~40-0.

Does anyone have knowledge of how the tranny is programmed WRT the lockup torque converter? At what speeds and gears is it supposed to lock and unlock?

Also, the Sonata has a tricky A/C compressor that is supposed to disengage under certain conditions. Could that be causing the slow down?

Here's my reasoning for that question:

*When the A/C compressor is engaged, the engine idles higher.

*When you are driving and release the accelerator, at some point the A/C compressor may be kicking off, in turn causing the engine idle to reduce by 100-200 RPM. That would feel like a "drag", that could be misinterpreted to be the tranny dragging. Make any sense?

Any knowledge as to whether the draggy feeling is normal or abnormal, and the cause?

Many thanks,,,

-

Bob

Reply to
Bob Adkins
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Bob, watch your tach, or slip the shifter to the right(semi-manual mode) and look at the gear indicated on the dash display.......

Reply to
Darby OGill

That used to be the case, but on my 07 Sonata GLS I-4 I have noticed that the tach stays the same place with or w/o the A/C on(at idle). I'm sure that's the ECU doing that.

Also My car coasts just great, maybe its only a V-6 problem.

Reply to
Partner

I've noticed some engine braking, but wasn't paying enough attention to know the exact circumstances to know when it was occurring. It didn't seem unreasonable, so I pretty much assumed it was normal. Like one of the other posters suggests, watch your tach and blip the gearshift over and back to see what's occurring.

Reply to
hyundaitech

Agreed, it's subtle. It's not annoying at all.

It's just that we wonder why we are getting engine braking at an unusual time. If torque converter lockup is programmed in at lower speeds, it would be interesting to know why. -

Bob

Reply to
Bob Adkins

Bob Adkins wrote in news: snipped-for-privacy@4ax.com:

It's coincidental that you guys are talking about this now. For the last several weeks I have noticed the engine braking on my '06 Sonata GLS V6 AT being more pronounced than it was before. Maybe this is a function of the life of the fluid or something similar? Not surprisingly, my mileage has also dropped a bit, but tying that directly to the engine braking is not possible statistically right now.

The weirdest thing is that I believe I have the same exact transmission in my '07 Entourage. It has absolutley NO engine braking effect that I can feel. It really is night and day compared to the Sonata.

Eric

Reply to
Eric G.

I'm not even certain it's engine braking that is caused by the tranny.

It could be that the A/C compressor is kicking off at ~40mph, causing a drop in engine idle RPM. That could possibly make it feel like it was getting extra engine braking. -

Bob

Reply to
Bob Adkins

Bob Adkins wrote in news: snipped-for-privacy@4ax.com:

True. I could be either or a combination of both.

I don't think this is the case for me as it happens with the A/C off as well and DOESN'T happen on the Entourage even with both compressors running.

Eric

Reply to
Eric G.

I think its downshifting. Mine seems to do it at 40 from 5 to 4, and 30 from

4 to 3......what does the tach and gear shift indicator(shifter in semi auto and gear shown on dash panel) tell you?
Reply to
Darby OGill

One of the purported features of the TCM's fuzzy logic in newer vehicles is that it'll monitor whether you apply the brakes when going downhill (no word on what specific data it observes). If so, it'll downshift when you're coasting downhill. If not, it won't. I wonder if clearing the adaptive values (requires Hyundai scan tool) will change this.

Reply to
hyundaitech

On Tue, 10 Jul 2007 12:45:07 -0400, hyundaitech posted:

Is the Hyundai Scan Tool available to the unwashed masses, or only to service folks?

Reply to
Oleg Lego

It's available to the masses for a small fee:

The price of Hi scan pro full kit for Hyundai is US$4,130 including reprogram kit. If you want only standard kit excluding reprogram kit, the price is US$2,600.

Thank you.

Austin CHAE

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Reply to
Steve R.

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