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cougar9150
04-05-2011, 12:15 PM
I'm having an issue I think is related to some part of the transmission, mainly the TC. When I hit it WOT (traction control and OD off) from a standstill I bog down really bad after the 1-2 shift. It almost feels like tire spin but the tires are not spinning. Then it will slowly build back up and to start pulling like normal mid way through the RPM range 3-4k rpms. After the 1-2 shift the 2-3 shift happens w/no issues and doesn't bog at all.

It always shifts fine after the 1-2 shift at WOT and when accelerating normally (i.e. cruising, standard traffic speeds).

I do a get an occasional clunk when I let off the gas and reapply it. This happens at various rpms and I have not been able to pinpoint what action I do that causes it.

I though U-Joints at first with the clunk but the U-Joints are tight. I have no noise from the rear end, pinion flange is tight, no noises when rotating wheels when its up in the air, etc.... I have pretty much ruled out the rear end as a possible culprit but am still wary of it since I have never rebuilt that part of the drive train.

I was thinking possible slipping clutches but it doesn't over-rev like it would normally in that situation and it never does it on low to med throttle launches. The trans was refreshed about a year ago w/new bands, clutches,and seals. The fluid has been flushed once in that time and replaced w/Amsoil.

I don't have metal or more than average build up of clutch material on the magnet so I am thinking that possibly my TC is starting to fail.

The other issue I get is occasionally I'll get what I can call a surge when the TC goes to lock up under light throttle. Seems like it struggles for a second , then causes a slight jump in rpms, and then seems to settle in to normal lock-up.

Anyone have some recommended values to datalog using the SCT software to see what the tranny is doing? Kind of new using their software and still figuring my way through the tables.

Anyone else have a TC go bad and can share some of what they saw when theirs failed?

Thanks.

ctrlraven
04-05-2011, 12:41 PM
Mine does the same bog down after the 1-2 shift at WOT. Still haven't been able to figure the issue out. It's the TC locking then unlocking and locking back up or vice versa. I just had the Jmod done and changed out my TCC & EPC solenoids and replaced the pressure regulator valve in the valvebody with a Sonax grooved one and it still does it. I assume it has to do with the tune. I've got a PI 3500 converter.

http://www.youtube.com/watch?v=Sp-thPZ3wzA
Sp-thPZ3wzA

LANDY
04-05-2011, 12:49 PM
phil its got to be your tune, call me when you get out of work.

jstevens
04-05-2011, 01:40 PM
Wow, is that weird. I've never heard/seen anything like that before.

tbone
04-05-2011, 02:06 PM
It's the tune. Mine had it. The tune takes it right out and the car is awesome.

I think the occassional clunk is a little driveline lash which most cars have. Normal.

Blackened300a
04-05-2011, 02:19 PM
Its in the tune. When Powersurge and recently JDM tuned my car, they said that SCT has the TC lockup coming in around 2nd gear under WOT. On the dyno it bogged me down so we pushed it up to 90mph at WOT on my new tune from 82mph on my old tune and it will lockup around 58mph under light throttle. It much more drivable and more snappy around town. We also had it unlock at 1/4 or more throttle and under 50mph.

This is with my old tune, at the very end of the video you'll hear my convertor lock and bog the engine down just past 80mph.
LpIXLpywE3E

LANDY
04-05-2011, 04:10 PM
Paul, does it feel better now at 90mph?
I might have my tuner change mine.

Blackened300a
04-05-2011, 04:14 PM
Paul, does it feel better now at 90mph?
I might have my tuner change mine.

Compared to the 2nd gear lockup like my very first tune, its a world of difference.
I prefer having 0-90mph under power without the TC bog.

ctrlraven
04-05-2011, 08:38 PM
Here is what my TC schedule looks like. I can't really see why it bogs down after the 1-2 shift.
http://img846.imageshack.us/img846/6804/newbitmapimage2w.png

cougar9150
04-06-2011, 04:45 AM
Thanks guys, did some datalogging this morning to keep my eye on the Lockup in 2nd. I'll let you know what I see once I get a chance to review it, got 3 nice WOT blasts and noticed it doesn't happen nearly as bad when I flash/preload the TC vs stomp it from idle.

It's funny because a buddy of mine said the same thing yesterday before I read the replies. I was like no way it should be locking in 2nd blah, blah, blah and then I saw this when I got home. Look like my buddy Kevin gets a beer.

Had the tuner adjust the 3rd gear lock up schedule but never thought to look at 2nd's schedule. I will need to go see him again real soon if this is the case, more adjustments coming.

Figured w/the clunk it would be drive train noise/slop but wasn't sure so wanted to double check.