redbird555

iTrader: (14)

HI guys I noticed an issue in my car yesterday and I think it maybe a tuning issue but I'd like other opinions. Car has an ls6 swap with bolt ons and the stock stall. If I'm cruising along in lockup at around 50mph with no accelerating just mataining a constant speed and I mash the pedal the rpms come up to around 4500 which is about where they should on the downshift to 2nd but instead of having a nice smooth downshift change I get nothing and then all of a sudden a hard hit into gear around 4500.

If I'm accelerating even the slightest bit and the the car is still in lockup at that speed and I mash the pedal the car downshifts completely normal with no problem. So the problem only exists around 50mph with only enough throttle to maintain speed. I dont think its a slipping problem though because as I said it only does it at a cruising lockup around 50 mph. If I'm doing anything from 55 on up and replicate the same conditions the tranny acts normal and hits the 2-3 shift perfectly at 6500.

I never usually jump on the car from that speed because it's kind of a dead spot but I did for whatever reason yesterday and noticed this. The only thing I did recently was had the computer tuned for the ls6 swap and then I readjusted the tire size myself in hptuners using the tire wizard which from what I understand changes some tranny perameters. However I am back at school now and wont be able to test that theory till I'm back home and have access to hptuners again.

Thanks for the help hopefully one of the transmission sponsors can chime in and lend a hand.
Dan-

EDIT: also to add the tranny shifts fine in every gear at normal throttle or even at wot it hits the 1-2 2-3 etc at the designated 6500 shifts

Detroit Gearbox

Stock converter?

Vince B

iTrader: (1)

I guess its possible that your tcc might not be releasing quick enough when you feel this. The one thing I would look at is the filter in the tcc solenoid in the pump. It might be restricted causing an issue with the exhaust of the oil in this circuit. However the one thing that concerns me is that it kind of only does this at a certain speed. It might be something that tweaking the tune might help. HTH Vince

Agreed the downshifts will be more noticeable with a factory stall.

redbird555

iTrader: (14)

yes it is still on the stock stall. Vince I assume you mean the transmission filter that can be seen right when you take the pan off? I did a full fluid/filter change in the summer of 09 which was about 20k ago so I was planning on doing another fluid change soon and will check the filter then. I agree with you in the fact it maybe in the tune because as I said as any other speed or with just the hint of throttle everything goes fine.

I'd like to hear more people's opinions but I am going to change back to the old tire size tune when I get home in a month and see what that does.

Vince B

iTrader: (1)

No there is a small screen style filter in the lockup solenoid. The blue arrow in this photo points the tcc solenoid out for you.

redbird555

iTrader: (14)

OK cool thanks and to my knowledge you unplug the solenoid, pull the retain ring out and then the solenoid should just slip out right? I dont see this as being most likely the issue because it only does it at certain speeds but it is definetley worth a look. Do you feel that it could be this or more likely tune related. I know the tire wizard changes lockup parameters so I thinkk that may have something to do with it

Vince B

iTrader: (1)

I think its more tune related. The gray solenoid is the pwm solenoid the one with the screen is located below it with the blue arrow pointing at it.

Here is another pic of the solenoid and the filter. Disregard the check ball in this picture.