kaos_

iTrader: (12)

Whenever my car locks up in OD it feels so nasty. my car just starts bogging down low and i have to either floor it to get out of gear or i usually just put it in 3. how can i somehow disable lockup in od? i HATE it! it feels like my tranny is going to break or something everytime it goes in to that gear at low rpm.

Predator T/A

iTrader: (7)

drive with your foot on the brake

performabuilt

iTrader: (25)

You could try raising the lockup point to a higher MPH but eliminating its not a good idea, The trans will tend to get very hot. possibly venting fluild etc. And you will suffer a considerable loss of fuel economy on the highway . Lockup should not feel bad unless you have engine misses or some converter clutch issue. Basically though when its locked up it should fel very much like and m6 car would in high gear on the highway. Lower RPM but not jerky or anything like that .

Gilbert@Ace Racing

TCC apply should be very smooth with a stock configuration and firm with a well built unit. It should not feel odd at all.

I would bet that you are feeling a cam surge if it is at slower speeds with a light throttle. If so the tranny tune needs to be adjusted to compensate for the converter / cam combination. It is not at all abnormal for that to be the case with a cam / converter swap.

You mentioned that you have to "either floor it to get out of gear or i usually just put it in 3rd." You should not have to "floor" it or give any other input than a minimal or even moderate throttle input before it releases. If something other than that is required to release the TCC then there is an issue, most likely a tuning issue.

Does it chatter?
How does it feel in 3rd gear L/U?
At what speed in O/D do you feel the L/U occur?

g

BlackHawk T/A

iTrader: (3)

Increase lockup MPH.

RevGTO

iTrader: (12)

I was annoyed with the bogging caused by early lock-up and tuning solved it for me.

blackbirdofprey

iTrader: (3)

are there any hand held tuners that will increase the lockup MPH??

'00 Formula A4, 3.23's, Lid, cat-back

Gilbert@Ace Racing

I do not know. I do know that there is more to it than just adjusting the MPH. The throttle pressure needs to be considered as well. Also the TCC release is very important in modded combinations.

Adjusting the apply to happen later is only a patch... it is not the fix.

g

ChocoTaco369

the problem with lockup on the LS1 f-body's is that it comes on with too much throttle. to disengage lockup, you have to put your foot more than halfway to the floor. when you accelerate from a dead stop, even with your foot halfway to the floor, it STILL locks up and it's like the car hits the brakes.

i had a V6 firebird with a 4L60E. the lockup used to disengage with a quarter throttle and NEVER lockup under hard acceleration. they screwed up the tuning on the LS1 models. they lock up with hard throttle (i consider ~1/2 throttle pretty hard throttle).

what SHOULD be done is to have lockup disabled under hard throttle. if possible, i would like to have my car's lockup disabled with more than 1/4 throttle. that's the way they SHOULD have been tuned - just like the V6's. the car locking up under such hard throttle is terrible for the torque converter since it generates so much wear and tear.

bumping up the mph that lockup occurs is useless. you have to make it so the car only locks up with 25% throttle or less. that'll make the car feel A LOT better. i know it because that's what it's like on the V6's.

kaos_

iTrader: (12)

crap. i can only hope my torque converter is in good shape.

RevGTO

iTrader: (12)

It is not the entire solution, but it is a part of it. You don't want to be locked up where your rpms are so low that the car lugs. You don't want to force it to unlock every time you need moderate acceleration. You want it to lock up at the point where you have enough torque available for normal acceleration in traffic.

Phoenix 5.7

iTrader: (7)

choco, u really have no clue about tuning. u can adjust the lockup MPH by the TPS

ChocoTaco369

i'm aware you can change the lockup MPH. my point is that on the stock tune, GM made the car lock up under too much throttle. that is my point. did you read my post? the mph the converter locks up doesn't bother me. i like lockup at 46 mph. what bothers me is when it locks up while i'm still deep into the throttle.

Gilbert@Ace Racing

Guys the key to remember about Torque Converter Lock Up is that it was never engineered to carry the vehicle along at a heavy throttle input. It was desigend to enhance fuel economy. Think about it.... do you really want one single 1 1/2" - 2" clutch disc to carry the weight of your car under a heavy load, say 450 hp at 3/4 throttle, I don't in my car. It will not last long at all.

Think of Lock Up as a bonus. Treat it as 6th gear in a M6 and it will last years.

In an ideal situation the converter would be allowed to lock up in 4th gear somewhere around 47 - 55 Mph below 18% throttle. And would unlock above 25% throttle. Because so many guys like to drive in manually selected 3rd gear in town, it would be locked up somewhere around 48 MPH in order to allow the converter to cool down... if it had anything other than a stock converter.

Those settings are only suggestions and should not be considered anything other than a good baseline for tuning.... the engine, trans, gear, tire combo will dictate the final fine tuning settings.

And yes, one does need to consider more of an adjustment than just MPH when tuning a transmission. Especially when it has a cam and converter in it!

Hope that helps.

g

joecar

Sounds like an engine tuning problem (too rich, too lean, spark plugs worn, air leak, or something...).

kaos_

iTrader: (12)

yeah, whenever my car gets to 1500 rpms or below it will buckle and i have to drop it to 3rd to raise the rpms or accelerate a bit. it's annoying and feels like i'm breaking my car everytime it happens. what is the solution to that? air/fuel is off? my spark plugs are fine and so is everything else, so i speculate the tune.

Gilbert@Ace Racing

Interestingly enough I just drove a customers '99 SS car, we just rebuilt his unit to our Level 2 build... cam / heads / 3600 Vig / Moser 9" 4.10's........ this car is a candidate for our tune!!!!!!

It is important to note that the converter was dissasembled at the local performance converter shop that we use while I watched, I do that for all of our performance units / builds, and the converter clutch was not damaged, looked just fine... so I know there is not a problem with the converter itself! We cut it open as a precaution as the tranny had failed several times with this converter in front of it before coming to us.

It goes into 3rd gear lock up at 30 mph... and immediately goes into a bucking condition. Tap the brake and it goes away.

When manually shifting into 4th at 45 mph there is a very slight flare as the converter is unlocking and the band is applying. And immediately the TCC locks up and it goes into the bucking condition... tap the brakes and it goes away.... this is what we refer to as cam surge.

This is a very common condition and the driveability will be greatly improved once we tune the TCC functions to his combination!

I am certain this is what the OP is experiencing.

Hope that helps.

joecar

Bucking at low RPM in high(er) gear...

locked TCC will "amplify" the probelm...
unlocked TCC places less load on engine, masking the problem;

the answer may be to change the TCC's locking MPH... but first consider the following...

if it just started happening, then something(s) "broke": air leak, injector leak, O2 sensor, MAF sensor... I'm sure you can determine if this is the case or not; even things like ECT/IAT sensors not working right could report the wrong temp. which causes the PCM to lookup the wrong AFR/timing... a scan tool is definitely required;

oh, does it eventually ping if you persist in high gear...?

on the other hand, if it's always been present, then:
- PCM may be commanding too lean;
- PCM may be commanding too much timing;
- (PCM is commanding TCC lock up too early, too low MPH);
- combination of the above;

may need to adjust those tables;

most tuners will tune for WOT operation, and some tuners will also tune for "driveability"... depends on how you've been tuned;

the answer may be to alter the TCC lock pattern, but those other things should be considered first, just to be thorough.

01Z0H6

iTrader: (63)

Hmm,,, Very good info...

I too am running a H/C Vig 3600... It drives great but i also drop it down to Drive in the city, traffic, once i get on the hwy, i throw it in OD...

Mine too bogs & bucks... But i think it is the G5X3 that i am running and it seems a little rich, need to head back out to LG and have Sean take a look...

Great thread... Good luck

z28241

iTrader: (13)

Mine seems to "buck" moments after I let off at around 45-50 coming into a 30 mph zone in OD. I usually then drop it into 3rd (D)....