4L60E Lock Up Question
05-06-2018, 08:05 PM
#1
Teching In
Thread Starter
4L60E Lock Up Question My 2002 SS has a newly rebuilt 4L60E w/ mild shift kit, new 3:42 ring & pinion. Running stock 17" SS wheels with 275/40 G Force tires. Speedo re-calibrated for the 3:42 gears. It is dead on with portable Navi speed readout.
My question is as follows:
Cruising at 70 mph the tach will read between 2100/2200 rpm. It accelerates very strong without any downshift . I can feel all 4 gear changes but I was under the impression that there was a kind of electronic overdrive that would drop the revolutions about 500 rpm or so. I'm new to the game of auto transmissions having standards most of my driving years. There is a possible bug in the ointment here and that is the car was regularly street raced. I looked inside the small inspection cap at the bottom of the bell housing and saw what looks to me as welds or some kind of attachments around the flywheel teeth. That's the only way I can describe it. It just looks to me like it is not an OEM assembly.
In summary, I feel all the shifts. Very good acceleration in 4th gear without any kickdown to third. Could the ECM be programmed not to lock up into overdrive or could a modified converter do the same ? Not sure where to start and need more knowledge before having a transmission repair shop start to get their sticky fingers in my wallet. I live in Northern NJ.
My question is as follows:
Cruising at 70 mph the tach will read between 2100/2200 rpm. It accelerates very strong without any downshift . I can feel all 4 gear changes but I was under the impression that there was a kind of electronic overdrive that would drop the revolutions about 500 rpm or so. I'm new to the game of auto transmissions having standards most of my driving years. There is a possible bug in the ointment here and that is the car was regularly street raced. I looked inside the small inspection cap at the bottom of the bell housing and saw what looks to me as welds or some kind of attachments around the flywheel teeth. That's the only way I can describe it. It just looks to me like it is not an OEM assembly.
In summary, I feel all the shifts. Very good acceleration in 4th gear without any kickdown to third. Could the ECM be programmed not to lock up into overdrive or could a modified converter do the same ? Not sure where to start and need more knowledge before having a transmission repair shop start to get their sticky fingers in my wallet. I live in Northern NJ.
05-06-2018, 08:51 PM
#2
My math comes out to this:
3.42 rear x .7 overdrive (4th gear) x 336 (standard multiplier) x 70 mph / 24.91 (stock 275/40 tires as programmed) = 2260 RPM. It would be 2388 unlocked, the multiplier would be 355.
The converter you describe sounds normal as far as looks and welds.
What you need to do is cruise at 70 again, give it gas like 1/4 inch more on the pedal, you shouldn't feel anything happen. Watch the tach and lay your foot on the brake just enough to turn the lights on. The tach should go up a few rpm.
3.42 rear x .7 overdrive (4th gear) x 336 (standard multiplier) x 70 mph / 24.91 (stock 275/40 tires as programmed) = 2260 RPM. It would be 2388 unlocked, the multiplier would be 355.
The converter you describe sounds normal as far as looks and welds.
What you need to do is cruise at 70 again, give it gas like 1/4 inch more on the pedal, you shouldn't feel anything happen. Watch the tach and lay your foot on the brake just enough to turn the lights on. The tach should go up a few rpm.
05-07-2018, 09:45 AM
#4
TECH Junkie
Follows Jays advice and report back before anything else. If you are cruising at 70, use your gas pedal to keep your speed at 70 (not cruise control) and with your other foot...yes I'm telling you to drive 2 footed for a short time...tap the brake enough to turn the brake lights on. Keep your foot in the gas to stay at 70.
If the rpm's come up a little, take your foot of the brake pedal (keep it on the gas) and the rpm's should fall back down.
Oftentimes the calibration for the Torque converter lockup is meant to make it feel smooth. So this is a very easy test to see if it is locking up or not. P.S. make sure everything is up to operating temp before trying this.
If the rpm's come up a little, take your foot of the brake pedal (keep it on the gas) and the rpm's should fall back down.
Oftentimes the calibration for the Torque converter lockup is meant to make it feel smooth. So this is a very easy test to see if it is locking up or not. P.S. make sure everything is up to operating temp before trying this.