TCC lock up problem

[LOT]

History on the problem. Few years ago my friend was having trouble with lock up under WOT. Locked great normal driving (Precision 5 disc). He had a billet trans built --installed the convertor on the new trans and it worked great for a while until clutches in convertor burnt. Convertor rebuilt and has worked good for a couple years or so. Sent convertor back for freshing again. Just installed and the problem is back. This 2 different trans. It locks hard @ cruise but going by DS it tries to lock but @ the top of 3rd but only a couple hundred rpm drop--not 800 as it should be. Locking with chip or manual switch--same results--must find problem or clutches will be burnt in short order. 1 ? is the solenoid seeing greater pressure against it @ WOT as compared to light throttle? We know the trans has or did have great line pressure. Is there any way the solenoid could be seeing reduced voltage? Open to any and all ideas.

 

[VIN7]

I'm going through the same thing but different converter. WOT l/u showed a very slight rpm variation shortly after l/u commanded but by 110mph the rpms matched that of unlocked runs. Fresh trans with 275+ psi pressures, fresh converter. Never had another converter in the trans. Consensus from a couple of board trans guys was that I was driving through the l/u clutch since part throttle l/u worked.

The converter is being shipped to be looked at and checked out. I'll let you know what I find out.

Mike

 

[LOT]

let me know what you find

I'm going through the same thing but different converter. WOT l/u showed a very slight rpm variation shortly after l/u commanded but by 110mph the rpms matched that of unlocked runs. Fresh trans with 275+ psi pressures, fresh converter. Never had another converter in the trans. Consensus from a couple of board trans guys was that I was driving through the l/u clutch since part throttle l/u worked.

The converter is being shipped to be looked at and checked out. I'll let you know what I find out.

Mike

Please do asap--Thanks

 

[LOT]

So you're saying

I'm going through the same thing but different converter. WOT l/u showed a very slight rpm variation shortly after l/u commanded but by 110mph the rpms matched that of unlocked runs. Fresh trans with 275+ psi pressures, fresh converter. Never had another converter in the trans. Consensus from a couple of board trans guys was that I was driving through the l/u clutch since part throttle l/u worked.

The converter is being shipped to be looked at and checked out. I'll let you know what I find out.

Mike

You are over powering the frictions? I don't know that that is the case here--I know of more than one who is putting out more power than we are. I thought that was the reason for the 5 disc. I guess we could call P.I.-probably wasted time!!!

 

[VIN7]

I don't think I could overpower the converter clutch if there was no issue with the converter. About at the same power level that I was with a stock D5, which locked up at WOT just fine...

I did a test with the lock up clutch and manual switch. In OD as soon as the trans shifted to 2nd, I locked the clutch, instantly pulled the engine down.

Left it in OD and let it lock up in 4th at 50 mph, rpm went from 2150 to 1650.

Put in D, let trans shift to 2nd, manually locked and engine pulled down, went WOT up to about 80 mph. On the datalog, WOT rpms were the same as unlocked.

Just seems that the converter clutch has an issue that doesn't allow it to hold. The converter should be delivered on Thursday, so the following week I should have some conclusive news.

Mike

Mike