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Re: 4L60E Complete Rebuild
Posted: Thu Jun 12, 2025 8:49 pm
by The1
I do plenty of wot driving to, but you prob have more power than me, I'm stock L67 with some light porting and cam making about 8psi atm.
Best way to do it if you can build and learn then it's easy to fix yourself.
Re: 4L60E Complete Rebuild
Posted: Thu Jun 12, 2025 9:36 pm
by immortality
I think we were discussing this elsewhere but I can't remember so I'm going to leave this link here.
https://www.sonnax.com/tech_resources/2 ... ifications
Re: 4L60E Complete Rebuild
Posted: Thu Jun 12, 2025 9:45 pm
by The1
Yeh that's always been an issue, I have always turned pwm off and just commanded 100% lockup or not.
Re: 4L60E Complete Rebuild
Posted: Thu Jun 12, 2025 10:41 pm
by immortality
I've been doing the same in the tune, I just found it interesting about the excess line pressure potentially causing damage to the converter and possibly the crank thrust bearings.
There is currently a class action lawsuit for failing 6L80's/converters and it's all about the built in converter slip which GM/Holden appears to have been doing right back to the 4L60e days.
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 7:07 am
by V8fan
The1 wrote: ↑Thu Jun 12, 2025 8:49 pm
I do plenty of wot driving to, but you prob have more power than me, I'm stock L67 with some light porting and cam making about 8psi atm.
Best way to do it if you can build and learn then it's easy to fix yourself.
Nope
Problem is not in engine power
The piston of forward clutch has such design that cracks under upgraded pressure
It ckacks even in oem setups
Thats why 97+ trannys achieved updated design with steel molded pistons instead of cast aluminum
Just google -forward piston cracks
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 7:18 am
by V8fan
immortality wrote: ↑Thu Jun 12, 2025 10:41 pm
I've been doing the same in the tune, I just found it interesting about the excess line pressure potentially causing damage to the converter and possibly the crank thrust bearings.
There is currently a class action lawsuit for failing 6L80's/converters and it's all about the built in converter slip which GM/Holden appears to have been doing right back to the 4L60e days.
Some builders said that full pressure to TCC is not a problem
Some said that is
From factory TCC wont work if throttle pushed more than 60% and under medium load there is no such pressure in line
Some builders said that oem tune with TCC off at WOT prevent balooning converter even if TCC regulator blocked
I used sonnax limiter from shift kit and FITZALL valve to block TCC valve completely
And both times my tranny disintegrate torrington bearing under front planet carrier
As far as I understood this was lack of lube -not converter balooning
Now I wanna rebuild it with line to lube additional drilling and stronger 07UP bearing
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 7:55 am
by The1
i only have it locked at cruise, all other times unlocked. I did 400,000km on one this way no problems and it was stock apart from corvette servo.
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 9:12 am
by The1
What oil is everyone using? Ive been using Castrol Transmax Z for years, every 20,000km
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 10:58 am
by immortality
I use the lock up under moderate load, the stock L67 converter is too loose for my liking and I get much better acceleration with the converter locked.
I was running Penrite DX6 but was slippy when hot under full load. Went back to DXIII and it seems better but I also put in a larger reverse boost valve at the same time so that will help wth the slippy problem as well.
Re: 4L60E Complete Rebuild
Posted: Fri Jun 13, 2025 11:18 am
by immortality
V8fan wrote: ↑Fri Jun 13, 2025 7:18 am
immortality wrote: ↑Thu Jun 12, 2025 10:41 pm
I've been doing the same in the tune, I just found it interesting about the excess line pressure potentially causing damage to the converter and possibly the crank thrust bearings.
There is currently a class action lawsuit for failing 6L80's/converters and it's all about the built in converter slip which GM/Holden appears to have been doing right back to the 4L60e days.
Some builders said that full pressure to TCC is not a problem
Some said that is
From factory TCC wont work if throttle pushed more than 60% and under medium load there is no such pressure in line
Some builders said that oem tune with TCC off at WOT prevent balooning converter even if TCC regulator blocked
I used sonnax limiter from shift kit and FITZALL valve to block TCC valve completely
And both times my tranny disintegrate torrington bearing under front planet carrier
As far as I understood this was lack of lube -not converter balooning
Now I wanna rebuild it with line to lube additional drilling and stronger 07UP bearing
I was talking about the thrust bearing on the engine crank shaft. Excess line pressure in the converter pushes the converter forward into the crank and conversely the crank thrust bearing takes a beating.
Seen a few US guys killing thrust bearings with high line pressures (not specifically with our V6 motors but can't hurt to be careful).