What is the weakest part/link of the 4L60e when it comes to autobahn speed driving. Assuming we have the obvious B&M or Hayden cooler already installed. We’re talking 100-150mph for long periods of time. Hours on end. I once knew someone who moved here to Florida and had a M5, told me it was an automatic and regularly drove 150-170mph on his way to work everyday with no issues back in Germany.

we’re always talking about how to get one to handle power & last down the 1/4th mile. What about grand touring the tranny.

Cannonball run a 4L60e

 

I would think that any 4L60E, once up to speed on an autobanh with the torque converter operating normally, would be very happy. My gut feel is that its the stop and go traffic and it rowing itself through the gears that contribute to the heat around town. Don't forget the heat generated in the differential.

My M3 was very happy when I was stationed in Belgium at SHAPE HQ and made trips to Ramstein, Regensburg (my M3 was "born" there), Stuttgart or Geilenkirchen - all over Germany. Oh SO MUCH FUN on those roads. But that left lane in Germany is not for people with a slow car (or any car going slow) and I wish people here in the U.S. respected the left lanes as much as the Germans do over there. It was nothing for a 150 MPH BMW or Mercedes to appear out of nowhere in the rear view mirror!!! My wife simply could not stand it at those speeds sitting in the passenger seat but did hit the speed limiter a few times when she was driving.

Rick

 

As long as the trans is in good working order, I would think that there wouldn't be any more issues from the trans than the rest of the car. 4L60E's are not made of glass like people make them out to be.

 

Autobahn would be one of the few places where the sonnax 4th gear servo would be a worthwhile investment.
Other than that, attention to the lube circuit would be important.
I'd also be ensuring there is extra clearance in the reverse and low/rev clutch packs to minimize the drag in those while the rest of the unit is at speed.

 

what would you set the clearance at for this case?

 

I would say the 3-4 clutch set , Not for the same reasons as power shifts but simple drag ratio on them at those speeds , I would go with a 8 or 9 friction set a wide band and sonnax servo . Also I would as mentioned leave a little extra clearance probably .080 or so in the LR and REVERSE INPUT DRUMS. AND TUNE FOR WOT LOCKUP in 4th and consider an triple disc converter again the sheer drag is an issue as you speed up it will be like the car is getting heavier and heavier .