Manual to Auto swap 70 GTO
10-19-2016, 09:39 PM
#1
TECH Senior Member
Thread Starter
iTrader: (7)
Manual to Auto swap 70 GTO Looking for some opinions. I have a LS swapped 1970 GTO with a Richmond 6 speed. This trans is not the greatest (had it in the car when I first built it with a 502 bbc back in 2000 and kept it when I did the LS swap).
Lately I have been thinking about swapping to an auto, mostly for a change of pace. Car is close to 4000 pounds with driver and makes about 420rwhp and has 3.42 rear gears.
Would a stock 4L65e with a good lock up converter be enough? I like the lower first gear in the 4L65e trans...
Thanks for inputs.
Andrew
Lately I have been thinking about swapping to an auto, mostly for a change of pace. Car is close to 4000 pounds with driver and makes about 420rwhp and has 3.42 rear gears.
Would a stock 4L65e with a good lock up converter be enough? I like the lower first gear in the 4L65e trans...
Thanks for inputs.
Andrew
10-20-2016, 08:58 AM
#2
Moderator
Since the 4L65E was used in vehicles like the 6400 lb Hummer2 with an LS2 engine, I would say that Yes, a low mileage 4L65E would hold up reasonably well. Granted the truck/SUV LS2 were only rated at 325HP, but they were also rated close to 400 ft/lb torque which is the real factor in trans strength.
However, I would still recommend installing either the Transgo HD2 or the Sonnax "Performance Pack" shift kit which only require removing the valve body and not opening the trans. If you plan to regularly rev past 6000 RPM, you really should consider installing the high-RPM spring in the pump; IIRC both shift kits come with that part as an optional part to install.
These shift kits will reduce slippage during WOT shifts and thereby reduce heat and wear. If you don't install a shift kit, then you should keep at least some Torque Management enabled in the tune.
If you decide against a shift kit, install at least the Sonnax .490 Boost valve as that will increase line pressure across the board and increase the max line pressure by a bit too. Depending upon the year trans, you will need either the Sonnax 4L60E-LB1 or LB2 part. The boost valve is trivial to install after removing only the pan.
However, I would still recommend installing either the Transgo HD2 or the Sonnax "Performance Pack" shift kit which only require removing the valve body and not opening the trans. If you plan to regularly rev past 6000 RPM, you really should consider installing the high-RPM spring in the pump; IIRC both shift kits come with that part as an optional part to install.
These shift kits will reduce slippage during WOT shifts and thereby reduce heat and wear. If you don't install a shift kit, then you should keep at least some Torque Management enabled in the tune.
If you decide against a shift kit, install at least the Sonnax .490 Boost valve as that will increase line pressure across the board and increase the max line pressure by a bit too. Depending upon the year trans, you will need either the Sonnax 4L60E-LB1 or LB2 part. The boost valve is trivial to install after removing only the pan.
10-20-2016, 02:18 PM
#3
Skimmed through your build thread. Lots of high quality components in there. I personally love the shaker. Nice touch. If you need a custom converter to suit your needs, just let us know. A stalled auto would be a fun change of pace...
-Brian
-Brian