transmission?

[94HeavyChevy]

i have a 94 caprice classic that had the 4.3L V8 L99 in it but i recently changed to a Lt1 350 and love it..i blew the tranny and now have to get it rebuilt. i only want to do this one time so i want to do it right. how should i get it rebuilt? how much power can these trannys 4L60E handle? should i get this one rebuilt or get a different transmission? i plan on more HP mods in the future such as a supercharger so i want this tranny to be able to handle a lot of power. what should i do?

[silicon212]

The 4L60E is a good transmission, but the L99 version probably has less plates in the clutch stacks than the LT1 versions do. Just have it rebuilt, but MAKE SURE the shop you have do it, does the rebuild to LT1 standards!

If you plan on putting serious power through it, have the reaction sun shell replaced with a SPX/Filtran BEAST (also sold by TCi), and have the planetary gearset upgraded to the 4L65E 5-pinion design. Blue Bowtie has a great 4L60E page here.

[Blue Bowtie]

The Boiling Sandman is correct. A properly built 4L60 can pass 500 ft/lb all day long without so much as a whimper. If that is to be done consistently at higher RPM (like 5,200 or above) you may want to get a higher RPM pump assembly and input shell to prevent premature failure.

[94HeavyChevy]

what should i get for a torque converter? should i get a shift kit so it shifts hard?

[silicon212]

Originally Posted by 94HeavyChevy

what should i get for a torque converter? should i get a shift kit so it shifts hard?

A 2,000 RPM stall converter will help you for low end torque and you won't have a fuel economy penalty when it's in lockup.

Don't put a hard-shifting shift kit in it - the purpose of a shift kit is to help the transmission live, not to make the tires bark, twist your driveshaft, wear out your differential or break your universal joints. The well planned shift kit will only slightly affect shift at low/city speeds, but will cause more rapid engagement of the friction elements at higher RPM. Also, a hard shift kit will almost certainly lead to reaction sun shell failure unless you are using a Beast shell, as evidenced by the following photos (note, this is a ONE PIECE PART, Beast on the top and a broken one on the bottom) :





Note the added radius filet around the hub on the first one (the SPX/Filtran Beast) - it's there to prevent the sort of failure depicted in picture 2.