Last week I installed a B&M shift improver kit in my 4L60E. The 1-2 shift was really hard, like churp my 37'' tires hard. Put about 100 miles on it when I lost all forward gears after taking off hard from a stop, but I still have reverse.

Could something have come loose that I re-installed when I put the shift improver kit in?

Is this a common problem or am I over working the trans?

EDIT*

Forgot to say this is in a Jeep Wrangler.

 

If you lost all forward gears with those tires and a shift kit set to max level as I assume it was you probably stripped the center out of the rear planet .

 

Will a built 4L60E hold up in my aplication or should I be looking at other trans?

Stock '98 LS1, 37" tires, 5.13 gears, and 4,100 lbs

 

Well I beleave so but n our lines though this may sound odd I would look at the heavy hauler series, Reason being the shifts are less agressive but still firm but with the large tires would be better to avoid the massive stress cause in your unique setup. Or optionally you might consider a 4l80e

 

How much power are you making to need 37" tires?

 

This is in a Jeep Wrangler, sorry I ment to put that in my first post.

 

Is this a 4x4 application

 

Yeah sorry I posted this on a off-road forum also and forgot to add the details when I posted it here.


This is a 4x4 Jeep Wrangler used for rock crawling/trail rides mostly but is still driven on the street .

 

That is something I would put that Towing kit in, not necessarily the Racing high-rpm kit.

 

Agreed thats why I mentioned our heavy hauler series