Hey guys. This is my first post but I've been lurking for a long time. I've learned a lot so far and I wish my first post would be about improving more so than fixing. Here's my set up and problem. 04 Silverado 1500 9" of lift and 36 15.50 MTZ's with 4.88 gears. And one blown tranny.

Well coming home from the dentist office today I get a pleasent surprise leaving the parking lot. A tranny slipping like crazy till it gets in to 2nd. Evertime I get going from a deadstop it slips like crazy. As I limped it home I got it up to speed on the highway and the shift into 3rd hit so hard it made the truck bounce. So now I have an overgrown paperweight in the driveway. Don't get me wrong I knew it was bound to happen sooner or later but later would have nicer.

So these are my thoughts on this. I've already been looking into getting a radix or swapping in a 408 over the winter. So I don't want another basic 4l60 from a run of the mill tranny shop. Plus I don't like where my rpms are on the highway. They seem to be in a weird spot. If I'm doing 65 mph and kick it down the truck goes from 2300 rpms to around 3000 with no real passing power. I know the 4l80 will rev a little higher on the highway so it should help when I kick it down to give me a little more passing power, right? Or would a beefed up 60 do it for me? Like a FLT lvl 4? Keep in mind I am running a heavy set of 36 15.50 tires during the summer. Any suggestions?

 

Don't waste your time on another 60e. I am finishing up my 4l80e swap. In total with trans i have done the swap for less than 1,000. I will let the other people chime in with the multiple number of 4l60e's they have went through.

 

Do it right the first time just get a 4l80 and everything you need for the conversion and be done with it. Use the search button there is alot of helpfull info on this.

 

check my sig for all my mods. Basically i have 6" lift, 35" x 12.5 tires, 4.56 gears and a Radix. The FLT 4L65E has been kicking *** since i got it and has more than handled everything i've thrown at it. Not to mention i tow a ~4.5K boat all summer. In retrospect i could have done a 4l80e swap, but at the time i didn't have the patience nor the time to do it. As of now i'm more than happy with my FLT Lvl5 65e. Thank you FLT

 

About your RPMs, did you program for your 4.88s? Your RPMs with 36" tires and 4.88 at 65mph should be around 2072 (online calculator). If i could do it over i would have gotten 4.10s w/Radix for better gas milege on the fwy. The Radix provides a lot of power to get moving, passing, and towing. I can still burn all 4 tires in 4wd from a dead stop.

 

Like you said as of now youre happy with it I was happy with my FLT level5 65e also untill last Sat.

 

Thanks guys for the help. Yes I did have it retuned twice in fact. IIRC the 2300 rpms were at 70 mph or so. I've tested the speedo against my girlfriends grand am. It was only off by a mile or two.

The tranny kicks down great at around 45 mph and pulls like a raped ape. Well as well as you can expect from my setup. But if I'm going 50 mph or higher the truck will down shift to 3rd and fall flat on its face at 3000 rpms. At this point I wouldn't dare pass a semi on a 2 lane road to save my life. Shouldn't it have kicked down to 2nd or would it rev too high to do that?

xsports33- its great to hear from someone with a similar setup running the lvl 5 and having no issues. But for the price of the lvl 5 would it be worth doing the 80 swap for a little more and have the little extra amount of security? I will have to do a little more research with the search button but the downside of that almost everyone on here is running a more street perfomance setup. ie: lowered with stockish sized tires. Which would make sense since this is perfomance trucks.net. Lol. Its just tough to know if the problems would apply to my setup. Make sense? Thanks again for the help so far guys. And sorry for the book I just wrote!