building a 4l80e for 450hp and towing

[99burbK2500]

Who do you guys recommend to get a trans kit through that will handle 450+ hp and towing? was looking at kits from Jakes performance and also Monster transmissions. I can do the rebuild, I just don't want to waist my money and time to do it again from sub par parts. truck is a 99 k2500 suburban, should be around 450 crank, plans for boost in the future. will tow a camper when we buy one and my z28 to the race track. other than that just me the kids and wife. thanks in advance. also what do you guys recommend converter wise for a gas towing application?

 

[df2x4]

Whatever you do, stay away from Monster Transmissions. So many horror stories about those guys floating around. Jakes has a great reputation, though.

Personally though, I wouldn't worry about a bone stock 4L80E handling those conditions. They've been proven to hold 1000+ HP in drag racing applications with just a TransGo HD2 kit, no other modifications.

 

[Supercharged111]

Yeah I wouldn't bother. My dually has had the blower on for a minimum of 80k before I bought it and it's still kicking on the original trans. Wore a welding bed for around 80k as well.

 

[RDF1]

If the trans is working now. All I would do is a transgo hd2 shift kit and go.

I towed with more power than that and put 260k miles on mine.

It was stock 2004 with 45k miles on it when I bought it.
Trans go hd2 before I put it in along with a Trucool 40K cooler and wix filter. Only changed filter/fluid once At 190k mile cause the pump started whining.


For towing, I'd run the factory "BU52" converter. It's loose enough for boost and towing. But not annoying and doesn't heat up like a aftermarket stall.

I could brake stall mine to 3000 on 10psi behind a turbo 6.0.


Dialing the tune in makes the biggest difference.

When I was towing all the time I ended up setting the tune to lock converter only under 30% throttle. I could get up to speed pushing on the converter. Then ease off the throttle till the TCC locked. I hated the converter locking while accelerating.

Sent from my HiDiNg PlAcE

 

[99burbK2500]

Thanks for the info guys. I was just worried about it due to having about 270k miles on it. it does have a small flare 200rpm going into 4th at only a certain throttle input. I did flush it and run a conditioner through it about 2000 miles ago and then dropped 6 more quarts out and changed the filter. the fluid was coal black before I did the service. fluid still looks clean now. been meaning to figure out the flare into 4th but I locked the 350 up and then blew the 4.8 up I swapped in. currently putting a 10.9:1 comp 5.3 together that I plan on adding a intercooled torqstorm to. I'm glad to hear they hold big power with a HD2. ill get one of those ordered as soon as I get the truck running again. ill also look into the torque converter mentioned above.

RDF1 why did you hate the converter being locked during acceleration? wouldn't locking the converter load the engine and make the turbo spool faster? I know our 03 duramax loves when the converter locks, pulls like a damn space shuttle. of course mine will be a blower application so ill probably want the converter unlocked. also how do I identify a bu52 converter? my truck is a 99 k2500 suburban, already has the 4l80e in it.

 

[Supercharged111]

Nahh, I like mine locked as much as possible. RDF1 likely just has different driving preferences. If the trans blows up, just give it a stock rebuild with a shift kit and upgraded sprag. If it's gonna go due to mileage there's not much you can do for it externally. That flare may be solvable with a shift kit, who knows. The 4L60 has flare issues that get resolved that way.

 

[99burbK2500]

Supercharged111 you liked yours locked with the whipple powered truck?

 

[Supercharged111]

Yes, leaning on the stall especially with a trailer feels very wasteful IMO.

 

[L31MaxExpress]

With Tow/Haul active I lock mine almost immediately after going into 2nd gear and it stays locked through the upshifts even at WOT. Have not hurt it yet. Towing with an unlocked converter is wasteful and hard on the transmission. Keep it locked and downshift if you need more power. Transmission temps will stay far cooler. 350 Vortec and 4L85E with a 5.13 gear 10.5" 14 bolt and LT265/75R16 tires moves around a full size express and my travel trailer just fine.

Stock 4L85E with a Transgo HD2 and a deep pan are still alive in a friend of mines Duramax Express van. His Duramax has been making about 400 HP and 800 TQ for the past 120K. It had 50K on it when he bought it. He often tows a ~10K lbs 30' enclosed trailer too.

 

[99burbK2500]

thanks everybody for the advice!