1999 4L80E question

[gy67]

Just bought an early 99 Chevy Silverado crew cab 2500 4x4 with 5.7 and what I think is the 4L80E trans and 3.73 gears. The truck is spotless and runs good but I'm amazed as the difference in the get it up and go compared to my previous truck which was a 98 GMC Sierra 1500 extended cab 5.7 4L60E 4x4 and 3.73 gears. My 98 could easily turn the tires over with the same style tires on them where this early 99 cannot turn the tires over to save it's life and is not nearly as quick off the line as my 98 was. I've heard these 4L80's are power sucking units but are strong and dependable. Has anyone else had similiar experience?

 

[THEFERMANATOR]

Might want to consider a tune for it as I believe teh 2500 5.7's got different tuning than the 1500's got. I believe the 2500/3500's got the 4 bolt main block and 205HP VS the 250HP the 1500's got(they only had 2 bolt main blocks though). It should have a 4L80E behind it as I believe the VORTEC only had 4L60E's in half ton trucks with torque management in them for the shifts to make them live. Look at your trans pan and see how many bolts it has in it, 16 is 4L60E and 17 is 4L80E. Also the 4L60E will be almost square whereas the 4L80E is very rectangular and rounded in the passenger side rear.

 

[gy67]

Why would GM only give the 2500/3500 205hp when the 1500 has 250hp, that's a little disheartening. It's seems you would want to reverse those numbers since 2500/3500's I would consider more of a work horse then the 1500's.Thanks for the info guys. Please keep it coming if you have it to share.

 

[WarWagon]

Don't think the 4L80E is indestructible. It needs fluid and filter changes often, like every 25K, to keep debris from wearing out the TCC piston cylinder and other valve body issues.

Work trucks vs. city slicker 1500's have some very big differences. The 1500's for 2005 had electric fans where the HD units had clutch fans. Emissions can be less strict. For example: The HP difference can have the 1500 pass you on the hill and overheat before the top, where you pass him with your truck because it was limited to max full load HP for cooling. You are going to work a 1500? This is the thoughts at GM.

 

[deejaaa]

also, an 80 will pull all day where a 60 will overheat and cough. 80 has extra cooling, stronger clutches and was made to work, not run from light to light or get groceries, although i have carried quite a few 'groceries' in my 93.
also, torque is better than horse power, when it comes time to work.

 

[THEFERMANATOR]

It all boils down to workload ratings. A 1500 truck sees less useage at high load levels so they will bump the HP up to the limit whereas the 2500/3500 trucks are rated to be held on the floor board and not die an early death. It's like the 6.0L in the late model trucks was rated at 300HP in 05 whereas the same basic engine in teh 1500SS VORTEC MAX was rated at 345HP.

 

[Joey D]

The 99 weighs more, has a taller 1st gear in the trans.

 

[gy67]

OK guys thanks for sharing all your knowledge. How hard are these to tune and what is the best way to go about it? I'm looking forward to buying a new tool (toy) and learning how to use it.

 

[THEFERMANATOR]

For tuning it I would do the 0411 PCM swap and then use EFILIVE or HPTUNERS to tune it. The stock 99 black box PCM works OK, but isn't great and is rather slow for the engine. Everybody who does the PCM swap says they run MUCH better as soon as you start it up as the 0411 PCM has twice the processor. Just bear in mind that stock you aren't going to see much gains from it as GM screwed the pooch with the VORTEC cam they put in them as well as they use a crappy intake fuel injector set-up. Even with a cam swap, porting, headers, throttle body and tuning the stock fuel injection set-up can only support mid 300's as far as fuel goes. I built one up a few years back for somebody and it ran good, but wasn't all that impressive to me in the bottem end.