6.0l lq4/4l80e with 2.73 gears??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hewlett2002000 · 05-01-2009, 05:31 PM

i have a 6.0l lq4 with a 4l80e from an 01 silverado. i have the front and rear suspension from an 86 chevy pickup. i checked the rear end gears and it came out to 2.73 gears. i know thats way too high for the 4l80e but do you think it would be completely powerless? i have an 84 parts truck that is mine, i just need to go get it. would i be better off checking the gears in that and swapping the rears (again) if those are lower? any help appreciated. btw, this setup is in my 66 lwb.
thanks,
John

Pyrotechnic · 05-01-2009, 06:23 PM

You could just leave it in 3rd gear until you find a better rear end. With a 28" tire in 3rd gear at 65 MPH you will turn 2100-2200 RPM. This is basically like being in overdrive already. If you shift into 4th gear, that puts you at 1600 RPM at 65 MPH. Not ideal. Might work, might not work.

With the power of the 6.0L I don't think it will be terrible, but it's probably going to feel like you are towing a trailer all the time and you are going to leave some gas mileage and acceleration on the table.

**Captainfab** · 05-01-2009, 11:01 PM

Hey John, Have you read this recent thread?
http://www.67-72chevytrucks.com/vboa...48#post3287448

boostat4500 · 05-02-2009, 12:00 PM

Here's my experience with that setup but different gears. Keep in mind I am at a much higher altitude and ran much bigger tires however. With 4.10 gears I was at about 2k rpm at 70mph. That put enough load on the motor that the converter wouldn't lock if I hit any kind of wind or hill. I have since installed 5.13's and now turn about 2400 at 70. The motor is much happier and my gas mileage has improved. The truck the motor came out of was setup from the factory to turn around 23-2400 rpm at 70mph so that's where everything works the best. So, I would recomend driveing around in 3rd like suggested, or re-gear the truck.

pcmcobra · 05-02-2009, 02:02 PM

my 86 has a 6.0/4l80e and stock 2.73 gears.
Off the line it is a little doggy, but will still spin my 20's.
If I am rolling around 30mph and punch it, it pulls really good.
I am planning to swap in a new posi and 3.73 real soon!

454HO · 05-02-2009, 02:45 PM

I've got a 4l80e and 2.73 rear in my truck right now with a big block... not the best combo. It feels sluggish. It also raises the WOT shift point and seems to take forever to make the 1-2 shift. I don't recall how I have the TCI trans controller setup. I could probably lower the shift rpm a bit but that would not be taking advantage of the engine's powerband.

I think a 3.08 would be a noticable change in my truck. But going to either a 3.42 or 3.73 would make it downright awesome.

05-01-2009, 05:31 PM	#1
hewlett2002000 Registered User Join Date: Dec 2006 Location: Cleveland, Tx Posts: 1,619	6.0l lq4/4l80e with 2.73 gears??? i have a 6.0l lq4 with a 4l80e from an 01 silverado. i have the front and rear suspension from an 86 chevy pickup. i checked the rear end gears and it came out to 2.73 gears. i know thats way too high for the 4l80e but do you think it would be completely powerless? i have an 84 parts truck that is mine, i just need to go get it. would i be better off checking the gears in that and swapping the rears (again) if those are lower? any help appreciated. btw, this setup is in my 66 lwb. thanks, John __________________ Respect: 1. A feeling of appreciative, often deferential regard; esteem. 2. The state of being regarded with honor or esteem. 3. Willingness to show consideration or appreciation. When you fail to show consideration to others values you are showing disrespect.

05-01-2009, 06:23 PM	#2
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: 6.0l lq4/4l80e with 2.73 gears??? You could just leave it in 3rd gear until you find a better rear end. With a 28" tire in 3rd gear at 65 MPH you will turn 2100-2200 RPM. This is basically like being in overdrive already. If you shift into 4th gear, that puts you at 1600 RPM at 65 MPH. Not ideal. Might work, might not work. With the power of the 6.0L I don't think it will be terrible, but it's probably going to feel like you are towing a trailer all the time and you are going to leave some gas mileage and acceleration on the table. __________________ 1977 GMC Sierra Grande

05-01-2009, 11:01 PM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: 6.0l lq4/4l80e with 2.73 gears??? Hey John, Have you read this recent thread? http://www.67-72chevytrucks.com/vboa...48#post3287448 __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

05-02-2009, 12:00 PM	#4
boostat4500 Registered User Join Date: Aug 2006 Location: Reno, NV Posts: 346	Re: 6.0l lq4/4l80e with 2.73 gears??? Here's my experience with that setup but different gears. Keep in mind I am at a much higher altitude and ran much bigger tires however. With 4.10 gears I was at about 2k rpm at 70mph. That put enough load on the motor that the converter wouldn't lock if I hit any kind of wind or hill. I have since installed 5.13's and now turn about 2400 at 70. The motor is much happier and my gas mileage has improved. The truck the motor came out of was setup from the factory to turn around 23-2400 rpm at 70mph so that's where everything works the best. So, I would recomend driveing around in 3rd like suggested, or re-gear the truck. __________________ 1971 Suburban 4x4, LQ4 6.0L, 4L80E, etc.

05-02-2009, 02:02 PM	#5
pcmcobra Registered User Join Date: Aug 2006 Location: Florida Posts: 1,684	Re: 6.0l lq4/4l80e with 2.73 gears??? my 86 has a 6.0/4l80e and stock 2.73 gears. Off the line it is a little doggy, but will still spin my 20's. If I am rolling around 30mph and punch it, it pulls really good. I am planning to swap in a new posi and 3.73 real soon! __________________ 1986 C10 SWB 6.0/6l90e Miami...Flee it like a native

05-02-2009, 02:45 PM	#6
454HO Registered User Join Date: Apr 2005 Location: Austin, TX Posts: 1,224	Re: 6.0l lq4/4l80e with 2.73 gears??? I've got a 4l80e and 2.73 rear in my truck right now with a big block... not the best combo. It feels sluggish. It also raises the WOT shift point and seems to take forever to make the 1-2 shift. I don't recall how I have the TCI trans controller setup. I could probably lower the shift rpm a bit but that would not be taking advantage of the engine's powerband. I think a 3.08 would be a noticable change in my truck. But going to either a 3.42 or 3.73 would make it downright awesome. __________________ - Greg



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