Stick Diesel Mileage? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Laoich · 11-15-2005, 07:28 PM

A stranger around here, who has an automatic '87 6.2 diesel suburban, claims to get a definite 24 mpg. Can this be true? And would it be any better with the right driver in a manual, if they have those?

Thanks if you know anything

u2slow · 11-16-2005, 02:13 AM

That's a common highway mileage figure for the 6.2L diesel with a TH700 (OD) trans. You may be able to pick up 1-2mpg with an OD manual trans. (Suburbans only came auto w/diesel though.)

You will be down in the 15mpg league with a TH400

I guesstimate 18-20mpg with a non-OD manual trans.

**special-K** · 11-16-2005, 10:47 AM

I own a`91 3/4t 4wd.That`s the last year of that design and the only year o/d was available in a 3/4t 4wd.With 4.10 gears,12.50/35" Mud tires,6.2,dual 3" exhaust,and the 4L80E,I can get around 20 mpg on the hiway at around 65-70 mph.I`d like to swap-in a NV4500 I have to the NP241 t-case.I would probably gain at least 2 more mpg.If I went to 285/75s I`d probably get it up to 24-25 mpg.Then there`s the gears...But,I`m happy with it as it is.

11-15-2005, 07:28 PM	#1
Laoich Registered User Join Date: Jan 2005 Location: Central Virginia Posts: 22	Manual/ Diesel Mileage? A stranger around here, who has an automatic '87 6.2 diesel suburban, claims to get a definite 24 mpg. Can this be true? And would it be any better with the right driver in a manual, if they have those? Thanks if you know anything __________________ 87' GMC R2500 Sierra Classic Suburban - 454 Last edited by Laoich; 11-15-2005 at 07:56 PM.

11-16-2005, 02:13 AM	#2
u2slow Web Wheeler Join Date: Jan 2000 Location: BC, Canada, eh? Posts: 388	Re: Stick Diesel Mileage? That's a common highway mileage figure for the 6.2L diesel with a TH700 (OD) trans. You may be able to pick up 1-2mpg with an OD manual trans. (Suburbans only came auto w/diesel though.) You will be down in the 15mpg league with a TH400 I guesstimate 18-20mpg with a non-OD manual trans. __________________ '66 C10 longstep - Clifford equiped '84 C20 Suburban 6.2L - awaiting 4x4 conversion '91 V3500 Crewcab - awaiting diesel swap

11-16-2005, 10:47 AM	#3
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Stick Diesel Mileage? I own a`91 3/4t 4wd.That`s the last year of that design and the only year o/d was available in a 3/4t 4wd.With 4.10 gears,12.50/35" Mud tires,6.2,dual 3" exhaust,and the 4L80E,I can get around 20 mpg on the hiway at around 65-70 mph.I`d like to swap-in a NV4500 I have to the NP241 t-case.I would probably gain at least 2 more mpg.If I went to 285/75s I`d probably get it up to 24-25 mpg.Then there`s the gears...But,I`m happy with it as it is. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

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