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**hatzie** · 12-24-2019, 11:23 AM

The LQ4 is a bulletproof Gen III engine, 130,000 ish mile parts trucks with it in the engine bay are fairly inexpensive, and it makes a fair amount of power in stock dress. The 4L80E in these rigs is a known reliable quantity as well. That's why I suggested it.

The 6L80 sounds nice til you add in the fact that you're locked into a more expensive Gen IV engine with VVT and the fact that the 6L80 doesn't have a 30 year reliability track record like the 4L80E. The GMT900 and K2 parts trucks are going to cost significantly more than a GMT800 C or K 2500 or 3500 with the LQ4/4L80E.

AFM is a known problem child. VVT might, or might not, be a problem. More parts in the valve train generally isn't a recipe for longevity.

If you have a 4x4 the NP208C & NP241C will bolt up to the 4L80 or 6L80 with a clocking ring to re-set the drop. The NP205 or NP203 will be a bit more involved but not terrible...

12-24-2019, 11:23 AM	#5
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,915	Re: Diesel engine swap The LQ4 is a bulletproof Gen III engine, 130,000 ish mile parts trucks with it in the engine bay are fairly inexpensive, and it makes a fair amount of power in stock dress. The 4L80E in these rigs is a known reliable quantity as well. That's why I suggested it. The 6L80 sounds nice til you add in the fact that you're locked into a more expensive Gen IV engine with VVT and the fact that the 6L80 doesn't have a 30 year reliability track record like the 4L80E. The GMT900 and K2 parts trucks are going to cost significantly more than a GMT800 C or K 2500 or 3500 with the LQ4/4L80E. AFM is a known problem child. VVT might, or might not, be a problem. More parts in the valve train generally isn't a recipe for longevity. If you have a 4x4 the NP208C & NP241C will bolt up to the 4L80 or 6L80 with a clocking ring to re-set the drop. The NP205 or NP203 will be a bit more involved but not terrible... __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.