Overdrive trans in a K20? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Smniekamp · 04-10-2017, 12:45 AM

Just out of curiosity, how would a new process overdrive trans (NV883) handle in a stock k20? Is the gearing such that it can tow decent sized loads or was it meant for 1/2 ton trucks only? Anyone have an opinion on this? There is one for sale in my area, and the O/D option would be a welcome change for me haha.

andrewmp6 · 04-10-2017, 04:57 AM

I would look in to a nv4500 swap or maybe a gear vendors overdrive on your stock trans.

D13 · 04-10-2017, 08:26 AM

The overdrive version is a 1/2 ton trans. It was never sold by GM behind anything more powerful than the 305, and never in a 3/4 ton. If you never off road or tow, and drive it like your truck is a 1/2 ton with funny bolt pattern wheels then it would be OK.

Will it work, yes, if you are gentle with it and get the cast iron version and don't have a big block and don't tow big load in overdrive and...

SunSoaked · 04-10-2017, 09:40 AM

Quote:

Originally Posted by D13

The overdrive version is a 1/2 ton trans. It was never sold by GM behind anything more powerful than the 305, and never in a 3/4 ton. If you never off road or tow, and drive it like your truck is a 1/2 ton with funny bolt pattern wheels then it would be OK.

Will it work, yes, if you are gentle with it and get the cast iron version and don't have a big block and don't tow big load in overdrive and...

Smniekamp · 04-10-2017, 04:37 PM

Thanks guys, that answers my question, if I do ever swap my trans it will probably be for a NV4500. Seems like the most reasonable option. Whats the value of one of those trans in used condition(NV4500)? I don't even know what they go for.

SunSoaked · 04-10-2017, 04:41 PM

Quote:

Originally Posted by Smniekamp

Thanks guys, that answers my question, if I do ever swap my trans it will probably be for a NV4500. Seems like the most reasonable option. Whats the value of one of those trans in used condition(NV4500)? I don't even know what they go for.

I just bought my second one last week for $500. My first one was newly rebuilt and I pad $1200 for it and a new clutch, bellhousing, etc. You are way better off to buy a truck and get everything with it.

**hatzie** · 04-10-2017, 06:49 PM

You will easily outstrip the cost and time investment of a Gear Vendors unit putting in NV4500. I've done both.
The GV unit will allow gear splits when towing big heavy stuff.

Rubble · 04-10-2017, 11:46 PM

[QUOTE=D13;7911572]The overdrive version is a 1/2 ton trans. It was never sold by GM behind anything more powerful than the 305, and never in a 3/4 ton. If you never off road or tow, and drive it like your truck is a 1/2 ton with funny bolt pattern wheels then it would be OK.
Maybe it was a Canadian thing, because I had a 82 GMC K25 with the A833 and it was factory. Also back in 83, the tool push on a rig just north of us had the same truck only a 83 model. 6.2/A833/208.... nice combo.

D13 · 04-11-2017, 05:44 AM

[QUOTE=Rubble;7912491
Maybe it was a Canadian thing, because I had a 82 GMC K25 with the A833 and it was factory. Also back in 83, the tool push on a rig just north of us had the same truck only a 83 model. 6.2/A833/208.... nice combo.[/QUOTE]

Keith shared the powertrain charts that showed it was only available with 305, 4.3, or the 6.2 diesel which has the same hp/torque ratings as a 305. So I suppose someone could order it in a light 3/4 ton. The 4wd ones have the cast iron case and would be nice as long as you didn't overload it. I thought about making that same combo, 6.2/A833/NP208, but my left knee has decided I need to sell my A833's and put in 700R4's. Ah, the joys of old age.

GM72K10 · 04-11-2017, 06:11 AM

Also had a lite duty 84 K20 with a 350 and the factory overdrive transmission, 8200 gvw.
They were made, just weren't available with the C6P option.

Smniekamp · 04-12-2017, 01:15 AM

Interestingly enough, I used to own the truck that I'd be pulling it out of, it is the 4 wheel drive cast iron model. Was strapped to a 6.2 in a 1982 K10. It was a family members that they had bought new. Granted, now it's all rusted apart and sitting in the guys backyard I sold it to. I have a camper I plan on carrying around in my bed as well as towing a lake boat with my K20 regularly so maybe it's best not to swap that specific OD trans in.

04-10-2017, 12:45 AM	#1
Smniekamp Registered User Join Date: Jan 2017 Location: Palmer, Alaska Posts: 135	Overdrive trans in a K20? Just out of curiosity, how would a new process overdrive trans (NV883) handle in a stock k20? Is the gearing such that it can tow decent sized loads or was it meant for 1/2 ton trucks only? Anyone have an opinion on this? There is one for sale in my area, and the O/D option would be a welcome change for me haha.

04-10-2017, 04:57 AM	#2
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Overdrive trans in a K20? I would look in to a nv4500 swap or maybe a gear vendors overdrive on your stock trans.

04-10-2017, 08:26 AM	#3
D13 Registered User Join Date: Feb 2007 Location: Memphis MI Posts: 1,851	Re: Overdrive trans in a K20? The overdrive version is a 1/2 ton trans. It was never sold by GM behind anything more powerful than the 305, and never in a 3/4 ton. If you never off road or tow, and drive it like your truck is a 1/2 ton with funny bolt pattern wheels then it would be OK. Will it work, yes, if you are gentle with it and get the cast iron version and don't have a big block and don't tow big load in overdrive and... __________________ 1987 2 ton 1982 250/TH350 beater in progress Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping Plus a mess o' tractors

04-10-2017, 04:37 PM	#5
Smniekamp Registered User Join Date: Jan 2017 Location: Palmer, Alaska Posts: 135	Re: Overdrive trans in a K20? Thanks guys, that answers my question, if I do ever swap my trans it will probably be for a NV4500. Seems like the most reasonable option. Whats the value of one of those trans in used condition(NV4500)? I don't even know what they go for.

04-10-2017, 06:49 PM	#7
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,912	Re: Overdrive trans in a K20? You will easily outstrip the cost and time investment of a Gear Vendors unit putting in NV4500. I've done both. The GV unit will allow gear splits when towing big heavy stuff. __________________ 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.

04-10-2017, 11:46 PM	#8
Rubble Registered User Join Date: Feb 2012 Location: Big Valley. Alberta Posts: 674	Re: Overdrive trans in a K20? [QUOTE=D13;7911572]The overdrive version is a 1/2 ton trans. It was never sold by GM behind anything more powerful than the 305, and never in a 3/4 ton. If you never off road or tow, and drive it like your truck is a 1/2 ton with funny bolt pattern wheels then it would be OK. Maybe it was a Canadian thing, because I had a 82 GMC K25 with the A833 and it was factory. Also back in 83, the tool push on a rig just north of us had the same truck only a 83 model. 6.2/A833/208.... nice combo. __________________ 1977 Chev C30 454/465/14ff DRW 1974 Chev C20.350/465/14ff " Rock n Roll ain't noise pollution"

04-11-2017, 05:44 AM	#9
D13 Registered User Join Date: Feb 2007 Location: Memphis MI Posts: 1,851	Re: Overdrive trans in a K20? [QUOTE=Rubble;7912491 Maybe it was a Canadian thing, because I had a 82 GMC K25 with the A833 and it was factory. Also back in 83, the tool push on a rig just north of us had the same truck only a 83 model. 6.2/A833/208.... nice combo.[/QUOTE] Keith shared the powertrain charts that showed it was only available with 305, 4.3, or the 6.2 diesel which has the same hp/torque ratings as a 305. So I suppose someone could order it in a light 3/4 ton. The 4wd ones have the cast iron case and would be nice as long as you didn't overload it. I thought about making that same combo, 6.2/A833/NP208, but my left knee has decided I need to sell my A833's and put in 700R4's. Ah, the joys of old age. __________________ 1987 2 ton 1982 250/TH350 beater in progress Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping Plus a mess o' tractors

04-11-2017, 06:11 AM	#10
GM72K10 Next! Join Date: Jan 2003 Location: Eastern Pa. Posts: 2,478	Re: Overdrive trans in a K20? Also had a lite duty 84 K20 with a 350 and the factory overdrive transmission, 8200 gvw. They were made, just weren't available with the C6P option. __________________ 86 K30 CUCV M1028A1 86 K30 CUCV M1028a2 dually 86 K30 C&C 6.2 4:56s, 4M, 11,000 gvw, ex fire truck, now lowboy dump More square bodies and CUCVs than I care to admit to 2020 Silverado K3500HD Work truck

04-12-2017, 01:15 AM	#11
Smniekamp Registered User Join Date: Jan 2017 Location: Palmer, Alaska Posts: 135	Re: Overdrive trans in a K20? Interestingly enough, I used to own the truck that I'd be pulling it out of, it is the 4 wheel drive cast iron model. Was strapped to a 6.2 in a 1982 K10. It was a family members that they had bought new. Granted, now it's all rusted apart and sitting in the guys backyard I sold it to. I have a camper I plan on carrying around in my bed as well as towing a lake boat with my K20 regularly so maybe it's best not to swap that specific OD trans in.

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