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Author Topic: Factory Drivetrain Specs  (Read 13251 times)

Offline Maintenanceman

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Factory Drivetrain Specs
« on: February 27, 2009, 05:38:55 pm »
I have a 1985 Chevrolet K20. Can anyone tell me where to find the factory specs (or tell me off of the top of you head, lol) for my front and rear ends, transmission, and transfer case? I know that the truck has 3:42 gears under it but thats about all I know.

TIA
Ben
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1985 Silverado K20- 355 SBC Vortec heads and a lil' cam...

Offline hilton850

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Re: Factory Drivetrain Specs
« Reply #1 on: February 27, 2009, 06:47:19 pm »
That's not much info to go off from, but here's my best guess.  Front end is a 28 spline 10 bolt with a 8.5" ring gear, rear end is most likely a semi floating 14 bolt with the 9.5" ring gear, transfer case is most likely an NP 208 aluminum chain drive unit and if your truck has an automatic transmission it's probably a TH400 and if it's a manual 4 speed transmission it's an SM465 if I remember right.  You can check your front and rear ends by simply counting the number of bolts that hold the differential covers on.  The transfer case should have a tag on the back side of it.  The transmission is easily identifiable by the transmission pan if it's an auto trans.  The TH400 has a funny shaped pan, a google search should turn up the pictures of the different transmission pans you're looking for.  If it has a manual transmission, there was only one as far as I know, and that would be the 4 speed.

I'm sure you could get a better answer if you provided a little more information....VIN number/codes from the glove box etc.
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Offline Maintenanceman

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Re: Factory Drivetrain Specs
« Reply #2 on: February 27, 2009, 07:16:38 pm »
Ill try and get the VIN when i get home tonight. Thanks alot that helped a bunch!
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Offline VileZambonie

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Re: Factory Drivetrain Specs
« Reply #3 on: February 27, 2009, 08:21:50 pm »
Just look under the truck. Look at the tag on the transfer case. Look at the transmission pan (auto) count the bolts on the differential cover.
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Offline Captkaos

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Re: Factory Drivetrain Specs
« Reply #4 on: March 01, 2009, 06:58:04 pm »
10bolt front
14bolt rear
700R4, TH350 or TH400
NP208 T-case.
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Offline Maintenanceman

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Re: Factory Drivetrain Specs
« Reply #5 on: March 01, 2009, 06:59:13 pm »
 Its a 4 speed tranny so Im assuming its a SM465
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Offline Captkaos

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Re: Factory Drivetrain Specs
« Reply #6 on: March 01, 2009, 07:15:33 pm »
Sorry, I was reading to many posts at once. 
correct, Trans will only be s SM465 if a 4speed.
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Offline Maintenanceman

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Re: Factory Drivetrain Specs
« Reply #7 on: March 01, 2009, 07:43:41 pm »
Cool thanks for all the info guys.
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Offline VileZambonie

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Re: Factory Drivetrain Specs
« Reply #8 on: March 01, 2009, 07:53:44 pm »
You never specified manual or auto. 700R4 is a 4 speed also. In 85 it could be a saginaw or warner. The Tremec was a 3spd
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Offline Maintenanceman

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Re: Factory Drivetrain Specs
« Reply #9 on: March 01, 2009, 09:09:41 pm »
Ok my bad. Its a 4 speed manual (L,1,2,3,R)
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