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Jul 21st, 2025 | | | | Joined: Aug 2010 Posts: 5 New Guy | | New Guy Joined: Aug 2010 Posts: 5 | I have a 1966 GMC 1000 upgrading to V8 and using SM 435 trans, NP 205 transfer case, looking for overdrive unit.
I know about Gear vendors but was wondering about other overdrive unit options, also looking for deluxe windshield chrome trim. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Do not know of any OD for a 205, other than Gear Vendors, if looking for lowered RPM at cruise speeds, change diff. ratios, unless you want to change trans.'
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Jul 2017 Posts: 22 'Bolter | | 'Bolter Joined: Jul 2017 Posts: 22 | If you're still looking, Advance Adapters makes an overdrive unit called the Ranger Torque Splitter. It's a little two speed transmission that mounts between the bellhousing and the transmission. It has a 1:1 ratio and a 27% overdrive, giving you .73:1 in 4th high range. I'm thinking about using one in a Jeep project I'm working on. They're strong, compact at only 7ish inches, and everyone knows the more sticks coming through the floor, the cooler you are. This unit also allows you to engage direct and overdrive in any gear, giving you eight forward gears and two reverse gears, not a bad set up. Joe http://www.advanceadapters.com/categories/complete-units/91/
1954 Chevy 3800 Long Bed: ex-fire truck turned farmer's town run about turned 353T powered retirement project
1953 Chevy 6400: the work truck
| | | | | Joined: Apr 2015 Posts: 336 Shop Shark | | Shop Shark Joined: Apr 2015 Posts: 336 | My opinion: having more sticks coming out of the floor does not make you cooler. It just clogs up the floor.
1959 3100 Apache Fleetside
| | | | | Joined: Feb 2004 Posts: 28,674 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 28,674 | There's always the option of an air or vacuum shift for an over/under box if you don't want another shifter to play with.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jul 2017 Posts: 22 'Bolter | | 'Bolter Joined: Jul 2017 Posts: 22 | My opinion: having more sticks coming out of the floor does not make you cooler. It just clogs up the floor. Maybe it's just a Jeep thing, then. I know of one other overdrive, the Borg Warner R-10. That bolts to the back of a Dana 18 or 20, so you might be able to make an adapter plate to mate it to the 205, or swap transfer cases. That's like an actual little two speed transmission that is electronically shifted with a govenor or mechanically shifted with a cable or possibly manually controlling the solenoid. They're not produced anymore, but there is a guy that sells refurbished units and tons of parts. Joe
1954 Chevy 3800 Long Bed: ex-fire truck turned farmer's town run about turned 353T powered retirement project
1953 Chevy 6400: the work truck
| | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Who is that gentleman who rebuilds OD's?
Thanks,
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Jul 2017 Posts: 22 'Bolter | | 'Bolter Joined: Jul 2017 Posts: 22 | http://hermtheoverdriveguy.comHis name is Herm. He's really knowledgeable about older overdrive units. A lot of the units he works with are for Dana transfer cases, but the Borg Warner was supposedly popular in hot rods and what not, so I can't imagine it would be too difficult to make an adapter for it Joe
1954 Chevy 3800 Long Bed: ex-fire truck turned farmer's town run about turned 353T powered retirement project
1953 Chevy 6400: the work truck
| | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Joe,
Thanks, I had one of those OD setups in my Jeep, really liked it. Found one in a yard I have been saving.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
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