FS: Over/Underdrive Unit for a Turbo 400 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68 Suburban · 03-15-2004, 01:44 PM

This is a 25% underdrive unit by Doug Nash (Now US Gear). It is basically the same thing as a Gear Vendors (Actually is rated 5000lbs more than a GV at 35,000lbs). This unit will replace the tail cone on your turbo 400 and will operate like a 2 speed rear end. It will actually give you 6 gears, but you most likely will not use all 6 gears. If you have a 3.08 rearend, with the underdrive on, it will be like having a 3.85 rearend, but you will still have the 3.08 for highway cruising. It also helps when you are towing because you can split between gears.

I was originally going to use it on my truck, but I realize it will be some time before I will get around to it, and the roller motor I am having built takes priority. It seems to be in very nice shape and was told that it was operating flawlessly when removed from a Suburban. They are known to be virtually indestructable with a rating of 35,000 lbs, but it is sold as is.

I got this for a very sweet deal and I will price it at the very sweet price of $695 plus shipping. For these units like these new, they are about $2500. Used ones on ebay usually go in the $1200+ range.

Here is a thread about this unit:

http://67-72chevytrucks.com/vboard/s...ght=underdrive

I am fickle, and I might change my mind on selling this at any time

68 Suburban · 03-15-2004, 01:55 PM

Oh I forgot to add that the tail cone can be changed for other transmissions, but I think US Gear wants about $400 with exchange for a new tail cone. So I really don't think it is worth it.

Chevy67Tk · 03-15-2004, 02:51 PM

Do you have an approx. shipping weight on it?

Just trying to figure cost of getting it here, there is a lot of pages in the atlas between AZ & PA.

68 Suburban · 03-15-2004, 04:21 PM

It was shipped to me via UPS at 68 lbs. New Mexico to Phx was $28. The zip it would be shipped from is 85323.

**crossy** · 03-19-2004, 01:37 PM

I have the same one but with a 20 or 25 % overdrive that was used for quite a while in a 55 Chevy that had 4.56 gears . it was drag raced a lot behind a blown small block and withstood the abuse. DAVE
bump

/<eystroke · 03-19-2004, 03:54 PM

Is there a way to make it overdrive? Or would it not be feasible to even try?

68 Suburban · 03-19-2004, 03:57 PM

Quote:

Originally posted by /<eystroke
Is there a way to make it overdrive? Or would it not be feasible to even try?

From what I understand, yes there is. Im not sure how though.

This is the company who's name they are manufactured under now:

http://www.usgear.com/dual_range.htm

/<eystroke · 03-19-2004, 04:08 PM

Quote:

What is the ratio of the Dual Range?
The Dual Range is available in two different models: Direct and 20% Overdrive or Direct and 20% Underdrive. The 20% overdrive ratio is .80 and the 20% underdrive ratio is 1.25.

Looks like it is two separate models.

68 Suburban · 03-19-2004, 04:35 PM

Quote:

Originally posted by /<eystroke

Looks like it is two separate models.

They do sell them as two seperate models, but if you call them and ask if one model can be switched to the other, their answer will be yes. They change one of the gears. I think if someone was going to go that route, it would be easier to get a different rear end to achieve the same thing.

68 Suburban · 03-19-2004, 04:41 PM

Someone wanted to see the inside that slides on the output shaft of the transmission. Here is the picture:

68 Suburban · 03-22-2004, 06:06 PM

tentatively sold, thanks

03-15-2004, 01:44 PM	#1
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	FS: Over/Underdrive Unit for a Turbo 400 This is a 25% underdrive unit by Doug Nash (Now US Gear). It is basically the same thing as a Gear Vendors (Actually is rated 5000lbs more than a GV at 35,000lbs). This unit will replace the tail cone on your turbo 400 and will operate like a 2 speed rear end. It will actually give you 6 gears, but you most likely will not use all 6 gears. If you have a 3.08 rearend, with the underdrive on, it will be like having a 3.85 rearend, but you will still have the 3.08 for highway cruising. It also helps when you are towing because you can split between gears. I was originally going to use it on my truck, but I realize it will be some time before I will get around to it, and the roller motor I am having built takes priority. It seems to be in very nice shape and was told that it was operating flawlessly when removed from a Suburban. They are known to be virtually indestructable with a rating of 35,000 lbs, but it is sold as is. I got this for a very sweet deal and I will price it at the very sweet price of $695 plus shipping. For these units like these new, they are about $2500. Used ones on ebay usually go in the $1200+ range. Here is a thread about this unit: http://67-72chevytrucks.com/vboard/s...ght=underdrive I am fickle, and I might change my mind on selling this at any time __________________ Just sitting here contemplating contemplation.

03-15-2004, 01:55 PM	#2
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	Oh I forgot to add that the tail cone can be changed for other transmissions, but I think US Gear wants about $400 with exchange for a new tail cone. So I really don't think it is worth it. __________________ Just sitting here contemplating contemplation.

03-15-2004, 02:51 PM	#3
Chevy67Tk Registered User Join Date: Mar 2003 Location: PA Posts: 349	Do you have an approx. shipping weight on it? Just trying to figure cost of getting it here, there is a lot of pages in the atlas between AZ & PA. __________________

03-15-2004, 04:21 PM	#4
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	It was shipped to me via UPS at 68 lbs. New Mexico to Phx was $28. The zip it would be shipped from is 85323. __________________ Just sitting here contemplating contemplation.

03-19-2004, 01:37 PM	#5
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	I have the same one but with a 20 or 25 % overdrive that was used for quite a while in a 55 Chevy that had 4.56 gears . it was drag raced a lot behind a blown small block and withstood the abuse. DAVE bump __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

03-19-2004, 03:54 PM	#6
/<eystroke Registered User Join Date: Jul 2003 Location: North Texas Posts: 265	Is there a way to make it overdrive? Or would it not be feasible to even try? __________________ '69 C/10 Short Wide 350/400/AC/Tilt/Tach

03-19-2004, 04:41 PM	#10
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	Someone wanted to see the inside that slides on the output shaft of the transmission. Here is the picture: __________________ Just sitting here contemplating contemplation.

03-22-2004, 06:06 PM	#11
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	tentatively sold, thanks __________________ Just sitting here contemplating contemplation.



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