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Racingsnake
Racingsnake Reader
2/24/24 8:44 p.m.

I've fitted a Gear Vendors overdrive from an RV to my Plymouth station wagon and need to wire it up. I think I just need to send power to one side of the solenoid and ground the other to make it work. Pretty sure it's not polarity sensitive but figured I'd ask to see if anyone can confirm. What sort of current does it pull in overdrive?

Thanks

Streetwiseguy
Streetwiseguy MegaDork
2/24/24 9:33 p.m.

Look for the wiring diagram for a 1970 Volvo...

Yes.  Power on one, ground on the other.  The only safety thing a guy might want is to lock out the possibility of it engaging it in reverse.  They really, really hate that.

The hydraulic pressure comes from a piston pump on the input shaft, so it probably won't be good for it to engage in first gear.  2nd over can be a nice split.

A 401 CJ
A 401 CJ GRM+ Memberand SuperDork
2/25/24 12:33 a.m.

That a 'foe foety'?

Appleseed
Appleseed MegaDork
2/25/24 10:17 a.m.

A Gear Vendors...from an RV?!? Tell us more.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/25/24 11:41 a.m.

The solenoid on mine did not have a polarity.  Mine came from Gear Vendors with the little control box, which was really nice.  It had a 3 position switch so it could operate automatically (with a reluctor feed from the speedo), manually with a foot switch, or always off.  It also had a reverse light trigger that kicked it off.

IIRC, it didn't need anything to tell it to turn off because as you slowed down, the pressure dropped and self-disengaged.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/25/24 11:43 a.m.
Appleseed said:

A Gear Vendors...from an RV?!? Tell us more.

From what I understand, some RV companies added them.  During the smog era when a big block made 185 hp, the combatted that with 4.56 or 4.10 gears and then added the OD to try and save a few drops of fuel.

wspohn
wspohn UltraDork
2/25/24 11:58 a.m.

A number of Jensen Interceptor owners have fitted those behind their 440s.  The ones I have spoken too really like them.

Appleseed
Appleseed MegaDork
2/25/24 1:02 p.m.

In reply to Curtis73 (Forum Supporter) :

We need to make a list. This is a potentially awesome source of cheap GV Overdrives.

Racingsnake
Racingsnake Reader
2/25/24 1:03 p.m.

Thanks for the comments and info. Yes, it is a 440, moves the wagon along much better than the 318 that was in it! I did get a control box and some wiring with it but for now I think just a toggle switch with a warning light to remind me it's engaged should do the job. I did find that the solenoid only draws about three amps so no need to worry about relays or anything 

ShawnG
ShawnG MegaDork
2/25/24 1:22 p.m.

Are these things the same as the Volvo units that Streetwiseguy mentioned?

More curious than anything.

Racingsnake
Racingsnake Reader
2/25/24 1:52 p.m.

They're very similar but I think they are a bit bigger and heavier duty

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/25/24 5:09 p.m.

From Gear Vendors' website:

 GEAR VENDORS did not invent overdrive or the original patents on our product. DeNormanville (maybe the most famous transmission designer ever) created the original product which, GKN (a 6 billion dollar/year public automotive conglomerate) acquired to produce overdrives for Ford and Volvo. GEAR VENDORS became a licensed manufacturer for GKN in 1979 and started applying racing expertise to the original products. With those improvements in materials, manufacturing techniques, and racing development came renowned success. Now (30 years later) we have bought out GKN’s overdrive division and all rights to the DeNomanville designs to gain ultimate control of quality and production.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/25/24 5:12 p.m.
Appleseed said:

In reply to Curtis73 (Forum Supporter) :

We need to make a list. This is a potentially awesome source of cheap GV Overdrives.

This isn't really a list, more of a place to start, but their website says this:

Prior to the factory overdrives becoming available many vehicles in the 1980’s and early ’90’s came factory equipped with the GEAR VENDORS as either optional or standard equipment. These manufacturers included Allegro, Fleetwood, Monaco, Executive, and Rexhall motorhomes, GM’s Callaway Corvette, Volvo passenger cars and Ford Diesel Transit vans.

Appleseed
Appleseed MegaDork
2/25/24 5:52 p.m.

Those free RVs might be worth investigating .

Streetwiseguy
Streetwiseguy MegaDork
2/25/24 6:14 p.m.

The Volvo units were a Laycock type J unit.  These one are a bit larger, but pretty much identical in operation. 

Rons
Rons GRM+ Memberand Dork
2/25/24 6:17 p.m.

I believe Tim installed a Gear Vendors unit on the ramp truck

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/26/24 11:40 a.m.

I had one in a 66 Bonneville behind a TH400 and Caddy 500.  I loved it.  They're so simple, and they're tested up to something like 2000hp and 2000tq with no hint of damage.

If you can find one cheap, they're awesome.  I bought mine new and never really recovered from the sticker shock.  In hindsight for me, it would have been the same cost to do a 4L80E with a controller, but I was hell-bent on analog for that build.

Loren_SD
Loren_SD New Reader
2/26/24 4:10 p.m.

I wonder out of curiosity if/how they might be similar to the Doug Nash unit on the C4 "4+3".  

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/26/24 4:25 p.m.

In reply to Loren_SD :

Similar in that it's an overdrive that goes behind the transmission, but otherwise completely different animals.  The DNE2 was a Doug Nash original and used very similar parts to a truck 2-speed rear axle and has a 30% OD.  It uses a motor to engage.  It was eventually bought by US Gear.  The GVOD is a planetary two speed that uses a hydraulic pump and solenoid to provide pressure for engaging a 28% OD.

ShawnG
ShawnG MegaDork
2/26/24 4:38 p.m.

The Doug Nash 4+3 was a 4-speed manual (Super T10) with parts derived from a TH350 hanging off the back of it.

 

Loren_SD
Loren_SD New Reader
2/26/24 10:26 p.m.

I had a DNE2 with the electric-motor-driven shift fork and what was essentially a set of 4 countergears behind a SM465 truck manual once but the 4+3 appears to be not like that, but rather similar to the GV with a hydraulic pump and "pistons".

A 401 CJ
A 401 CJ GRM+ Memberand SuperDork
2/27/24 8:03 a.m.

I did some math once based on expected MPG gain at contemporary gas prices and, as probably no surprise to anyone, if buying new unit like Curtis did, it'll take most of the lifetime of a new vehicle to earn it back.

But they are nice.  Just hard to find used.

grover
grover GRM+ Memberand Dork
2/27/24 9:31 a.m.

In reply to A 401 CJ :

Some things need more value add mathing than just the mpg imo. It's stressful to hear a motor humming at high rpm's that isn't a vtec or other normally high strung model. How much value does the lower rpm and related stress/wear and tear add up to? 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/27/24 10:04 a.m.
A 401 CJ said:

I did some math once based on expected MPG gain at contemporary gas prices and, as probably no surprise to anyone, if buying new unit like Curtis did, it'll take most of the lifetime of a new vehicle to earn it back.

But they are nice.  Just hard to find used.

hard to find, and they don't lose much value.  I sold mine for almost as much as I paid for it.

But quite honestly, I think they could be abused for 1 million miles and still look new on the inside.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
2/27/24 10:07 a.m.
grover said:

In reply to A 401 CJ :

Some things need more value add mathing than just the mpg imo. It's stressful to hear a motor humming at high rpm's that isn't a vtec or other normally high strung model. How much value does the lower rpm and related stress/wear and tear add up to? 

That would be an interesting metric to know.  Like... if you have a the same engine in a 2wd chevy pickup with 3.27 gears, does it last any longer than a 4x4 with 3.73s?

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