Gear Vendor under/overdrive

[70shortwide]

Im going to go look at a gear vendor unit tonight or tomorrow. All I know about these is how they are suppose to work. anythingt to look for? any signs that its no good? its out of the truck, guy said it worked perfect. he also said its 40% underdrive and 20% overdrive, with no direct drive? does that sound right? the price is good enough that even if I dont like it, I think its worth a try... thoughts? comments? advice?

[Redcap]

Im going to go look at a gear vendor unit tonight or tomorrow. All I know about these is how they are suppose to work. anythingt to look for? any signs that its no good? its out of the truck, guy said it worked perfect. he also said its 40% underdrive and 20% overdrive, with no direct drive? does that sound right? the price is good enough that even if I dont like it, I think its worth a try... thoughts? comments? advice?

Sounds all wrong to me or like that guy doesn't know what he is talking about. GV units should be around 20% O/D and yes, they have a direct drive.

[cdeal28078]

GV new are over 3k now right? I know they were copied from the old Volvo units. Wasn't that a Leyland OD or something like that? I always heard they were pretty dang tough and would take upwards of 500ft of torque. I have read of people using them in F350's pulling large horse trailers with them. If I ever find a heck of a deal on one I will jump all over it if I have the cash. Love to have one behind my C6
Best thing for you to do is do a complete internet search on them. There are a couple Overdrives out there.
clint

[averagef250]

GV new are over 3k now right? I know they were copied from the old Volvo units. Wasn't that a Leyland OD or something like that? I always heard they were pretty dang tough and would take upwards of 500ft of torque. I have read of people using them in F350's pulling large horse trailers with them. If I ever find a heck of a deal on one I will jump all over it if I have the cash. Love to have one behind my C6
Best thing for you to do is do a complete internet search on them. There are a couple Overdrives out there.
clint

Did you hear that from gearvendors? If you got 50K out of one using it for towing you pulled off a miracle.

[70shortwide]

I read somewhere that they are tougher in direct than in overdrive? I cant find where I read that, but is there any truth to it? My truck wont be used for towing. most of the use will be in direct drive, and I can be fairly friendly to it in overdrive.

Gear vendors website seems to think a lot of them. . seems like some people have incredible experiences with them while others work on them until they give up and pull it out...

[robroy]

Good day Jeff, Aaron, Clint and Dustin!

Jeff, thanks for bringing this topic up. I've also thought of adding a Gear Vendors Overdrive. There are probably a lot of Bumpside owners who are curious about it.

Gear Vendors claims that it's an extremely durable product. Their first sentence on their Web site reads, "GEAR VENDORS provides overdrive product to racing cars and trucks up to 2000hp and trucks towing heavy RV's up to 25,000lbs gcvw."

Yet Dustin, who is needless to say an experienced and recognized drivetrain expert, says that these are fragile machines better suited to small Volvo passenger cars, from whence they allegedly came.

The huge difference between these two claims puzzles me. If Dustin's claim is true, then how could these machines possibly hold up for even half an hour when installed in a 2,000 horsepower race car? Wouldn't Gear Vendors be guilty of flagrant false advertising, and wouldn't you expect there to be a large, poignantly unsatisfied, and vocal customer base?

Dustin, is there any possibility that you might be thinking of either a different overdrive machine, or perhaps the same machine implemented in a dramatically less durable fashion? Could Gear Vendors have honestly enhanced the machine to make it truly applicable to the applications they claim it works so well with?

Considering that I might want to buy a Gear Vendors machine some day, I'd like to find a way to reconcile the major contrast between Gear Vendor's claim and Dustin's claim. Since I respect Dustin's opinion so much, I wouldn't consider paying $3,000 for a Gear Vendors machine until I'd sorted this out!

I should probably begin by searching for everything I can find about Gear Vendors on the Web--maybe there are copious complaints therein?

Jeff, Aaron, Clint and Dustin, thanks again for discussing this topic!!!
Robroy

[cdeal28078]

I might have phrased something wrong as I have never owned one but if I could ever afford one I would do a lot of research and buy one if they seemed like as good a product as I have read. Honestly this is the first negative thing I have heard about them.
Wish I had that kind of money. I would love to keep the c6 and still have an OD. Old M38A1 military Jeep I once had my father in law had swapped in a 289 and put a Warn OD in the transfer case. You could go from normal to OD in any gear including reverse. It was sure nice to have. Would like to have something like that in my 71 F100
clint

[FreakysFords]

I've dealt with only one. It was on an 80s 6.9 F250. I didn't install it and can't say much there. I did have to replace some badly done wiring (in the vehicle, not the unit). It's owner is still using it to this day hauling farm equipment. VERY limited experience, so can't say much there.

Then there's the Volvo unit. I'm VERY familiar with this unit. They actually used it all the way to the M46 4+1 (it is the +1) in the 90s 2,7 and 9 series cars. The Volvo unit had a few redesigns over the years, but technically only listed as 3 types "early" (sometimes referred to as "A type", but never so by Volvo), "J type" (the early one used in US models" and "P type". They're all basically the same, but reliability was a factor on the "J type".

For those who don't know, I'm a "brick head" aka Volvo nut. I have an 86 744 TIC running boost in the high 20s on a "stockish" B230FT (HY35 turbo for full on racing and back to a t3/4 for plain old fun) (M block with squirters), M46 ("P type" OD) and a Ford 8.8 rear (the Volvos don't really have an answer for the drive axle). She's running secondary methanol injection post throttle body and second stage post turbo. I have literally DESTROYED many M46 transmissions, a rump load of m47s (junk IMO), a BMW transplant that was supposed to be the end all, 3 T5s and 2 T5 w/c. All of this on the same engine. All of this over the course of seven years.

I've broken 2 transmissions off at the OD unit (snapped the output shaft PRE OD) and since figured out how to brace the unit, but I've yet to kill an OD unit. I buy them up as fast as I can find them (M46's) that have "junk" OD units, only to rebuild them and sell them or install then on cars to sell. 90% of the time they had nothing wrong with them other than a solenoid "O" ring, but most common wasn't even the unit, but the relay in the car. Of the remaining 10%, some needed rebuilt (pretty much just a mini automatic trans), but most needed a reseal and fluid. I have had a few bad solenoids in there as well.

Said all that to say this: The Volvo OD unit has a bad name that it doesn't deserve. My Bride's J type has over 600k on it and is still living strong (this car get's beat on badly and was our only "truck" for 3 years).

And to say this. As small as the Volvo unit is, the GV unit is MUCH bigger. I have NO knowledge of the GV unit's reliability or durability, outside of that ONE unit. I just had to clarify that the Volvo unit is NOT the wimp it's made out to be.

Sorry for the thread hijack as this really can't be extremely helpful in the decision to go or no go on the GV unit. Just wanted to state (and show some backup of why) that if I could afford the GV unit, I would most certainly try it.

Frank

[averagef250]

Frank, I can appreciate the volvo OD being tough. However, what I have seen with my own eyes has shown me the GV is a poor choice for someone who chooses to push it anywhere near it's claimed limitations.

Circle track cars put 700 HP through toploader 4 speeds for hundreds of laps. If it were feasible, try to imagine putting that toploader behind a Big Cam 400 in a Peterbilt hooked to 70K and headed for a 6% grade. That's only 400 horsepower right?

HP is a wholeheartedly irrelevent term in geartrain torque handling ability.

The simple fact is the GV setup isn't that great of a design and spending $3000++ to add just overdrive to an old 3 speed automatic behind a carburated engine is a total waste of $3000++.

Having an overdrive automatic is neat, it's conversation piece in an old truck. Having an OD auto WITH A LOCKUP TORQUE CONVERTER is something that's actually worth mentioning and practical. A non-lockup OD automatic is pointless. Trying to cruise below 2200 or so is pointless with a carburator. The TC slips too much at lower RPM to make any overdrive gains fruitful.

You can adapt a 5 or 6 speed stick to anything pretty easily. If you must have an auto behind an old engine that never had an OD and lockup TC auto available my experienced advice is use the only OEM heavy duty 4 speed overdrive lockup TC automatic made- The 94-95 dodge 47RH. I'm not a dodge person, but I've built many 47RH's and E's. I've broken duals loose with 5K pounds of tongue weight shifting into OD with one behind a 1000 lb/ft cummins. That's power, and that tranny can handle it with grace if built right. I would have no qualms about putting a 47RH behind an old gas engine that had no other decent auto options. I'd do a bellhousing graft, have a custom billet face TC made up and never look back.

The stack of overdrive clutches and steels adequate to handle power like that has more mass by itself than a complete gearvendors overdrive. And that's only 450HP.

The GV people can make any claims they want, most of thier products sell to people that never push them hard because they don't have the power to do so (old carb engines or N/A diesels) or the vehicle doesn't weigh anything.

The original inventor of the GV never made such claims and never sold a single unit. The GV guys are great salesman, not great engineers.

Another option behind an FE would be the allison 1000 (more like 2000, 3000 in reality), since the FT's came with allison 545's in droves I'm sure it wouldn't be hard to adapt an SAE3 Allison 2000 or 3000 5 speed auto. You just have to control it which will cost a few bucks.

[FreakysFords]

Like I say, I can't really speak for the GV unit. Personally I wouldn't bother with it on a c6. I'd actually like to try one on a toploader (talk about some work. ). I don't particularly think anything's going to be worthwhile trying to get OD from a NON lockup auto.

I would love to see inside of a GV unit though.

For me the killer with the GV unit is the price. Like I say, I'd try one if I could afford it, but for me to be able to afford spending that money on a "trial", you'd have seen me on TV lookin like your typical backwood redneck (after winning the GA retirement program).

All that said, my plans for Darlin don't include an auto OR overdrive. I'm actually planning a toploader with 2.5 differential.

Sorry for the above response, I get a lil defensive hearing the GV compared to the Volvo and the Volvo unit sounding like junk by proxy.