Gearvendor Overdrive

airjammer

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Howdy all, been lurkin on the site for a bit, lots of good info.

I would like to get your input on the gearvendor overdrive, doesnt matter good or bad experiences, it's all good info.

I'm drivin an '03, 7.3L, ZF6, CC, 4WD.

Thanks
 

JDub

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Know a few guys running them. Seen good and bad. Better mileage and gearing options for towing. But they don't seem to hold up to much torque for long. One good friend has one in his 96' with Stage II injectors and he had enough troubles with his that he bought an extra unit and hauls it in his trailer everytime he takes long road trips.

Not sure changing out an overdrive unit on the side of the road while on vacation is something I'd be interested in.
 

uncool

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Since you have an 03, that looks like you converted to a dual rear wheel setup, you most likely have 3.73's gears in it. I would recomend against it. I ran one for a while with 4.10's and it was on the edge of being to tall geared. 4.30's or 4.56's is where I think the OD would shine. I never had any issues with mine, but I did do a few teawks to it before I put it in. Billet steel planetary set was the only real upgrade.

I now run 3.73's in my dually with 33" tall tires and have the best of both world personally. I cruise at 1900 in OD vs 2100 with the 4.10's, and did not lose any of my towing ability. My turbo is not quite as happy with the 200 less RPM towing, but who in there right mind tows with a 76mm inducer turbo. Oh wait, I do.

Last long trip, I averaged 17 mpg over 3500 miles.

Had no issues with the paultry 550 rwhp that I put through it on a daily basis.
 

RubberDuck

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I love my gear vendors. I have 4.10's with the 235 tires. The double overdrive is what I mostly use it for. Pulling heavy I use it to split 3-4th.

I do love it, but I've ruined 2 of them because I used the wrong gear oil. But since I've gotten my head out of my ass and use the fluid they recommend, it's been smooth sailing. I pull heavy with it, and in racing situations I shift it WOT with no clutch. I call it my cheater gear. LOL

I don't think torque is to big of a concern. It will handle anything you can throw at it going foward. You just have to remember when you are slowing down, it WILL turn off when you get to a certain speed. These things engage with hydrolic psi from a pump that is spun by the drive shaft. Mine usually turns off around 25mph. And since it is a clutch mechanism, you really don't wanna motor brake with the od engaged. The last one I ruined the reverse cone clutches went out. So when you would let off the throttle the motor would go to an idle like and auto because the reverse clutches were smoked.

Since then, I have found a guy that sells all the parts to rebuild the units for $250, or will rebuild them for $500. They are a servicable part, so at some point the clutches will wear out. They are not all gear like say a US gear unit. But they are no longer in business. I believe GV is the only external OD company left on the market.

So there, that's my take on the GV. I love mine, and will put one on every truck I own. As long as you remember there are some, not many, but some limitations to what it can do.
 

imelmo

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Sub'd. Thinking about possibly putting one in my '03 6.0 to get some top speed back since I'll have smaller than stock tires.

.
 

Corb@CorbinShipping

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Heavy Haul runs one on his 08 450 with 4.88s automatic and loves it. I bought one from a friend of his (still havent been able to instal it, need my other truck back so I can take it apart) But he tows heavy, up to 30 K, with it engaged, and changed the oil out every 5,000 miles, and has no issues. He has advised, same as have here, about downhill grades... def disengage it.

I dont tow nearly as heavy. The biggest thing I pull is my 18K 5th wheel, and that is only once or twice a month. But I have 4.30 gears in my 450 with 33.4 inch tires. I would say if you have 3.73s, you might be asking alot of the other parts in your driveline.

I will be installing mine in the next month or so, but I only plan on using it when I am very light, or empty. Towing heavy for me is not about speed. I am not comfy with 30 K gross, at 80 mph... 65 is my highway cruise speed when I am loaded down, and that puts me right where I need to be in the RPM band, So I wont use it when I am pulling the camper. But my boat, or a smaller load? Hell yeah! Empty? Hell yeah! Getting 14.5 MPG unloaded now, shooting for 20 MPG unloaded with the GV!
 

lincolnlocker

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i've often thought of getting a GV... 80mph across the country at 2500rpm's gets annoying with a 38r... still pulls off 14.5mpg though.
 

Corb@CorbinShipping

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so what are the rpm's at 60-65 with 3.73 gears

on the 450, 65 with 4.30s and 33.4 inch tires is 2150

on the 250, 65 with 3.55s and 34 inch tires is 1700 (factory)
on the 250, 65 with 4.10s and 35.5 inch tires is 2000 (now)

these are all ovserved on factory gauges, so, they are that accurate..... LOL

i would imagine 3.73 is about 1850-1900 with 34 inch tires, but I never had 3.73s, so I cant say for sure, the others are #s that I have had before, or currently have.

I looked into using lower gears, like 3.73s on the 450... problem is, that is a dana 110, and gearsets for that monster are over 2,000 bones.... and if I dont like it, i am stuck with it. I got my GV for 1600 bones, new, and it will likely cost about 600 bones to install. Then, I will have MY CHOICE of what RPM I wanna cruise in... for towing, I would hate to have my 5th wheel, 18,000 lbs, up hill, in the mountains, at 55 mph speed limit with 3.73s.... with my 4.30s, that scenario is no problem... 32-34 lbs of boost, 1450 egt, maybe creep up to 1550 towards the end of the hill, but I dont mind hitting #s like that for short time frames. same scenario with 3.73s, I dont think OD would hold, and if it did, egts would likely be much higher. I just want another gear for light loads, or empty running. It is supposed to drop rpm by 400-500, depending on your current gear set.
 

TARM

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Since you have an 03, that looks like you converted to a dual rear wheel setup, you most likely have 3.73's gears in it. I would recomend against it. I ran one for a while with 4.10's and it was on the edge of being to tall geared. 4.30's or 4.56's is where I think the OD would shine. I never had any issues with mine, but I did do a few teawks to it before I put it in. Billet steel planetary set was the only real upgrade.

I now run 3.73's in my dually with 33" tall tires and have the best of both world personally. I cruise at 1900 in OD vs 2100 with the 4.10's, and did not lose any of my towing ability. My turbo is not quite as happy with the 200 less RPM towing, but who in there right mind tows with a 76mm inducer turbo. Oh wait, I do.

Last long trip, I averaged 17 mpg over 3500 miles.

Had no issues with the paultry 550 rwhp that I put through it on a daily basis.


Come on you do not actually tow with a engine that can make that kind of power!?! Didn't you get the memo that it can not be done and certainly not with any hint of reliability:doh:

More On topic: The info you gave me on the GV internals was a real eye opener when we talked way back.
 

Heavyhaul

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on the 450, 65 with 4.30s and 33.4 inch tires is 2150

on the 250, 65 with 3.55s and 34 inch tires is 1700 (factory)
on the 250, 65 with 4.10s and 35.5 inch tires is 2000 (now)

these are all ovserved on factory gauges, so, they are that accurate..... LOL

i would imagine 3.73 is about 1850-1900 with 34 inch tires, but I never had 3.73s, so I cant say for sure, the others are #s that I have had before, or currently have.

I looked into using lower gears, like 3.73s on the 450... problem is, that is a dana 110, and gearsets for that monster are over 2,000 bones.... and if I dont like it, i am stuck with it. I got my GV for 1600 bones, new, and it will likely cost about 600 bones to install. Then, I will have MY CHOICE of what RPM I wanna cruise in... for towing, I would hate to have my 5th wheel, 18,000 lbs, up hill, in the mountains, at 55 mph speed limit with 3.73s.... with my 4.30s, that scenario is no problem... 32-34 lbs of boost, 1450 egt, maybe creep up to 1550 towards the end of the hill, but I dont mind hitting #s like that for short time frames. same scenario with 3.73s, I dont think OD would hold, and if it did, egts would likely be much higher. I just want another gear for light loads, or empty running. It is supposed to drop rpm by 400-500, depending on your current gear set.

Couldn't of said it better myself. I change my oil every 10,000. Its 20 bucks for a bottle of fluid and done. I have 80,000 on the unit now. Pushing around 500 hp while towing.
 

Monster Stroke

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We have an 01 550 with 5.18's I think?? Without the gear vendor it redlines at 70mph in OD. The gear vendor helps the most just to get the rpm's down for highway cruising but we've gone through 3 of them in only 60k miles...

We didn't realize until this last one that the tow rating was so low... The 550 has a way higher hauling capacity than the gear vendor is rated for so we think that's whats killing them...
 

lcough

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I have a 99 550 with 4.88. I’ve been running the GV for a couple years with no issues other than a lot of clutch material in the oil. The GV gave me the perfect cruse ratio. I went from 70 mph @ 2700rpm down to 2050rpm. I have been running the GM#12346190. I serviced it last week and GV recommended Lucas Synthetic 75W-90 as an alternative. I made it about 30 miles pulling trailer and jeep. On the 1-2 shift, medium throttle, very loud pop and engine rev'ed. I went back to the GM lube hoping the Lucas let the clutches slip. No good news. We tore it down and it had grenaded the sprag.

The unit is weak for the 1000hp rating they claim. I have heard the following from them…Don’t tow in OD it will burn up the transmission. The GV is strong enough, the oil just shears. 550’s eat those units with full throttle launch and a loaded trailer. It’s the driver’s fault.

I don’t always get to start off downhill!

So now the dilemma is do I spend the $1,200 to get a reman (with shipping), that I am scared will let go. Do get a spare to carry with me? GV said I can’t tow in DOD. I would be better off with pulling the unit and getting a longer drive shaft.

I would spend the extra $5-$10/quart and stay with the GM#12346190. I think the Lucas GL-5 is too slick. I believe with the reduced clutch friction, the sprag could not hold.

I’m happy for those who have had good luck, I need something stronger.
 

Corb@CorbinShipping

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I have a 99 550 with 4.88. I’ve been running the GV for a couple years with no issues other than a lot of clutch material in the oil. The GV gave me the perfect cruse ratio. I went from 70 mph @ 2700rpm down to 2050rpm. I have been running the GM#12346190. I serviced it last week and GV recommended Lucas Synthetic 75W-90 as an alternative. I made it about 30 miles pulling trailer and jeep. On the 1-2 shift, medium throttle, very loud pop and engine rev'ed. I went back to the GM lube hoping the Lucas let the clutches slip. No good news. We tore it down and it had grenaded the sprag.

The unit is weak for the 1000hp rating they claim. I have heard the following from them…Don’t tow in OD it will burn up the transmission. The GV is strong enough, the oil just shears. 550’s eat those units with full throttle launch and a loaded trailer. It’s the driver’s fault.

I don’t always get to start off downhill!

So now the dilemma is do I spend the $1,200 to get a reman (with shipping), that I am scared will let go. Do get a spare to carry with me? GV said I can’t tow in DOD. I would be better off with pulling the unit and getting a longer drive shaft.

I would spend the extra $5-$10/quart and stay with the GM#12346190. I think the Lucas GL-5 is too slick. I believe with the reduced clutch friction, the sprag could not hold.

I’m happy for those who have had good luck, I need something stronger.

Damn... How much are you towing? Heavyhaul is moving 30 K with a 450, and his has lasted for years... Through Wyoming....
 

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