3.55 gears vs 4.10s with gear vendors

[Old Goat]

I have a lot of GV Threads I saved in a Folder, I know I will
never find them again looking for one.
I have one where the guy installed an external Filter and a Pump.
I`ll edit and stick it in here when I find it.
Here is a good one with the guys install and experience.

My Gear Vendors experience (with pics) - Dodge Diesel - Diesel Truck Resource Forums

3rd Gen High Performance and Accessories (5.9L Only) - My Gear Vendors experience (with pics) - I would like to share with everyone my experience with my latest toy. I bought a Gear Vendors auxiliary overdrive (http://www.gearvendors.com). It is basically a small second transmission bolted...

www.dieseltruckresource.com

Found this video installing a GV on a 86 F-350.

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EDIT}-- I guess I didn`t save the link where the guy installed
a pump and Filter to extend the life of the oil.
I must have 40 or so GV links in a Folder I saved when I come
across one I know I`ll never find again.
Did a bunch of Googling, and found a thread on some forum
where the guy posted some pictures, but they have been deleted.

Goat

 

[12pilgrim]

F250HD, 4.10s with T19 4spd, NA... 2500 rpm is 60mph! Mine screams angrily at anything past 55

 

[WrenchWhore]

Personally, I really like the gearing I have with 35's, 3:54, T19, and (093). Mind you I haven't pulled heavy with it. It has a decent highway speed/RPM for me (65). Any faster than 70 MPH the brick shape starts to really kill efficiency. I usually start in first gear anyways. First could easily get a big trailer moving with minimal effort.

One thing I did learn about this setup is 93 MPH is max speed when the pump de-fuels. Haha

 

[Nero]

I meant to follow up with this last night, but forgot due to it being a bit chaotic.
70mph at 2500rpm even, able to maintain speed on decent grades with turbo, studs and intercooler. Idi geared zf and 4.10s with fully loaded camper in the back, bed weight about 5k

 

[IDIBRONCO]

F250HD, 4.10s with T19 4spd, NA... 2500 rpm is 60mph! Mine screams angrily at anything past 55

That's what happens with these when they have 4.10s and no overdrive.

 

[WrenchWhore]

That's what happens with these when they have 4.10s and no overdrive.

I can't imagine how bad a C6, stock tires, and 4:10's would be at modern highway speeds. Just screaming down the road lol

 

[Ruffnek7tree]

My wording wasnt clear. Trying to back up against any kind of resistance, whether it is backing a load, or a rock, or a curb.... Even with the gv turned off, can can break it internally.

They also hang way out there, and on trucks with 1 piece driveshafts, wheel hop can break them.

Have seen the first way happen many times, the second only a couple.

So, I have been doing research on this, and I haven't found much in the way of people having this problem, or at least griping from it lol.. it seems like the ones that had problems had the unit engaged and the wheel speed made the unit try and shift.. idk, I've never had one, but have you had one that has done this? Just trying to learn here

 

[Black dawg]

So, I have been doing research on this, and I haven't found much in the way of people having this problem, or at least griping from it lol.. it seems like the ones that had problems had the unit engaged and the wheel speed made the unit try and shift.. idk, I've never had one, but have you had one that has done this? Just trying to learn here

Have not personally broken one either way, but like I said, have seen both happen On trucks I have worked on. I have seen plenty of threads on the sprag clutch getting broken, from backing, or from using them during engine braking. Funny, when I search now nothing comes up.....

 

[The_Josh_Bear]

Have not personally broken one either way, but like I said, have seen both happen On trucks I have worked on. I have seen plenty of threads on the sprag clutch getting broken, from backing, or from using them during engine braking. Funny, when I search now nothing comes up.....

It's the beginning of the GVOD AI cover-up...

 

[Cant Write]

I don’t have the experience these guys do but after reading their input. And you saying you mostly run empty, I’d be apt to have 2 rigs if you have the space and the budget.

Your DD (gear it for 75), then your tow rig (gear it for 65)

@silexis has the exact setup you’re talking about and he said that the splits don’t match up the way one would hope....(btw awesome you have an IDI running around Boulder)

@Black dawg has personally seen them break, I love to engine brake and everyone needs to reverse..... that would be a deal breaker for me.

I’m getting old too, I like stock height pickups with 1-size larger tires (32-33) and I’m happy at 72-75 mph if I must drive the interstate.

Good luck, this thread has been a great read from so much experience!!

 

[Ruffnek7tree]

@Cant Write
This truck is kinda the substitute for my normal truck, my 01 powerstroke, it's stock 3.73 gears with 38s, and it cruises nicely and tows pretty decent for a mostly stock engine, but I have to take it off the road for a while, needs more maintenance than I can do if I drive it all the time, fixing a bunch of fiddley things, remove rust from the underside before it gets worse, fix leaks, swap 05+ front suspension, etc..

@Black dawg
I imagine that a lot of the breakage comes from neglect and abuse, I have seen some threads about that, but I got the impression that they tended to use their right foot more than they should lol..

I think I'll take a chance on this eventually, seems like it could be the best setup, because I still will need to tow with this truck as well as drive it unloaded

 

[IDIBRONCO]

I can't imagine how bad a C6, stock tires, and 4:10's would be at modern highway speeds. Just screaming down the road lol

From my observations, they usually seem to top out at 60-65MPH. That's what I've seen from driving them.

.(btw awesome you have an IDI running around Boulder)

I think it is too. When I drove mine through there, right past the college, back in 2019, I sure got A LOT of dirty looks. Apparently they didn't appreciate the black smoke from my exhaust at every stop light. Well I wasn't going to turn my fuel down just to make them happy when I was only driving by once!

 

[Cubey]

From my observations, they usually seem to top out at 60-65MPH. That's what I've seen from driving them.

Without turbo, I'm guessing you mean. The turbo RV was up to 75-80 once or twice, where I had to speed up to get around a merging semi or something like that. Can't remember if it was towing anything or not. Stock tires for 3rd gen dually Econolines are 215s.

 

[IDIBRONCO]

Without turbo, I'm guessing you mean.

No. Either way. A turbo will not make the top speed any faster due to torque convertor slippage. 215 tires will make it even slower yet. Plug the numbers into an online calculator and you will find it impossible to go that fast with a 1:1 transmission, 4;10 gears, and 215 tires. Factor in relatively low engine RPM, convertor slippage, and wind resistance due to it being a rolling brick and you'll find out that it just doesn't add up. My first guess is that the gears were no longer 4:10s.

 

[Cubey]

No. Either way. A turbo will not make the top speed any faster due to torque convertor slippage. 215 tires will make it even slower yet. Plug the numbers into an online calculator and you will find it impossible to go that fast with a 1:1 transmission, 4;10 gears, and 215 tires. Factor in relatively low engine RPM, convertor slippage, and wind resistance due to it being a rolling brick and you'll find out that it just doesn't add up. My first guess is that the gears were no longer 4:10s.

The oil looked like it was from 1985 when i changed it in 2019, and it still had the 4.10 tag under a bolt. You'd think someone would have removed the tag if it was changed.

According to this, 3500rpm could get it to 77mph.

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Source: https://spicerparts.com/calculators/transmission-ratio-rpm-calculator

3500 is a little less than mid way in yellow on the F series tach. Econolines never got tachs in 3rd gen, so I had nothing to reference for RPM. Evidently, 6.9s are factory governed to 3800rpm, just before red.

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