Anyone gone the Gear Vendor Overdrive route rather than a 4L80 swap ?

[JoeJrTheBarber]

Question:

Looking to do something about the stock 3 speed in my 1988 Humvee and its looking to be either a 4L80E swap or a Gear Vendor under / overdrive unit. Coming from the hot rod world I have experience with both setups but I haven't heard (not can find anyone) that has added a Gear Vendor to their Humvee. Is their a reason for this ? I am willing to loose alittle "off road-ness" to be able to cruise at 70-75 without the truck shaking apart and enjoy driving the truck allot more..

Anyone ?

 

[Dock Rocker]

I would think it would be mighty close quarters and leave you with a really short driveshaft.


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[cruzinz28]

I have been pondering this concept myself. With what little research I have been able to do so far I don't think gear vendors makes a direct bolt up package. I believe someone over at G503 contacted them directly and that was what he was told.

Now, there was a Slant Back for sale over on the same site from a Canadian member that was able to adapt the gear vendors overdrive into this truck. I sent him a message last week to see if he had any pictures or information to pass on for how he accomplished this.

As for the rear drive shaft being short. This would be the least of my concern. My father has been running a TH400 in his CJ5 mated to a small block Chevy with a Dana 20 transfer case since 74' which only left room for 12-1/2" drive shaft. In the HMMWV we don't have to worry about drive shaft angle and suspension drop in regards to the rear drive shaft because the Rear is fixed mounted in the independent rear suspension setup. Please, correct me if I am wrong with that last statment.

Now, the part where things get tight is when we look at the muffler and gas tank clearance after we install the underdrive between the transmission and transfercase pushing the transfercase further back. It would appear that there might have to be a muffler change/modification and possible gas tank mods to make this work.

Remember, anything is possible with enough time and money. One gentleman I talked to said that he was going to do the 4L80E transmission swap and just install a manual valve body in the transmission to eliminate the expensive stuff that comes with that swap like the control box, wiring harness, and kick-down shift sensor. Little more work when driving to downshift when you need it, but you get that extra overdrive gear.

 

[Action]

you want to cruise at 70-75? Even if you keep the engine RPMs down, most of the other gear sets will be spinning a lot faster.

 

[drivebymashing]

cruising at 70 would be great. You could actually keep up with some of the other traffic. 75-80 is normal cruising where i live.

 

[Dock Rocker]

One gentleman I talked to said that he was going to do the 4L80E transmission swap and just install a manual valve body in the transmission to eliminate the expensive stuff that comes with that swap like the control box, wiring harness, and kick-down shift sensor. Little more work when driving to downshift when you need it, but you get that extra overdrive gear.

I am certainly not trying to stop you from re inventing the wheel but I think you may have been misled on the complexity of the 80e swap.

There are multiple people of FB and other places that are selling the complete setup minus controller much cheaper than the GV overdrive. Unlike the GV unit this will drop in and all you need is an aftermarket controller and a Throttle position sensor from GM.

I was lucky enough to have a 242 transfer case in my truck already so I didn’t have to buy the whole setup. Here is what I have so far $575 in a crossmember and nos 4 Speed shifter. I have $500 in the 4l80 and converter. I don’t have the total ha full but I have less than a $100 in the TPS from GM. The only thing left is the controller ($525) and lengthening the front prop shaft by 2 inches that will be $200. All in I am under $2000 after hardware and I think i will have to buy a flexplate. That’s less than a gear venders unit plus there isn’t any fab work and guessing.

The controller is two weatherpack connectors plus hot and ground. It is very simple to hook up and easy to tune.

Also there is a guy on FB that just did a swap with a 700r4. A company sells a drop in kit. He had a shop do the instal and was still in under $4k.





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[Action]

cruising at 70 would be great. You could actually keep up with some of the other traffic. 75-80 is normal cruising where i live.

Look for a different vehicle.
Or, get used to folks passing you.

 

[infidel got me]

Putting this 700r4 in this week. Came with everything but fluid. No fab or driveshaft work. I'll keep you posted as to how it went!!!! Yes I'll take pics of the install....

 

[Dock Rocker]

View attachment 716926View attachment 716927View attachment 716928 Putting this 700r4 in this week. Came with everything but fluid. No fab or driveshaft work. I'll keep you posted as to how it went!!!! Yes I'll take pics of the install....

What kind of money for the kit?


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[infidel got me]

$3400- No core charge- included shipping.

 

[86humv]

Sustained 70 or more.....other things will fall apart.
Trucks not made for it.
I like fast....but in auto's made for it.

 

[DCIV]

I called about an extra add on gear, they don’t make anything.

 

[Dock Rocker]

Sustained 70 or more.....other things will fall apart.
Trucks not made for it.
I like fast....but in auto's made for it.

You do realize that there are thousands of them in the road today that have overdrive and do 70 plus with armor?


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[86humv]

You do realize that there are thousands of them in the road today that have overdrive and do 70 plus with armor?


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They...the Military are authorized only 55 mph.
Some GI'S might go over speed, but in normal practice....max 55.
People going 70 and above are asking for trouble.

 

[Dock Rocker]

They...the Military are authorized only 55 mph.
Some GI'S might go over speed, but in normal practice....max 55.
People going 70 and above are asking for trouble.

What specifically would be the problem? Assuming you have the correct transmission gearing for that particular Speed? And you have the proper tires.


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[Action]

What specifically would be the problem? Assuming you have the correct transmission gearing for that particular Speed? And you have the proper tires.


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[doghead]

70 on the highway with a vehicle sold for off road use only...

 

[Dock Rocker]

View attachment 716991

That’s a great picture. Excellent white balance and all, but it doesn’t remotely answer the question.

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[Dock Rocker]

70 on the highway with a vehicle sold for off road use only...

So a red stamp on a piece of paper for liability purposes of the seller / manufacturer determines Speed?

I bet you never operate over the posted speed limit. That’s another arbitrary number on a piece of paper that differs by State. I bet you break that particular rule all the time.

Since you never have anything positive to offer in the hmmwv section, other than a snarky comment and a ban, why don’t you find somewhere else to spread your sunshine.



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[porkysplace]

That’s a great picture. Excellent white balance and all, but it doesn’t remotely answer the question.

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Well , since the military had that tag installed after they paid engineers to design and test the HMMWV , it would seem they determined that was the maximum safe speed.Just as they tested the HMME-1 backhoe and determined the maximum safe speed being 60 mph.

Your argument might show some credibility when you post your engineered and tested design with a engineers stamp on it.