Overdrive Transmission?

I'm running a 225 and would like a 5-speed manual w/ overdrive. Has anybody done this? Any ideas? I know the 225 has the standard BOP bellhousing pattern, so I can pretty much use any GM transmission/transfer case combo, I just don't know it will be too long, or if it can hold up to the 225 (rebuilt to stock specs).

 

5 speed tranny's are typically too long and adapters for the transfer case will be the big issue. Your best bet for better gearing is a warn/saturn/husky overdrive for the transfer case.. http://www.hermtheoverdriveguy.com/


BUBBA

 

Hey I have a '56 and am lookin' for a bit more driveability around town. I've asked all around and it looks like a Warn/Husky is the way to go However, for giggles I picked up the last issue of JP Magazine and they are addressing this very issue. To sell more mags, I think they're gonna stretch the swap out over a few issues but check it out.
They've started with 5 different options for getting an overdrive gear into an early Jeep. The cheapest would be the Warn OD but they even mentioned tryin' to shoehorn an NV4500 into one. I'd pay close attention to this article. If they find a way to get fix the drivetrain angles with the long NV4500 then I'll be on the waiting list. It's a more expensive option but then again, why would you have bought an early Jeep if you didn't want to take out a second mortgage to fix it

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The nv 4500 is a cool tranny but dollars for donuts you would be better off with the SM-420/465 swap with the warn OD.. it is a much shorter combo and you really wind up with an 8 speed of sorts...

BUBBA

 

only old jeeps to fit an NV4500 are a CJ-6 or commando. might also fit willy wagon/truck/jeepster as well, just don't know those models as well.

 

It just seemed to me that nearly $1000 for a warn OD is a bit steep. Are there any problems with just installing a smaller gear ratio in the diffs? Will 1st gear be too low to get rolling? I'm probably not going to be doing any hard off-roading with this thing, so super deep gears are not a neccesity.

 

trust me after adapters $1000 will sound cheap. Spent nearly 2K on adapters for my ford T-18a to my chevy motor and my dana 18.

 

I don't think you could get a good NV4500 for less than that, especially now that New Process is out of business. Add the adapter cost to that, and you're up around $1500 easily.

There's no way you could change out the gears in your existing axles for taller gears for the same price that the overdrive costs, unless you have lots of skill and tools. Changing gears in axles is probably the most difficult and demanding single task that you can choose for your Jeep, considering the skill and tools required. If you could find front/rear axles with ratios you want, you might be able to convert to new axles for less than the cost of an overdrive. However, your labor counts for something (much harder to swap axles or change gears than to add an overdrive), and low gearing is an asset - everybody wants a favorable crawl ratio, and you're decreasing your crawl ratio with taller axle gears. Low gears are good - everybody want sthem.

The Warn overdrive will add about as much value to your Jeep as you pay for it.

Sometimes the conventional wisdom is right.

 

Tim new process never made the NV4500, New Venture did, it was a merger of sorts between Chrysler and GM, since GM always bought New Process transfercases and some transmissions GM bought a large chunk of stock in the company and together they formed New Venture, and New Venture is still in business as almost all Dodge diesels trucks come with an NV5500 transmission and jeep and Dodge still use the transmissions and transfercases for everything.

 

New Venture, New Process... I thought they started off as New Process Gear, then changed the name to New Venture Gear... maybe not. Didn't the same factory make the transfer cases and the transmissions? The story I heard is that GM pulled out of the NVG effort and DC sold the transfer case business and discontinued the transmission building. DC now uses the Getrag transmissions.

Definitely read that New Venture is gone, kaput, no parts and no transmissions. I can find some links if you are interested.

http://www.newventuregear.com/index.html

 

I hear some gent mention a Clarke, spelling?, 5 speed. Anyone know about them?

 

New Venture was bought by Magna in september of 2004, the name was changed back to New process gear, Chrysler still owns 20% of the company until september of 2007 at which time Magna will buy out the remainder of the company, magna purchased GM's interest along with a large chunk of Chryslers. They are still in business!
Jeeps still use the NP/NV transfercases and the buddy of mines new Dodge 6 speed is an NV5600 transmission and he only bought it about 6 weeks ago.

 

Mmm... still in business but not making transmissions, unless what I read was wrong. Transfer cases only. I think your buddy got the last of the breed - there's been a scramble to buy up the last of the service parts.

The new Dodge trucks now come with the heavy Getrag transmission used for medium duty trucks in Europe. Same transmission that Moggies use, AFAIK.

 

More details from the Quad 4x4 site

"Dodge is replacing the NV5600 with a Getrag 6speed. New Venture/MTM lost the contract to supply Daimler-Chrysler with transmissions. New Venture itself was a now dissolved partnership between Daimler-Chrysler and GM. The transmission assembly plant in Muncie, Indiana, is once again part of the GM Powertrain Group. The plant is currently under contract to supply GM with NV4500 and NV3500 transmissions for several more years. The transmission plant is now known as Manual Transmissions of Muncie LLC."

 

Skill and tools are not an issue - I can't imagine that replacing the gears in a jeep diff are much different than most any other open diff. I work at full service garage, so tools are not an issue. I just don't see where are the cost is comming from for the gears...The last I checked the gears plus an istalation kit ran around $200-250 for a GM 8-bolt. Are the jeep diffs more?

I'll send herm and e-mail - I've been to his site before. I like the idea of having an OD over a different gearset, I just want to keep costs down since I won't be using this for any hard offroading.

BTW - What kind of RPMs are people runningwith an OD as oppsed to not? Give whatever speed you cruise at. Thanks

 

You're right - in your case, you could set up the axles for less than the overdrive would cost. Your Jeep wouldn't lose much value if you stayed reasonable with the gearing, say 4.10s or 4.27s. I've found the 4.27s to be fine on the street, even well above legal speeds. I'd guess that you want to be at around 3000 RPM for your top cruising speed. Which engine is this?

<edit> I reread your post above - the 225 will cruise at 3000-3500 all day. There are RPM and crawl ratio calculators lots of places on the web, such as here: http://www.novak-adapt.com/knowledge/gearing.htm

 

I've done some messing around with these calculators and found that I would to go to an awfully low gear in order to match what an OD can do.

I have also noticed that my CJ-5 (probably late 60's model) has two levers besides the tranny shifter - did any of these come with a 2 lever transfer case in a V6?

 

IIRC it's a 0.75 overdrive, say 5.38 * 0.75 = 4.04. Is that what you get?