What exactly do I have here? ::BIG pics::

Please help. :? Pictures included.

I know i've got a L-134, and it looks like a T90, but i'm unsure about my transfere case. Is there an overdrive hidden in there?

 

standard Dana 18 twin stick. No OD. The OD would be external coming out of that plate off the back of the t-case inline with the tranny.

 

Yea, i finally found pics of one. :\ Is it worth getting one or better to save and do an engine swap?

 

What do you plan on doing with the Jeep? Personally even with an engine swap I would do an OD because you 99% chance have 5.38 gears in the axles and at highway speeds your revs are what are going to limit you more then your power. Anyway that 4th stick coming through the floor is just so cool

 

Kinda looking into using it for roadtrips and wheeling. I'm gonna just put on some 235x75x15 mud terrain tires, perhaps swap in a 225 buick, and maybe an overdrive, and use it to drive around.

 

If I understand correctly, I think an OD will also allow you to have extra gears too. Like if you're in 1st gear, low range, you can engage the OD and have a gear that's between 1st and 2nd. Then disengage the OD and shift to 2nd, and so on. Kinda like...
1st
1st and-a-half
2nd
2nd and-a-half
3rd
3rd and-a-half

So, between low range and high range, with OD and without, I think you could actually have up to 12 separate gears? And if you remove that "detent pill" in the tcase, you can do all this in 2wd also? Not that you'd want to do all that dinking around on the road, but the ability might be handy off-road sometime.

That's how I understand it, but I might be on crack too.

 

Yes, it's a true splitter, in that you'll have all your original gears, plus those gears with their ratios multiplied by 0.75. So if you have a 5.38:1 final drive ratio, you'll have a 4.035:1 final drive ratio with the overdrive engaged. It's probably easiest to think of it as giving you two axle ratios; I don't think that users split the gears that much in everyday usage.

Unless you want to putt-putt around town and on local trails, or tow your Jeep to the trail, you probably want an overdrive and a larger engine. The 5.38:1 gearing makes the RPMs high at cruising speed, but even if you have the overdrive, you'll be power limited (wind resistance!) at much above 45 or 50 mph.

Modern 4-cylinders are another good swap candidate, but the Jeep/Buick V6 is very popular for good reason.

 

while this is certainly possible, your arm won't last long if you try it in traffic. what it will do is allow you to find just the right ratio for the situation: second is just a bit low for toolin around the neighborhood, but 3d is a tad too high...etc

 

I have watched Randy try the whole gear splitting thing. Yeh it does not look like much fun. But in theory you could do it if you liked shifting that much.

 

T90 and Model 18 are std Military
1 1/8" pin Doug

 

what exactly is over drive? it sounds cool-would it help speed on the highway?

 

So my Jeep is an MB?

 

With 4.88 gears, I use 2/OD a lot when I'm in town.
I use 1/OD in low range sometimes.
3/OD on the highway, of course.

 

That's exactly what it's for! Gives you a little higher gearing on the final drive. It's an add-on unit that attaches to the transfer case. I believe it changes the drive ratio between the transmission and tcase.

In other words, you're wailing along in 3rd gear at a blinding 50mph, then shift into OD and you can go a little faster, or maintain the same speed with lower RPM's on the engine.

 

Adding a little more technical description to Rondog's reply, it's a 2-speed (1.0 & 0.75) planetary transmission that bolts to the back of your transfer case at the PTO port, that access cover behind and inline with your transmission.

Adding an OD to a L134 or F134 Jeep will increase your top speed a little, but at those speeds you're mostly power limited (wind resistance!) so don't expect a magic transformation into a freeway flyer.

Great product otherwise - highly recommended. Cost effective too - if you sell, you can resell the overdrive separately or it will increase the value of your Jeep about as much as it costs.

 

Nope. Civi Jeeps ran the same drivetrain. So just because the stuff is there does not make it a military Jeep.

 

It couldn't be much different then the 8 speed unsynchronized tranny in our freightliner, playing with the splitter in that is fun too R)

 

so where can i get an overdrive?

 

www.hermtheoverdriveguy.com

 

Yours doesn't look bad outside. I would clean it up an pull the tower to check the inside.