5-speed trans for '72 bullnose

Does anyone know if there is a 5-speed OD manual transmission that can be adapted behind the 3.8 l for a '72 Commando?

 

Nothing that just bolts in.

You could use a T-5 from a later CJ-5, but you'd need to change to the Dana 300 transfer case that goes with it. An AX-15 with a D300 is another possibility http://www.novak-adapt.com/knowledge/transmission_gateway.htm Both the AX-15 and the T-5 will bolt up to the 232. The T-5 isn't renowned for durability in Jeeps, but it might be ok behind a 232 if you don't abuse it - IMO the AX-15 (or NV3550) would be better.

<edit> Just curious - why do you want a 5-speed?

 

I have a 3-speed righ now and I was thinking maybe an OD would save a few pennies in gas. The overdrive might notbe a good option with the 3:73 gears.

 

The OD would be OK with those gears, but are the $$ spent worth the gas savings, plus the down time of your rig. If you spend $2500.00 and get an extra couple mpg it will may take you 150,000 - 300,000 miles to recoup your investment. But if you want better drivability then that's a different plan. I think a Commando with and OD trans would be cool. Look into the Ranger units, which installs between the engine and trans.

 

:iagree:

The mileage you see is mostly because of the aerodynamics, not the engine speed. I predict you will not see any significant mileage increase with either a different axle ratio, an overdrive, or a 5-speed transmission.

People don't realize how steep the wind resistance barrier is. Reduce your speed by 10%, and the wind resistance drops by 19%. Reduce by 20%, and you have 43% less wind resistance. You can likely get an immediate increase of at least 10% in mpg by lowering your top speed by 10 mph. Lift, big tires, higher speed are all working against you ... the transmission is not the problem.

Before I'd make a transmission swap, I'd make an engine swap to a Jeep 4.0L with the Mopar multiport fuel injection. Then you'll have more power and better mileage. Lots of people have made this swap - complete parts cars are widely available and there's even a web forum specifically for this swap. http://www.cjoffroad.com/forums/forum.asp?FORUM_ID=24

 

what about using the world class t-5's not the regular jeep/ford t-5's,,,the ones that came in the 5.0 stangs and v8 camaros,,,

 

Apparently it can be done, but there's no public domain info on how to do it that I know of. 5speeds.com used to sell the T5WC ready to install in Jeeps, but no longer. http://www.5speeds.com/t5/jeep.html Wasn't cheap - ca $1500 outright IIRC. If you were really interested, you could call them - maybe they'd build one for you.

 

I had a friend of mine that swapped out his T5 to a WCT5 about 3-4 years ago thinking it would be better. With a 350 small block and 33" tires it lasted about 3 months of wheeling. The big thing in twith Jeeps compared to cars is driveshafts and tire size, the gears in the world class T5 just are not big enough to handle the mass of 33" tires spinning and since the jeep driveshaft has no length for flex something has to give, its usually the light weight transmission.

 

I just received the title for my new prize so my first order of business is to get on the road with some degree of safety. First on the agenda will be to get more than one brake working. Front reservoir was bone dry and the rear one had about a teaspoon of fluid in it.

Then i need to get the electrical working. the right turn signal blinks very slowly and the wipers run about as slow as the blinker. Absolutely nothing else works.

Fraid the transmission will have to wait a while.

 

Sounds like a good plan, keep us updated.

 

I too have considered a 5 spd - for driveability. I am a recent Jeepster guy (38 years and counting with a '47 wagon) and find the non-syncro 1st to be less than ideal. I do not yet know my differential ratio, but the gears seem pretty tall. The rig will happily roll along at 40 in second, but does not like pulling from under 10-15 in second. Any suggestions for improving things short of a major transplant? I have a stock '67 convertable rolling on stock wheels/tires pulled by the 225. It is a road only car; no real off road is contemplated.

patrick

 

It's ok to start a new thread about this.

Look at the cover bolts on the axles for a tag with the gear ratio.

I'm not sure what you mean by 'major transplant' - about the only easy route is another Borg-Warner 3-speed, or the Tremac T-150. Both of these are stronger than the T-14 (or T-86?). If you have the T-14 currently, only the second gear ratio will change much, and not in the direction that you want.

One possibility would be the T-176 from an '80 or later 6-cylinder CJ-5 or CJ-7. That would give you roughly a 4:1 1st gear (v. about 3:1 now), and spread the ratios a bit better. The other possibility might be a different set of axles from a CJ of about the same vintage. This would be an especially good swap if you have the Dana 30 rear axle.