I've been ponderin'

[Hedgehog]

Okay this is about swapping one Dana 30 front end for another........

The candidates are

1 - the Dana 30 on my '75 Jeep, it has drum brakes, an open differential running 3.73 gears, new bearings all around and a nice set of brand new Warn Delux Hubs

2 - A Dana 30 from a '76, it has disk brakes, an open differential running 3.54 gears, the hubs, well at least one hub is cracked.

Oh why oh why would I want to swap?

First off I'm a Jeeper and can't leave well enough alone, then the discussion gets more serious.

Brakes:

My '75 has drum brakes, but to be honest I'm not all that sure what is so great about disk brakes. Don't worry about preaching the virtues of disks, I've had'em for years. Honestly I was all set to change the drums out until I actually drove my Jeep and found the drums weren't all that bad, to be honest they are far better than expected. So swapping simply for the brakes change over is iffy at best.

Then there is the gearing:

Most would prefer the 3.73's to the 3.54's. I understand their reasoning, but I'm going to try to face my deamons straight on. Most of my driving will be on an interstate to a place I want to hunt. I've been driving the '75 for about a 2 months now and have documented every mile. I've gotten a low of ~8.5 and a high of 12.6 MPG. I don't know where the 12.6 came from, but it apears that 10.5 MPG will be about average. I want higher mileage, no I'm not crazy, I'd just like "some" more miles per tank full. The 3.54's are tempting for several reasons. They are already at home in their Dana 30 so I would save on install costs. The Dana 30 carrier is already the small one so if needed 3.31 and higher gears will fit without worrying about a new carrier. The '76 would cost ~$300 complete. The labor for Installing a different carrier and gear set would be far more than that, then when you factor in the front brakes. All in all it seems like a good idea, but I have a brand new drum master cylinder and preportioning valve that would be trashed.

I'm interested to see your thoughts on the matter.

 

[ThisGuyUKnow]

Okay this is about swapping one Dana 30 front end for another........

The candidates are

1 - the Dana 30 on my '75 Jeep, it has drum brakes, an open differential running 3.73 gears, new bearings all around and a nice set of brand new Warn Delux Hubs

2 - A Dana 30 from a '76, it has disk brakes, an open differential running 3.54 gears, the hubs, well at least one hub is cracked.

Oh why oh why would I want to swap?

First off I'm a Jeeper and can't leave well enough alone, then the discussion gets more serious.

Brakes:

My '75 has drum brakes, but to be honest I'm not all that sure what is so great about disk brakes. Don't worry about preaching the virtues of disks, I've had'em for years. Honestly I was all set to change the drums out until I actually drove my Jeep and found the drums weren't all that bad, to be honest they are far better than expected. So swapping simply for the brakes change over is iffy at best.

Then there is the gearing:

Most would prefer the 3.73's to the 3.54's. I understand their reasoning, but I'm going to try to face my deamons straight on. Most of my driving will be on an interstate to a place I want to hunt. I've been driving the '75 for about a 2 months now and have documented every mile. I've gotten a low of ~8.5 and a high of 12.6 MPG. I don't know where the 12.6 came from, but it apears that 10.5 MPG will be about average. I want higher mileage, no I'm not crazy, I'd just like "some" more miles per tank full. The 3.54's are tempting for several reasons. They are already at home in their Dana 30 so I would save on install costs. The Dana 30 carrier is already the small one so if needed 3.31 and higher gears will fit without worrying about a new carrier. The '76 would cost ~$300 complete. The labor for Installing a different carrier and gear set would be far more than that, then when you factor in the front brakes. All in all it seems like a good idea, but I have a brand new drum master cylinder and preportioning valve that would be trashed.

I'm interested to see your thoughts on the matter.

What tire size?

 

[Hedgehog]

31x10.5x15 - I've been over this before, I want a vehicle that will get me down the highway. So, back figuring actual tire size which would be 28.5" the calculators with the geas I have now (3.73) the engine is turning at 2854 rpm @ 65 which is accurate. With the 3.54 gears the engine will be turning 2713 @ 65. Not a big difference. With 3.31's it will be 2537 @ 65. Much closer to what I'm shooting for but the advantage to changing would be the smaller carrier. The 3.73's and up require the bigger carrier, @ 3.54 the smaller carrier is used.

Remember, this is a desert Jeep, we don't get much mud or other obsticles you see a lot of back east. I can grind along just fine with 3.54 gears.

Edit: I just found another front end for ~100. I would take some traveling to get it, but whats a few hundred miles here in Arizona.

 

[007]

I don't blame you a bit. I just went to 2.72's for the same reason, and low range will take me wherever I plan on going anyway (just as your low range will).

If I was building a crawler that would be different, and it would probably be on a trailer anyway so it would matter even less.

I think there's a lot of folks that think of gear ratios like notches on a bedpost. For me, the reality is that the vast majority of my driving will be on blacktop whether I like it or not and my low-range will handle the rest.

 

[caveman]

I would leave it alone. First off, You say you're happy with the drum brakes. Altho disc brakes are better, I don't find them better enough to change it out. You could also just change the outers if you realy wanted them.
Second. If you change the gear ratio in the front, You'll have to change the rear too. Another $300 plus extras. Who knows.
Third. I don't think that you'll find much diference in gas mileage between the two. Maybe a little but not enough to justify the cost. If thats what you're going for, You need to go up to 3.07s or so. With the 31 inch tires it would be like having an Overdrive .

 

[SlowPocono]

I would leave it alone. First off, You say you're happy with the drum brakes. Altho disc brakes are better, I don't find them better enough to change it out. You could also just change the outers if you realy wanted them.
Second. If you change the gear ratio in the front, You'll have to change the rear too. Another $300 plus extras. Who knows.
Third. I don't think that you'll find much diference in gas mileage between the two. Maybe a little but not enough to justify the cost. If thats what you're going for, You need to go up to 3.07s or so. With the 31 inch tires it would be like having an Overdrive .

That makes sense to me.

If you really want long legs for the highway, an Overdrive is the way to go.

Why not get one?

 

[Hedgehog]

The over drive option has shown some interest in my brain. I worry about a couple things though. A CJ5 has NO room to spare and the drive shaft is already short enough. Then there is a considerable expense involved. I'm going to do some research today on over drives. I do know that the T-20 can't be retrofitted with an OD like a T-18 can. To get an over drive in my application it needs to go between the engine and the Transmission .

I know the rear will need to be done, but the carrier in my Dana 44 is already the small one and I have access to gears and a guy that will help me every step of the way. My Jeep guy is confident in my ability to get the job done.

 

[Hedgehog]

I cant find anything on the Over drive I was talking about. They did exist we were talking about them that last time I was in Willys Works.

 

[ThisGuyUKnow]

Does the Dana 20 have a different spline and bolt pattern than the Dana 300 ?

Just looked up info on Novak and found the answer. I don't think those overdrives are very cheap. You may end up spending more in conversion than you'd save in gas.

 

[Hedgehog]

There is a big difference between the 300 and the 20. But the 300 is a great Transfer Case , if there is an option there some place I'd consider it.

I'm not one to stray to far from what came in a Jeep from the factory, but I'm not big on sticking an over drive in. the Jeep transmissions with over driver were weak.

In a perfect world my setup would something like, going backwards from the axles to the engine:

- 10.5x31x15 tires, I like'em, they are easy to find and will do everything I ask

- 2.73 gears, yes tall gears for the road

- A Dana 20 or D-18 Transfer Case with terra low gears in it, twin sticks with the pills in place. If I need it this will give me a nice low crawl.

Guy - I am old enough to know that my fuel savings will likely never overcome the cost of modifications. Fuel savings is one of those things that make me feel better at the pump. But you need to consider the driving conditions we have out here in the west, sometimes its a VERY long ways between gas stations, even then they might not be open. Yes, I will be carrying extra gas and eventually one of those 21 gallon gas tanks will be part of my Jeep. In my '80 there were many occasions where I did not know if I'd be getting home. But I was younger then and could simply brush off the fear and keep on going. Honestly, I never did run out of gas, but on a few occasions I did turn around for fear of it.

- A T-18 Transmission with the low or compound first gear, either the Jeep or the Ford would do nicely. I liked the one I put in my '80 CJ5 and I lust for another one. With the T-18 the first gear can easily over come most any difficulties associated with tall differential gearing.

- A rock solid clutch like one of the three finger center force models. Generally I have no problems with a clutch, but while we are dreaming why not a great clutch.

- Hydraulic clutch mechanism, these over come many clutch linkage problems with a CJ frame

- My 360 with fuel injection, I'm not particular, I'd like one with an EPA certification. I like my 360, but fuel injection has proven itself to be superior in everyway. With that being said, my 2150 carb hasn't given me any problems.

 

[Petescj]

Ive got 2.73s in the Limited project. Id swap them for your 3.73s. I'll need the larger carriers for 4.56s.

 

[Petescj]

Ive got a Dana 30 and AMC20 . You have a Dana 44 rear dont you?

 

[Hedgehog]

Yes I've got a 44 in the rear. The journey to my perfect Jeep will be a long one and may never actually get there. For the 2.73s to work I'd need to have all the other pieces ready to go and that's beyond me right now.

With that being said swapping out the Dana 30 I've got now with the one I've been looking at would get me a step or two in the right direction. At that point I would have the proper carrier for your project. I can't make promises, but won't forget your need.

 

[mtnwhlr]

I don't think you will ever be happy with what you have. That said some one like you is always going to try and improve in what you have because you will always think you can make it better. And I'm not saying this is a bad thing just how I see it.

 

[Hedgehog]

mtnwhlr - I'm not sure where you came up with that. You might be surprised at how happy I can be. Right now all I want is a little better mileage and can't break the bank to find it. The Jeep was a pile of junk when I got it and nothing was replaced that didn't need replacing. I don't go all wild about suspension, I don't go crazy about the latest of anything. This Axle swap more than likely isn't going to happen, some would do it just for the disk brakes, in reality I don't have a problem with the stock drums. So, I don't follow the newest trends, and waste money on what is popular today. I need to stop, I know you meant no harm, in a way I suppose you are more right than I'm comfortable with.

 

[Hedgehog]

After sleeping on it there is little doubt in my mind that what I'm doing is somewhat rebuilding my past. My '80 had front disk brakes, 2.73 gears, a Dana 300 Transfer Case , a T-18 Ford truck Transmission and a V6 Buick engine. Before the Buick I had a GM 151 Iron Duke and SR4 Transmission which were an epic fail, st least by most peoples experiences. Granted the 231 V6 isn't the same as the 360 I've got now, but the simple old Dauntless Buick 225 V6 is getting hard to find. There were many happy hours spent in the '80 CJ5 , so I'm sorry but I can be satisfied ....... somewhat anyways.

 

[007]

After sleeping on it there is little doubt in my mind that what I'm doing is somewhat rebuilding my past.

HA!!! That's the ONLY reason I don't have a TJ Rubicon!

If my dear departed father didn't buy a brand-spanking-new orange/spice 79 CJ7 in the fall of 78 or spring of 79 - I wouldn't have felt the eternal desire for and fallen in love with my !@#$ing CJ with all it's !@#$ing baggage and !@#$ing needs!

Seriously - who else buys a vehicle with so much glee - KNOWING it probably needs:

• Bodywork
• Engine work
• Drivetrain work
• Interior work
• Tires
• Brakes
• Cooling system work
• Ignition work
• Electrical work
• Suspension work

That said - it's YOUR Jeep. You want 2.73's? Get them (I did). You can build an AMC20 to do everything you're gonna do with it. You want whatever else your old Jeep had? It's you're Jeep to do it with. Hell I have my dad's old John Deere 820 and his 80 GMC 1500 with the 5.7 Diesel for the same or similar reasons.

 

[Hedgehog]

I really have no desire to change out my Transfer Case , it works well. I have heard that the low range in the 300 is geared a bit lower than the stock Dana 20 .

 

[Kane]

You do realize that you can just swap the knuckle with the brakes to the other axle right?

 

[Saddle Tramp]

Time to jump in as these are ideas I have been kicking around. I’m tired of getting into top gear (T-18 ) at 35 mph and having to scream down the freeway just to try and keep up with traffic; like looking for a gear that’s not there. I’m not sure replacing my 4.56s with 2.73 gears is as tall as I want to go but I am interested in how well it works.