Topic: Dual cases or 4.7's with a lot of freeway driving?

[Erich in Az]

Hello,
   I was hoping to get some advice from you guys. I am currently debating on going with your 4.7:1 case gears or MC07 dual case adapter and it's driving me silly. The vehicle is an 87 4Runner (currently IFS, but going to SAS) with a 22re, 4.88's and 33's. What is posing the biggest problem for me is the fact that I drive the truck 124 miles a day to and from work. It's pretty much all freeway at high speeds.

My concerns are:

• Reliability - Will the dual adapter stand up well to 30k miles a year at high speeds?
• Economy - Will I end up losing a noticable amount of gas mileage due to the extra drag of the 2nd case internals? I'm already throwing $13 a day in the tank

  Things I like about the dual cases are the 2.28 low still available, and the 2low range I get. I already have a case (2 actually) and with the SAS, it's getting a front driveshaft. Losing my console will be a bummer though.

In your opinion, would I be better off doing the gears, or dual cases in my position?

Thanks,
Erich
 

[GRM]

Dual cases are nicer, because of more gear choices. BUt they do eat up gas milage. I run 4.7's just because they are that much cheaper.

I honestly dont know how much mpg you'll loose, but I am assuming it is in the 3 mpg range.

and $13 a day isnt bad. I used to spend about $20-30 a day.

[Hyena]

I have dual cases and i love them.  Crawl slower with cases rather then gears.  I don't think it is that much different on the road.  I had a death rattle right after i put them in but it all of a suddon went away.     My oppion is dual cases.

[brainlessfool]

well I can't see how duel cases would make any diff. in on the MPG that you would notice. In high it just runes straight though. just three extra bearings truning. thats all I belive.

[yotaboy79]

if you can aford it go with duels if not go with gears if you cant aford eather like me your outa luck like me     

[BLUCRUZ]

I run dual with 4.0 & stock and drive over 60 miles a day. i get around 15mpg. I go through u-joints in the rear about every 6 months due to my driveline angle. Thats the only drawback i can see.

[Erich in Az [OP]]

well I can't see how duel cases would make any diff. in on the MPG that you would notice. In high it just runes straight though. just three extra bearings truning. thats all I belive.

It's the bearings, plus the whole shaft that has to turn. Turn the input shaft of a case, even in 2 high and see how much drag is created. That's my concern.

I run dual with 4.0 & stock and drive over 60 miles a day. i get around 15mpg. I go through u-joints in the rear about every 6 months due to my driveline angle. Thats the only drawback i can see.

That's about 5-6mpg less than I'm getting  At current gas prices, that ends up being roughly $82 a month more in gas or almost a $1000 a year. If that difference is mostly in the drag of the other case, that kind of makes up my mind.

The upfront cost of either is pretty much the same as I have other top shift cases laying around and doing the driveshaft is not that big of a deal, but the more I think about, the more it seems that mileage will suffer, and that adds up for me BIG time. With this in mind, I think I will go ahead with the 4.7's. I can always add a dual case next month. I was hoping to hear from the Marlin folks here and see what their experience has been with all the ones they have put out.

Thanks for everyones input on the matter.

[kyle_22r]

i'll probably just go the single case with 4.7s route here.  if i need a higher low range i'll just put it in 3rd gear 

[KYOTA]

I'm running duals with 4.7 and 2.28, and have been driving it to work 120 miles a day, figured my mileage tonight when I filled up and I'm getting 18mpg

[87Fontana]

Is anyone runny duals with 2:28's in both cases?  It seems putting both cases in low would be nearly equivalent to one case with 4:70.  I had a single case in my old 4Runner with 4:70 gears and I cannot image needing anything lower.  The only thing that sucked was not having the stock 2:28 range for normal stuff.

[Goldrush]

Highway driving you will be good to go. There are plenty of ppl DD there dual cased trucks.  Dual 2.28 is actually slower than 4.70x2.28 or single 4.70.


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[Nation]

I really felt like my 2.28x4.70 was much lower than my dual 2.28s..  i have seen 100 mph with duals. No issues. Drove from LA to Rubicon trail. 10 hours each way. 80 mph entire time. No issues.

[BigMike]

Is anyone runny duals with 2:28's in both cases?

In my guestimation, the breakdown on our customers are as follows:
40% run a single 4.70 case (because it's cheapest and easiest to install, get your foot in the door of Rock Crawling, already lower than what most Jeeps can only dream of achieving)
30% run dual stock 2.28 cases (because someone told them it's better and the additional cost and effort was not a factor)
25% run dual Ultimate cases (these are the customers who really take Rock Crawling serious)
<5% run some configuration of triple cases or a type of Overkill setup (genuine or 'wanna-be' -- more info)

It seems putting both cases in low would be nearly equivalent to one case with 4:70.

You are correct that a Dual stock case is nearly equivalent to one 4.70:1 case, however your sentence structure seems to have the wrong emphasis: Dual stock cases are actually 10.9% lower than a single 4.70:1 t/case (2.28 * 2.28 = 5.19). Marlin invented the 4.70:1 ratio in 1995 as a complement to his Dual Case setup and not the other way around.

The only thing that sucked was not having the stock 2:28 range for normal stuff.

This is the leading reason to start with dual stock cases instead of one single 4.70:1 case.

To answer the OP, I daily drove my Triple Marlin Crawler setup (2.28 + 2.28 + 4.70) from 2004 to 2010, averaging over 16,000 miles/year and still to this day I have both never experienced any issues nor opened up my cases for inspection. My Marlin Crawler parts have not seen sunlight for a decade and are still going strong. As for gas mileage with a dual case, the only difference will be the increased drag of three gears rotating in gear oil and an additional 40 pounds drive train weight, not including a larger and optional dual case cross member. For my mileage, I have a 1995 2.7-liter 4cyl T100 3RZ-FE in my 1981 Hilux with 37" tires on 5.29:1 diff gearing and I get 21 MPG at 65 MPH or 19 MPG at 75 MPH with a Triple Crawler (twice the weight and parasitic loss as dual cases).

Single or Dual Case setup? I wouldn't have it any other way than Dual. Click here (reply #7) to see my comprehensive Pros/Cons of each setup.

Regards,
BigMike