Rear end change

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Feb 9, 2021 | 08:06 PM

Indybeer

Thread Starter

Laughing Gas

Joined: May 2010

Posts: 1,125

Likes: 191

From: Wharton, PA

Rear end change

I am planning on taking the truck to the Grand Nationals in Pigeon Forge this year. Was planning on hauling it down there, like I did to Truckstock, but the wife surprised me and said she wanted to actually drive there. So have been looking at what needs to be done to get it ready. One thing I am looking at is to change out the gearing in my rear end. My Dana 44 has the original 3.92 gear. It works great for normal everyday driving aroud here on two lanes, but getting it out on the interstate with only a 3 speed, I can get it to 60, but the engine is wound out and I wouldn't want to drive it 9 hrs like that. To get it lower I would have to change out the carrier. I have never rebuilt a rear end. Is this something that I can do without alot of specialized tooling? I am looking at either a 3.73 or 3.54 gear. Not a big change but I really think it will give me what I need to run interstate speeds without pushing the engine so hard.

Yes, No, Genius, Insanity? Your thoughts are welcome.

Feb 9, 2021 | 08:24 PM

ALBUQ F-1

Fleet Owner

Joined: Jul 2004

Posts: 27,301

Likes: 1,059

From: NM

The cost is the same for 3.54 and 3.73, both need new carriers. 3.73 is a great ratio if hills are common at medium speeds, but 3.54 is where I'd be looking if I were on the flatlands. I have a 9" with 3.50 and it does well on the interstates, but I don't usually go above 60 -62. Got to remember, you still have stock brakes and steering.

Have you measured your tire diameters?

Feb 9, 2021 | 09:10 PM

fordf348

Laughing Gas

Joined: Jan 2011

Posts: 1,231

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From: near Philadelphia Pa

Whats the rush Indy, I have the original 4:86 and try to stay below 50 and just enjoy the ride
Ed
near Philadelphia

Feb 9, 2021 | 10:16 PM

Indybeer

Thread Starter

Laughing Gas

Joined: May 2010

Posts: 1,125

Likes: 191

From: Wharton, PA

Not so stock...I have front disc brakes and power steering now. Main issue...is this something that I can do myself fairly easily without buying special tools that I would rarely use?

Feb 9, 2021 | 10:52 PM

52 USCG Panel

Logistics Pro

Joined: Oct 2014

Posts: 3,914

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From: Deerbrook, WI

Hi Mark. I have the same gear ratio as you--3.92--and I'm not so sure I'd be happy if it were any lower. Most 90 degree turns at non-controlled intersections I can make without downshifting--but just barely. I think that ability is more important than a little more speed on the highway. Downshifting on hills is another thing I like to avoid. If my truck is running right, I can make it up all but the very longest steepest grades in high gear.

On interstate highways, I usually cruise at about 60- 62 mph. Going 65 starts to feel a little fast, but sometimes I push a little maybe up to 68 or so. Going into the low 70's is possible but doesn't feel safe or something the engine should be expected to maintain. My tires are 16X6:50 with a diameter just shy of 30 inches.

Good luck on your adventure! Planning and strategizing is all part of the fun.

Jim

Feb 9, 2021 | 11:43 PM

ALBUQ F-1

Fleet Owner

Joined: Jul 2004

Posts: 27,301

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From: NM

Quote:

Originally Posted by Indybeer

... Main issue...is this something that I can do myself fairly easily without buying special tools that I would rarely use?

To do it right, you really need a fair amount of specialty tools; dial indicators mostly. Check out 3Twinridges' rebuild of his D44 to 3.54 gears, it's in his "Dallas" build thread I think.

Feb 10, 2021 | 07:21 AM

hooler1

Fleet Mechanic

Joined: Sep 2010

Posts: 1,837

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From: Mason City, Iowa

I have a Dana 60 in mine, which has 3:54 gears, and a recently rebuilt FMX automatic transmission. In 3rd gear which is 1 to 1 I can easily drive 65 MPH at a hair over 3000 RPM. I was thinking about trying to go a little higher gear by changing rear ends because my exhaust was too loud at 65 MPH/3000 RPM. You couldn't carry out a conversation in the cab, much less listen to the radio. Ended up having a shop change out the old cherry bombs with just a set of normal mufflers. It may not sound as cool anymore, but its much, much quieter inside the cab now and is a lot more pleasurable to drive on the interstate.