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Pinion gear swap 2.73 to 3.54

Chipster1990

Chipster1990

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I’m sure this is buried in a thread somewhere, but I can’t find it.

I currently have Dana 30/AMC 20 stock wide track with 2.73 gear ratios. I want to swap them to 3.54. Do I have to swap the carrier to go to that ratio?

Thanks in advance!
 
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www.drivetrainamerica.com

Carrier Breaks for Differentials Explained

Defining Differential Carrier BreaksDifferential carriers are designed to accommodate a wide number of gear ratios for the various tire sizes and vehicle applications associated to them. As the numerical ratio of a gear set increases, the diameter of the pinion gear gets smaller. The reduced...
www.drivetrainamerica.com www.drivetrainamerica.com

Looks like not for the Dana 30, but you do for the AMC 20.
 
Bad news for me, but very helpful. Thanks for the info and the link!!

Anyone have an AMC 20 wide-track that’s 3.08 or higher in number that they want to get rid of?
 
wm69 said:
Just get you a Detroit Truetrac. It replaces the carrier, so you get a good LSD and don't have to shop for another carrier
Click to expand...
I want to stay as close to AMC original as possible. Is the Detroit pretty much a bolt in replacement?
 
The truetrac is an all gear limited slip carrier. The factory carrier was either open or limited slip with clutches. The truetrac is a replacement for the factory carrier so you can use numerically higher gears with your original axle assembly. Of course you will have to take the entire thing apart and properly set up the gears in order to make the change.
 
sdsupilot said:
The truetrac is an all gear limited slip carrier. The factory carrier was either open or limited slip with clutches. The truetrac is a replacement for the factory carrier so you can use numerically higher gears with your original axle assembly. Of course you will have to take the entire thing apart and properly set up the gears in order to make the change.
Click to expand...
Yep, but he'll have to do that with a new carrier and gears too.

The factory limited slip (track lok) used clutches, which tend to wear out and not work anymore. They also didn't split power between the rear wheels very well other than when they were brand new. Thus the nickname "trash lock"

The other option was open, which gives you one wheel spinning and the other sitting still.

A truetrac is gear driven, so it doesn't wear out like clutch operated limited slips. It isn't a locker so it will not be rude on the pavement with chirping tires and ratcheting in corners. If one wheel spins, it will transfer power to the other wheel.

They aren't cheap, but if you're already having to buy a new carrier the price difference won't be as much, and they are a tremendous upgrade for a CJ, even if you're not off roading it.

 
If you decide to stick to stock, look up Dawn and Jody Abbot. They're over NW of Atlanta so would be within driving distance for you.
 
wm69 said:
Yep, but he'll have to do that with a new carrier and gears too.

The factory limited slip (track lok) used clutches, which tend to wear out and not work anymore. They also didn't split power between the rear wheels very well other than when they were brand new. Thus the nickname "trash lock"

The other option was open, which gives you one wheel spinning and the other sitting still.

A truetrac is gear driven, so it doesn't wear out like clutch operated limited slips. It isn't a locker so it will not be rude on the pavement with chirping tires and ratcheting in corners. If one wheel spins, it will transfer power to the other wheel.

They aren't cheap, but if you're already having to buy a new carrier the price difference won't be as much, and they are a tremendous upgrade for a CJ, even if you're not off roading it.
Click to expand...
100% agree. The truetrac would be my choice in that position. I had a track lok from the factory in mine. It was pretty sad.
 
wm69 said:
Yep, but he'll have to do that with a new carrier and gears too.

The factory limited slip (track lok) used clutches, which tend to wear out and not work anymore. They also didn't split power between the rear wheels very well other than when they were brand new. Thus the nickname "trash lock"

The other option was open, which gives you one wheel spinning and the other sitting still.

A truetrac is gear driven, so it doesn't wear out like clutch operated limited slips. It isn't a locker so it will not be rude on the pavement with chirping tires and ratcheting in corners. If one wheel spins, it will transfer power to the other wheel.

They aren't cheap, but if you're already having to buy a new carrier the price difference won't be as much, and they are a tremendous upgrade for a CJ, even if you're not off roading it.

Click to expand...
is there any place where I can buy the Detroit truetrac already assembled with the pinion gears?
 
Chipster1990 said:
is there any place where I can buy the Detroit truetrac already assembled with the pinion gears?
Click to expand...
It wouldn’t come that way. The new ring and pinion will need to be set up properly in your housing.
 
If you're regearing at all you always have to have the new gearset set up by someone who knows what they're doing.

There are shims that are used to position the carrier/ring gear and pinion gear so that they mate up with one another perfectly for smooth quiet service. If the ring and pinion gear aren't properly set up, your gears will eat themselves and grenade the rear end.

And every housing/ carrier is slightly different so there isn't any "ready to go" possible. The ring and pinion have to be set up custom every time gears are swapped.
 
FYI, you'll have to have your front gears set up as well. Even though the carrier for the ring gear can be used, the gears themselves will have to be set up.

The only way around it is to buy complete axle assemblies with the gears you want already installed/ set up. You might be able to find some 3.31 factory widetracs cheaper than you can regear your existing axles. 3.54 widetracs would be a bit on the rare side.

Keep in mind buying used complete axle assemblies opens a whole new can of worms with "do the next assemblies need any work/parts"
 
Thanks for all the information. I have a much better picture of this process now. I will have a qualified individual do the re-gearing and proper set up. Thanks so much!!
 
Anyone recommend a shop in AL, TN, GA area that could perform the re-gear and Detroit install?
 
Not to open a whole can of worms... I would also price a complete bolt in Dana 44 from east coast gear supply. You should be able to get something bolt in ready that is all new for under 4K.

Also, make sure when pricing to let them know you want a "Detroit true trac". Eaton also makes a "Detroit locker" that is an automatic locker. The Detroit locker has less desirable street manners than its limited slip sibling.
 
I can find people around here, not shops, that would do that for $300.
 
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