Re-gearing 83 Scrambler

Srambler83

Legacy Registered User
City
Houston
State
TX
#1
Gents,

Need you help on a few questions. Looking to upgrade my rear and front gearing for Dana 30 and AMC 20. Jeep will be used for both light off road beach, light trails. No rock climbing. Driving 3 days a week and short 4 to 6 hours trips. Have the 258 with T5 w/ overdrive. Going with 33 or 35 max. Want max gearing rather than not enough so going 4.56 gearing. Please your thought and opinion are welcome. So questions are:

1) 1983 Jeep scrambler correct me if I am wrong but WT or NT, Believe I have the WT?

2) Going for one piece front axels what length do I purchase? Front axels are 55.8? and what else do I need to know when regearing with 4:56? Spline?

3)I want a limited slip for both for both Dana 30 and AMC 20. Would like to keep it both lockers the same. Again do not need anything extreme. Most light trails. Trying to stay away from magnetic, electric maybe a lunch box? Mostly street driving. I was thinking a Spartan locker or maybe a Assuie locker. Do I really need a locker in the front Dana 30? By putting a locker upfront is there and issue with drivability or turning radius etc.? Sorry for ALL the questions on this one...lol

Thanks
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#2
Solicited opinions:

1. If nobody has changed anything, you have wide track axles.

2. One piece axles are for the rear. If you need new front axles, just order them for the WT Dana30, and they will fit. What gearing do you have now? You may need a new carrier to accommodate the lower gears.

3. Depending on your budget, I highly recommend Detroit Tru-Track differentials, front and rear. They will replace your old carriers, so just order them according to the gearing you want.

Unsolicited opinions:

1. 33s are a LOT easier to fit than 35s, depending on how involved you want your lift to be. Do you already have a lift?

2. 4.10 gears are more than adequate for 33s, and the type of driving you described. Even with overdrive, 4.56 gears are pretty low for highway driving... unless you go with larger tires.

3. The T5 transmission can only take so much. I think 35" tires are probably too much.

Have fun! :cheers:
 

Spieg

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Aurora
State
CO
#3
Limited Slip is not the same as a locker. I'd be hesitant to install a locker (or even L/S) in the front if you ever use 4-wd on the road (winter driving?). It can affect your steering and turning radius. A selectable locker (be it ARB Air, Eaton E-locker, Ox cable control, etc...) is what I'd suggest for the front for additional traction (it's really nice to be able to run the front diff open when you want to).
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#4
Wide track it is. I currently have the 2.73 gears.
WT Dana30one piece axels.
Going with the 35" a bit beefy. Like the look. So will the 4.56" be better . RPM chart shows 2845 rpm with out overdrive and with 35"so, rpm should be quite lower.
Yeah know eventually I will have to add the AX15 tranny.
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#5
Limited Slip is not the same as a locker. I'd be hesitant to install a locker (or even L/S) in the front if you ever use 4-wd on the road (winter driving?). It can affect your steering and turning radius. A selectable locker (be it ARB Air, Eaton E-locker, Ox cable control, etc...) is what I'd suggest for the front for additional traction (it's really nice to be able to run the front diff open when you want to).
Do I need anything in the front?
no snow down here in Texas.
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#6
What is a Dana 30 one piece axle?

If you're set on 35s, then 4.56 gears are probably a good idea, and will help relieve the stress on the rest of the drive train.

For the kind of driving you're describing, that may turn out to be a great setup!

You probably don't need a locker in the front, but you'll have the whole thing torn apart anyway, and you'll need to replace the carrier anyway, so if you think you might want one, this would be a good time. I still like the Tru-Trac option. :wave:
 
City
Huntsville
State
AL
#7
I regeared my 83 Scrambler when we rebuilt it. I went from 2.73 to 3.54 gears because I didn't want to change the carriers out. As you are looking to go with lockers/Limited slips, that won't be an issue for you. I'm only running a 2.5" lift with 235/75/R15s (about 29" tire) with a 258 and T5. I love the T5. The gearing I have is good for power and gas milage. Before you couldn't hardly get started without slipping the clutch the 2.73's were so bad. I average about 17 mpg and can run 70-75 with no problem and keep the RPMs around 2200-2300. A little higher gearing would be good going with 33's. Not sure if 4.11 or 4.56 would be best. My TJ only has the 4 banger and I put 4.88s in it rather than 4.56's with 32" tires. Not bad around town and can make highway trips but I only run about 60-65 because of the RPMs getting higher than I like. Gas milage sucks with the lower gears in it. Sometimes I wish I had only gone with 4.56's.

I'd definitely recommend a limited slip over a locker if you are putting more highway milage on it than offroad. Tru-tracks have a good rep there. Selectable like an Ox or ARB would be best, but expensive. Don't go with the lunchbox lockers. I've run those in my TJ, Might put them back in later as I don't use it as a daily driver anymore. I've worn two rears out. The teeth start wearing about 40K miles and the locker starts slipping. My front is now starting to slip and needs to be replaced. Last issue I had with the rear was on a trail ride. Luckly I had thrown the spider gears in my tool kit just before we left and I was able to just swap them in.

Personally I'd recommend the 33's rather than 35's. I'm partial to a more stock look, and given you aren't doing much hardcore trail riding, 33's would be plenty. It will also help with gearing and stress on the T5 as mentioned before. I might move up to 31's at some point, but I don't see needing more. My scrambler is a daily driver and any offroad will be more gravel road/fields than trails. Trail riding is what I have my TJ for.

Robert
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#8
I regeared my 83 Scrambler when we rebuilt it. I went from 2.73 to 3.54 gears because I didn't want to change the carriers out. As you are looking to go with lockers/Limited slips, that won't be an issue for you. I'm only running a 2.5" lift with 235/75/R15s (about 29" tire) with a 258 and T5. I love the T5. The gearing I have is good for power and gas milage. Before you couldn't hardly get started without slipping the clutch the 2.73's were so bad. I average about 17 mpg and can run 70-75 with no problem and keep the RPMs around 2200-2300. A little higher gearing would be good going with 33's. Not sure if 4.11 or 4.56 would be best. My TJ only has the 4 banger and I put 4.88s in it rather than 4.56's with 32" tires. Not bad around town and can make highway trips but I only run about 60-65 because of the RPMs getting higher than I like. Gas milage sucks with the lower gears in it. Sometimes I wish I had only gone with 4.56's.

I'd definitely recommend a limited slip over a locker if you are putting more highway milage on it than offroad. Tru-tracks have a good rep there. Selectable like an Ox or ARB would be best, but expensive. Don't go with the lunchbox lockers. I've run those in my TJ, Might put them back in later as I don't use it as a daily driver anymore. I've worn two rears out. The teeth start wearing about 40K miles and the locker starts slipping. My front is now starting to slip and needs to be replaced. Last issue I had with the rear was on a trail ride. Luckly I had thrown the spider gears in my tool kit just before we left and I was able to just swap them in.

Personally I'd recommend the 33's rather than 35's. I'm partial to a more stock look, and given you aren't doing much hardcore trail riding, 33's would be plenty. It will also help with gearing and stress on the T5 as mentioned before. I might move up to 31's at some point, but I don't see needing more. My scrambler is a daily driver and any offroad will be more gravel road/fields than trails. Trail riding is what I have my TJ for.

Robert

,

So with the T5 and 4.56 gears I can go with 33's or 35's? If I go with 33's and 4.56 gears would my overdrive not be as efficient to high of RPM's? Your recommendation is welcome.

Trying to understand the tru-tracks since I am regearing already. Is tru-track a Detroit part? Can I put one tru-tracks on the Dana30 and on the AMC20 as CJ7PILOT suggested.

How can I determine how many spline I have either 27 or 30?
 

Rosco1974

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Haven
State
UT
#9
Not efficient, but more fun. Its all about use and driving preference. Some like lower RPM with better MPG for frequent road/highway driving. For that, you can run 3.73 with 33". If you go 4.10 MPG goes down a bit, but better torque. I actually have 4.88s with 33's, but rarely drive at highway speed. This setup is more fun in-town and nice on the trail. These motors produce max torque @ 2300-2500 RPM and rate max HP @ 4200+ so I can run 65 at max torque just over 2500 RPM. I recommend 4.27/4.30 if you are unsure about 35's.

TruTrac is a line of limited slip differential made by Detroit. Have had them and really like/recommend them. You can run them in both with no ill effects.
 

CJ8Rockcrawler

The FABLED 8
LIFETIME
CJ-8.com Member
SOA Member
City
Minneapolis
State
MN
#10
I run 4.10s with a t176 and 35s. To do it again, I would probably go with 4.56s as I now trailer it for any long distances. When I built it, I specifically picked the 4.10s since I didn't have an overdrive. I also have a 4:1 transfer case, so that makes up for the difference off-road vs. 4.56 with the stock t-case gearing.

I run a Detroit locker rear and a trutrac front with no issues in reliability. I am in the process of building a new front Dana 44 axle for it that will have a selectable locker, so my Dana 30 will be for sale.
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#11
Not efficient, but more fun. Its all about use and driving preference. Some like lower RPM with better MPG for frequent road/highway driving. For that, you can run 3.73 with 33". If you go 4.10 MPG goes down a bit, but better torque. I actually have 4.88s with 33's, but rarely drive at highway speed. This setup is more fun in-town and nice on the trail. These motors produce max torque @ 2300-2500 RPM and rate max HP @ 4200+ so I can run 65 at max torque just over 2500 RPM. I recommend 4.27/4.30 if you are unsure about 35's.

TruTrac is a line of limited slip differential made by Detroit. Have had them and really like/recommend them. You can run them in both with no ill effects.
I would like to run 35's that would be my first preference for sure. But I will drive mostly street and 4 to 6 hours road trips so being lower RPM with the T5 would help on MPG. Mostly light to medium off road no rock climbing only back roads ,beach and light trails.

I will add a limited slip to both front and back Dana30 and AMC20 with the 4.56 gears. Your thoughts? Is that a good setup? I do want my 5th on my T5 to actually work and not be under utilized.
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#12
I run 4.10s with a t176 and 35s. To do it again, I would probably go with 4.56s as I now trailer it for any long distances. When I built it, I specifically picked the 4.10s since I didn't have an overdrive. I also have a 4:1 transfer case, so that makes up for the difference off-road vs. 4.56 with the stock t-case gearing.

I run a Detroit locker rear and a trutrac front with no issues in reliability. I am in the process of building a new front Dana 44 axle for it that will have a selectable locker, so my Dana 30 will be for sale.
So based on what your saying you would go with a 4.56 gears with 35"?

I currently have all original but have trouble picking out the Trutrac for both font and rear. What do I need to know before purchasing the Detroit trutrac? Spline 27/30?. Shaft diameter? Sorry this I what I am having most trouble... not experience in limited slips. Any help would be greatly appreciated.
 
City
Huntsville
State
AL
#14
I like this site for checking gears out http://www.grimmjeeper.com/gears.html
I plugged in your numbers for 35's with 4.56 and 4.11 gears. Personally I like the numbers for the 4.11's best (I like to go with lower RPMs for better MPG). Either is OK. Personally I think my 4.2 is pushing it at about 2500 RPM. Wouldn't want to keep it there too long.

With 4.56 gears you get these RPMs:
Gear 60mph 65mph 70mph
1 10585 11467 12349
2 6225 6744 7262
3 3940 4268 4596
4 2627 2845 3064
5 2259 2447 2635

With 4.11s you get these RPMs:
Gear 60 65 70
1 9540 10335 11131
2 5611 6078 6546
3 3551 3847 4143
4 2367 2565 2762
5 2036 2206 2375
 

zr10054

Car and Gun Junkie
LIFETIME
CJ-8.com Member
City
Gonzales
State
La
#15
I like this site for checking gears out http://www.grimmjeeper.com/gears.html
I plugged in your numbers for 35's with 4.56 and 4.11 gears. Personally I like the numbers for the 4.11's best (I like to go with lower RPMs for better MPG). Either is OK. Personally I think my 4.2 is pushing it at about 2500 RPM. Wouldn't want to keep it there too long.

With 4.56 gears you get these RPMs:
Gear 60mph 65mph 70mph
1 10585 11467 12349
2 6225 6744 7262
3 3940 4268 4596
4 2627 2845 3064
5 2259 2447 2635

With 4.11s you get these RPMs:
Gear 60 65 70
1 9540 10335 11131
2 5611 6078 6546
3 3551 3847 4143
4 2367 2565 2762
5 2036 2206 2375

I like the 4:11 gears better.
 

tower210

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Olathe
State
KS
#17
I'd go 4.56.

The 258 is pretty happy between 2200-2700. It's not powerful enough and doesn't like being wrapped up high for either gearset to prevent downshifing at 75. Mine will do 68-70 happy on the highway as long as I'm happy to cruise (32" tires / 258 / t5 / 3.73). It starts getting warm when I want to cruise in the summer at 75. But its a brick shaped jeep. I wish I'd have gone 4.11 when I did the change. Both will be a dramatic improvement over the 2.73. Gear swaps aren't cheap....Measure twice - cut once.

I'm swapping to a 4.0 that likes to be revved more now....
 

Srambler83

Legacy Registered User
City
Houston
State
TX
#19
So definitely decided to go with the 4.56 gears with both Detroit trutrac on both Dana30 and AMC20. Here is my part list and part numbers. Please chime in if you see a potential problem.

Detroit trutrac by Eaton performance limited slip for 29 spline AMC 20 with 3.08 and numerically higher gear ratio Part # 912A579

Detroit trutrac by Eaton performance limited slip for 27 spline Dana 30 with 3.73 and numerically higher gear ratio Part # 912A585

OMIX-ADA 4.56 ring and pinion AMC 20 rear axle Part # 16513.85

OMIX-ADA 4.56 ring and pinion Dana 30 rear axle Part # 16513.17

OMIX-ADA Should I go with a one piece front axle shaft for Dana 30 or should I refurbish the two piece which I currently have?
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#20
I'm still confused about the one piece axle shaft for the front Dana 30... what are you talking about? :shrug:

Everything else adds up to a great setup, and I think you'll be very happy with it! :thumbsup:

EDIT: If you still have two-piece axle shafts in the rear (AMC20), you should definitely upgrade them to quality one-piece axles.
 
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