37s with 3.92 gears

[Matt Baker]

I know this has been asked several times but I still haven’t got a definite answer yet. I currently have a 2015 Ram 1500 5.7 hemi 8 speed with 3.55 gears. I am running 35x12.50 tires on 22x12 wheels and Superlift 6” lift. I want to bump up to 37s when I replace tires. I know I will have to add body lift to clear tires and need to change gear ratio. What I am wondering is will 3.92 gears be good low enough? I don’t want to do modifications to swap out to earlier front carrier to go to 4.56 gears. I don’t do serious off-roading or rock climbing or pull heavy trailer. I just drive mainly around 20 miles round trip everyday half state highway(55-60 mph) and half city. Once a year or so I do travel out of town.

Also with factory style control arms and ball joints is 37s on 22x12 wheel to much for these ball joints or do I need to upgrade those also.

I know eight the bigger tires even with swapping to 3.92 gears it’s going to be sluggish and won’t be able to pull as much weight but that’s fine. I’m not out here trying to race anyone and I have access to several 3/4 and 1 ton trucks if I need to pull something heavy. I just don’t want to have transmission problems because it’s not geared low enough.

 

[Graygoose]

@CAG CheechDogg has 37' and he swapped gears. But of you already have 3.92's, I dont see the huge upgrade.
On control arms, Id swap to a better, beefier one just for safety sake.


And welcome to the forum!

 

[McBroom]

@CAG CheechDogg has 37' and he swapped gears. But of you already have 3.92's, I dont see the huge upgrade.
On control arms, Id swap to a better, beefier one just for safety sake.


And welcome to the forum!

He may not have 3.92s if its a 2wd. OP didn't specify much about his truck.
I agree with bigger better uca's.
Been awhile since we've talked. What ya been up to Graygoose?

Blue Mule

 

[Matt Baker]

I don't have 3.92 gears. I have 3.55's currently and am wanting to go with 3.92's so I don't have to change front carrier assembly if possible. If 3.92's wont be good then I will just stick with my 35's tires and might still switch to 3.92's. I just don't want to put 37's and the 3.92 not be low enough and cause the transmission to fail/break. I have seen on other threads that some say that it will work and some say it won't be good. I'm not looking for a mud bog truck or anything, just want the look of the 37's and be reliable to still drive everyday and occasionally out of town and occasionally off road but not heavy mudding or rock crawling or anything like that.

It is a 4wd that's why I was talking about having to swap front carrier assembly out because it is welded and can't just swap gears like the older models and like the rear diff.

I was planning on changing the uca's to beefier ones at some point but wasn't sure if needed to be done before I went with the 37's or if I could wait. I will be getting them before going bigger tires. I just put the 35's on it about 2 months ago so I still have a little while before they are worn out. I am just trying to figure out what all I need to do before pulling the trigger and going bigger tires.

 

[Graygoose]

He may not have 3.92s if its a 2wd. OP didn't specify much about his truck.
I agree with bigger better uca's.
Been awhile since we've talked. What ya been up to Graygoose?

Blue Mule

doh, he did state he had 3.55's. my bad.

All has been good, ready for summer!!!!!!!!!!!!!

 

[McBroom]

doh, he did state he had 3.55's. my bad.

All has been good, ready for summer!!!!!!!!!!!!!

I've been ready for the Texas summer since last fall. I like the heat cause the women wear less and less is better(most of the time)

Blue Mule

 

[Graygoose]

LOL....well if we can get past the rain...since Friday, trucks been on point, now...rain for next 4-5 days...uugghhh

 

[CheechDogg.0n37s]

I regeared from 3.21s to 4.88s and I have 37s ... Before I regeared I used to say that you don't need to regear and that 3.21s was plenty even for 37s .....

Look, if you are going to regear for 37s or even 35s for that matter, go with at least 4.56s ...from what I understand you are still going to have to change the front assembly since you do have 3.55s .. so If you are going to have to change front assembly just go with the correct gearing and slap some 4.56s on your truck at least

 

[Matt Baker]

I regeared from 3.21s to 4.88s and I have 37s ... Before I regeared I used to say that you don't need to regear and that 3.21s was plenty even for 37s .....

Look, if you are going to regear for 37s or even 35s for that matter, go with at least 4.56s ...from what I understand you are still going to have to change the front assembly since you do have 3.55s .. so If you are going to have to change front assembly just go with the correct gearing and slap some 4.56s on your truck at least

What all is needed to be done to swap front? I know I will have to get front axle from 2011 or older but what all is needed to get it to mount on my truck? Does it bolt back in the same or is the mounts and all different? I am wanting to go with the 4.56 but don’t know what all will have to be changed/modified. I am just trying to go cheapest and easiest route but don’t want to mess up trans if it’s not geared right. I am fine with it being sluggish just don’t want to tear anything up.

 

[JB1]

Good threads about the swap


https://www.ramforum.com/threads/4-56-swap-completed-total-price-and-parts-needed.123069/

https://www.ramforum.com/threads/2012-4-56-gears-6-lift-lessons-learned.78777/

 

[ram1500rsm]

Your trans won’t explode even with 3.21’s and 37’s.
Just reprogram your TCM for the new tire size at min. (Not required but a good idea for your computer to calculate things properly)
If you change gears you’ll also need to reprogram your TCM for the new gear ratio. This would be required after the gear change. The truck won’t run without the proper gear ratio in the calibration.

 

[CheechDogg.0n37s]

What all is needed to be done to swap front? I know I will have to get front axle from 2011 or older but what all is needed to get it to mount on my truck? Does it bolt back in the same or is the mounts and all different? I am wanting to go with the 4.56 but don’t know what all will have to be changed/modified. I am just trying to go cheapest and easiest route but don’t want to mess up trans if it’s not geared right. I am fine with it being sluggish just don’t want to tear anything up.

Mine is a 2wd so I don't know ... but don't go cheaping out lol ... better to save money and wait a little longer than to do things incorrectly or going cheap.... I know you probably mean cheap as in what is going to be less expensive but even then either gear set up you go with it will be about the same amount.... probably only between 50- 100 difference in price

Sent from my SM-T387V using Tapatalk

 

[6.7CumminsDrvr]

While a regear is nice you might find your current gears adequate for how you described using your truck.

just for kicks, if you use an effective gear ratio calculator, check this out:

with your 3.55’s, moving from the factory 275/60/20 up to 37’s (used 36.8”) nets you an effective gear ratio of.........3.18
Not far off from factory 3.21’s.

you might not “enjoy” the change in performance based on your current tire size but from a mechanical advantage standpoint, you are not stressing that transmission any more than a stock truck with factory 3.21’s........

brakes, wheel bearings and all that is a different story but you won’t hurt the tranny with 3.55’s and 37’s.