Topic: Auto Tranny Question

[lax22]

So since all the manual 2.5L's come with factory 4:10's would there be any benefit to adding an automatic tranny in place of the AX5 in order to help turn the 33's a little easier? I know the AX5 will give out eventually i am just wondering if an auto tranny swap would be a better choice for strength and performance? Thanks in advance

[lanulos89]

the auto tranny is strong very strong, but if you do the swap you have to remember you will be going from a 5spd to a 3 spd.  tho you will not break the trans you will go slower, a good amount slower.  for 33's to keep a good speed up you'd want to go to 4.88's prob.  i have an auto and i run 31's and with my stock 3.73's i not only go bad mileage it was a doggggg  i swapped in 4.10's and it was like stock again.

[lax22]

When you say strong you are talking about the 2.5l tranny right? I was already planning on going to 4.88s since thats the lowest gear you can get for our axles from what i understand. I know the only problem is that i have to find out what the price will be for both axles. I am trying to get a set of rubicon axles and i can find a front one locally for about 1900  Hopfully gears wont cost that much.

[Jesse-James]

If you swap in an auto, don't waste your time unless it's an AW4.

[lax22]

Yeah i am still leaning towards the AX15 tranny swap. But i am just looking at my options, I going for the strongest jeep I can build without breaking the bank too much. I want the strongest tranny that i can afford on my budget.

[lanulos89]

yes the 2.5l tranny.  and that is a huge rip off for axles.  get gears you can have front and rear done for like a grand.  since i dont know how to do dears i just searched craigslist and found a set of 4.10's for 200 bucks and swapped housings.

[lax22]

well the one good thing is i already have the radiator with the tranny cooler so i guess i still have that option. I would still add another cooler just to keep things cool . I am looking into prices to see what is the best option. Ill keep you posted.

[Jeffy]

Yeah i am still leaning towards the AX15 tranny swap. But i am just looking at my options, I going for the strongest jeep I can build without breaking the bank too much. I want the strongest tranny that i can afford on my budget.

I wouldn't go with an AX-15.  it is stronger but is plagued with some of the same problems as the AX-5.  You might as well go with a NV3550 instead.  It's a lot stronger then the AX-15.  Dodge use the NV3500 with the 5.2L and I believe the 5.8L too.

[lax22]

Was that also used in the 2000 and up manual wranglers? I would rather do that swap but i think it requiers floor board modifications or at least a body lift to make it work right?

[Bounty Hunter]

The 2.5L auto swap will be a slight improvement in driveability over the 5spd due to the torque multiplication of the auto TC.  I really don't think you'd be satisfied with the minimal improvement compared to the amount of work involved.

[lax22]

Yeah thats what i am thinking but if i was to regear would the difference be more noticable, I was looking into what Jeffy said and even though the cost would be greater the NV3550 swap seems like a good choice. I have alot more research to do before i even touch the tranny so we will see. It just seems funny to me that so many 4.0 jeep guys are looking for 2.5l axles so they can have the 4.10 gearing with their 33's because it can bring them back to almost stock performance from their 3.73. I wish the same was true for us. I am going to stretch this ax5 as far as i can so I am changing the fluid to syncromesh this weekend and I am planning on regearing soon so, to 4.88's so we will see what that dose for me. Problem is I cant afford both axles at the same time so i am going to get the rear gears done first. I dont like idea of using the 4wd with mix matched gearing so i will have to wait untill after x-mas to use the 4wd when i plan on having the front finished as well. This should save some wear on my tranny i would imagine, I am still a jeep noob so i am treading on new territory here but i am loving this thing, even though my wallet isnt hahaha8)   

[nasnop]

I have a '95 auto with 4.56s and 33s. I love it off road (never a complaint of enough power) and around town. On flat highway, I can truck along at 75-80 to problem. The only time I run into issues is long grades or tight, twisty back roads with hills.

Being a three speed instead of a five, you'll run into issues where you'd normally downshift with a 5 speed where the auto is trying to figure out where to be. Often, its either lugging in Drive, or screaming in Second. Basically, there is to much of a gap between gears for a little motor in a heavy Jeep.

I live on the coast and do the bulk of my wheeling two hours inland, so I really only run into power issues on the drives out to big wheeling treks, not in everyday life. That being said, I just bought another '95 2.5 with a 5 speed to see how it drives, and am planning on swapping a 4.0 and a 42RE overdrive transmission from a '95 ZJ into my wheeling rig.

[streetmaster]

The way i understand it is, you almost always figure on 0ne step steeper in the gear set for a 4 popper, than the 6 popper. I've got an 04 with the 2.4L, and the NV1500 5 speed, and 4.11's in it. My jeep came stock with the smallest tire they put on our jeeps, which were 27" tall. The jeep ran like it was suppost to, untill i swapped them out for a set of those uggly ECCO's, ans a set of P225/75/15's and are 28" tall. Even with just one in of height i lost power. If i were to 33's i would have to go with 5.13's to get stock performance like with 27's and 4.11's. If i had 33's with 4.88's, my jeep would have the same power i have with 28's and 4.11's, which is a little lacking. So to get stock performance, you can figure on (4.56's with 31's)(4.88's with 32's)(5.13's with 33's) to stay with in the power band your motor was intended to be in from the factory. I kinda like the look of 32's and a little lift, so im planning in the future foe a set of 4.88's with 32's. 

[aw12345]

I have a 2006, 2..4  which came stock with 3.73 gears Ihad wanted to put 4.30 gears in it but since I gould not get those in a thick dana 44 gear I went with 4.56 gears which actually works out pretty good with 31" tires it has great tires but is a bit short in the top end. With 33" tires top end is fine, but it loses a bit of power compared to the 31" tires. Overall I like the gearing as it is best with the 33" Tires. For 35" tires I would go for 4,88 gears
the regearing is about the best money I spend on my little Jeep

[Bounty Hunter]

Streetmaster, keep in mind that the gearing change, when figured mathematically to match the oem setup, only accounts for the increase in tire diameter.  It does nothing to account for the large increase in rotating mass added when going with larger tires.

For this reason I think it's best to go a little lower on gearing than the mathematical equivelant to oem, helps get the heavy tires moving.