Gear ratio sorry

A

Adagusti

Member
Joined
Feb 14, 2024
Messages
44
Location
Australia
Hi guys,
What do you recommend for my wife tj?
It’s a 03 tj 2.5lift 33” tire Dana 30 front and 44 rear 5 speed manual transmission. She struggle on the hills too on third gear, she uses it as a daily drive 90% of the time and maybe a few time on the beach (not much).
Do you think 3.73 or 4.10?

Thanks
 
I have almost same setup Dana 30/35, AX-15 with 33's, I went with 410 because the sets were free. Huge improvement over 373.

Knowing what I know now - I'd have politely declined the sets and gone with 488.
 
DEValken said:
I have almost same setup Dana 30/35, AX-15 with 33's, I went with 410 because the sets were free. Huge improvement over 373.

Knowing what I know now - I'd have politely declined the sets and gone with 488.
Click to expand...

Even if she doesn’t wheel? Seem high, highest I would have said would be 4.56
 
Is the terrain n flat where you reside? Sorry, never been to your continent but I envision very few mountains. If so, 4.56 would be a good ratio. I've had 4.56 in two of my rigs with 33s and the 5 speed transmission with 4.0 engine.
 
Adagusti said:
Even if she doesn’t wheel? Seem high, highest I would have said would be 4.56
Click to expand...

488 puts 75mph at 3k rpm. That is not a high rpm. And it is a lower rpm than the early TJs with the 32rh as they rolled off the assembly line.
 
Here's 411 gears ...

20210102_144710.jpg
 
4.56 or 4.88 for 33s, 4.10s or 4.56 for 31s is my general rule of thumb. I live it the mountains too (southern Appalachian) so I wouldn’t need 4.56 for my 31s, but if I lived out west or in the steeper appalachians that’s definitely what I’d do.
Use this link it’s the best way to decide what gear ratio to go with.
 
Adagusti said:
Even if she doesn’t wheel? Seem high, highest I would have said would be 4.56
Click to expand...

Wheeling is irrelevant. The reason she wants 488 is for daily driving. I’ve been undergeared, am undergeared, and am tired of being undergeared. Test it yourself on the hills your wife drives. How high do the rpm’s need to be to not have to downshift? You’ll discover it’s 2950. Then go plug the specs in the Grimm Jeeper gear calculator and look at the rpm's at 70mph. You’ll see for yourself that 456 is not enough. 488 is my recommendation.
 
I went with 4.88 gears with the 33 inch tires . The throttle is much more responsive and pulls hills much better than it did with 3.73 gears and 30 inch tires . It's not apples to apples because we have the 42rle automatic .
What I did discover after the gear change was that with the driveshafts spinning faster you will find any problems . In my case I ordered front and rear driveshafts from Tom Woods to stop the vibration . The transmission and transfer case make a little more noise now due to the higher revolutions .

Just be aware that changing the gears can lead you down a rabbit hole fixing or upgrading other things .

Going down to 30 inch tires for a jeep mostly used for daily driving may be something to consider .
 
  • Like
Reactions: Tob
Harold&Cat said:
I went with 4.88 gears with the 33 inch tires . The throttle is much more responsive and pulls hills much better than it did with 3.73 gears and 30 inch tires . It's not apples to apples because we have the 42rle automatic .
What I did discover after the gear change was that with the driveshafts spinning faster you will find any problems . In my case I ordered front and rear driveshafts from Tom Woods to stop the vibration . The transmission and transfer case make a little more noise now due to the higher revolutions .

Just be aware that changing the gears can lead you down a rabbit hole fixing or upgrading other things .

Going down to 30 inch tires for a jeep mostly used for daily driving may be something to consider .
Click to expand...

Had you regeared to 513, yours would be closer to the 488 we are pushing for the 5 speed.
 
i went with 5.13 gears for my 4.0 & 42rle on 33’s and it’s way better than the stock 3.73 gears. 5.13 is the lowest gears available for my dana 30/35 axle combo.
 
Top Bottom
Back