Transfer case 10% under drive or regear 4.88

[albertliang3]

Hi guys. Recently trying to solve my leaky t case, and thinking to throw in a 10% underdrive 4Hi and low ratio 4L. My set up now is 35s, front bumper and rear bumper, no tent yet. I did have a plan in the future to regear to 4.88 and rear locker. But if I put in the 10% under drive gear in now, in the future if I ever consider regear the ratio would be 5.29 combined . I think that is too much, I have no initial to do 37s. So has any one done either under drive and regear. I wanna know how Much is different. And any recommendations would be appreciate.

Thank you!

 

[GTV]

Do you have 4.10’s or 4.30’s?

Did you replace the crush washer on the drain plug? Ask me how I know…

I have both high and low t-case gears and 35’s. It’s much better than stock gears with 35’s but it still leaves me wanting just a little bit more. The extra deep low range is super awesome.

4.56 is also possible.

 

[krice118]

I think if you’re rebuilding the T case swap in the gears anyway…..

 

[albertliang3]

Do you have 4.10’s or 4.30’s?

Did you replace the crush washer on the drain plug? Ask me how I know…

I have both high and low t-case gears and 35’s. It’s much better than stock gears with 35’s but it still leaves me wanting just a little bit more. The extra deep low range is super awesome.

4.56 is also possible.

I dunno about 410 or 430, I just have it stock 02 lx470 4speed auto. Is it big different after you doing the 4Hi? Rn going over mountain pass, is not bad but i know it gonna be better with the more 4 hi. Since doing this and 4.88 is too much of gear ratio, so just debating if I should do 4:88 and stock t case ratio instead.

 

[albertliang3]

I think if you’re rebuilding the T case swap in the gears anyway…..

Yeah that’s my initial doing the gear mod. But I only can choose one between either 4:88 or overdrive t case because combined would be too much of ratio.

 

[GTV]

I dunno about 410 or 430, I just have it stock 02 lx470 4speed auto. Is it big different after you doing the 4Hi? Rn going over mountain pass, is not bad but i know it gonna be better with the more 4 hi. Since doing this and 4.88 is too much of gear ratio, so just debating if I should do 4:88 and stock t case ratio instead.

You have a 4 speed so you have 4.30’s.

T-case high range gears are a 9.7% difference, effectively turning your 4.30’s into 4.72’s. Going to 4.88’s would be a 13.5% difference.

If you really want/need a lower low range then just do those in the transfer case and do 4.88’s in the axles.

 

[MongooseGA]

I'd go 4.88s in the axles, if it was to come down to either/ or.

You'll get the benefit of regear on the street with your 35s. The case gears will only benefit you offroad.

I have 4.88s in my axles and 25% reduction in the t-case. Low range is LOW. If I didn't have an itch to just mess with stuff, I really didn't have a need to do the t case. The 4.88s were plenty on their own in low range and on trails.

Edit: just to clarify, I only have low range reduction gears. I can't speak to the high range set.

 

[albertliang3]

You have a 4 speed so you have 4.30’s.

T-case high range gears are a 9.7% difference, effectively turning your 4.30’s into 4.56’s. Going to 4.88’s would be a 13.5% difference.

If you really want/need a lower low range then just do those in the transfer case and do 4.88’s in the axles.

Woah that’s a lot of math. Thanks for clearing out. What about I do the 10% t case and 4:56 in the axle. Will that be closer to 4:88? I just wanna have a option later to do the axle if I need more out of it.

 

[Dirt J]

Did the high range gears and got all my power back plus some (a bit too low) from my 33s.

Also did the low range and 2WD.

 

[GTV]

Woah that’s a lot of math. Thanks for clearing out. What about I do the 10% t case and 4:56 in the axle. Will that be closer to 4:88? I just wanna have a option later to do the axle if I need more out of it.

The math is pretty easy. 1.097x4.56 = 5.00

 

[matzell]

4:30 x 110% will get you to 4.73 with just the 10% underdrive gears. close to 4:88

 

[MountaineerLC]

Did the high range gears and got all my power back plus some (a bit too low) from my 33s.

Also did the low range and 2WD.

Any effect on fuel mileage?

 

[Dirt J]

Nothing that I could tell offhand. I've never tracked it in this vehicle. It was lousy before and still is after.

 

[hoser]

4.88/4.3/35's is a better match. The speedometer will actually be dead on. But in your situation, the t-case regear would would save a lot of money. You can add that rear locker without touching the front diff.

4.56 is a bit more complicated to do than 4.88's because it requires additional parts.

 

[ClassyJalopy]

4.88/4.3/35's is a better match. The speedometer will actually be dead on. But in your situation, the t-case regear would would save a lot of money. You can add that rear locker without touching the front diff.

4.56 is a bit more complicated to do than 4.88's because it requires additional parts.

Can confirm 4.88 diff gears in place of 4.30 diff gear w/35" tire on an 01 LX makes the speedo dead on and the truck drives like a stock truck on stock 31.5" tires!

 

[OEMGUY0720]

Recently did a tcase for 2000 LC 10% under drive for High Range only, Low Range remains factory and it is getting an additional 3MPG improvement. Has 33s, rear Slee bumper, LRA main and sub tanks.

 

[albertliang3]

Did the high range gears and got all my power back plus some (a bit too low) from my 33s.

Also did the low range and 2WD.

How’s the 2wd affect the handling? Does it need to do certain mod to the t case or just the front end axle stuff like that.

 

[albertliang3]

Recently did a tcase for 2000 LC 10% under drive for High Range only, Low Range remains factory and it is getting an additional 3MPG improvement. Has 33s, rear Slee bumper, LRA main and sub tanks.

Thank you for your feedback. It helps a lot. So I decided to pull the trigger on the 10% under drive since cruiseroutfitter has them on sale.

 

[albertliang3]

4.88/4.3/35's is a better match. The speedometer will actually be dead on. But in your situation, the t-case regear would would save a lot of money. You can add that rear locker without touching the front diff.

4.56 is a bit more complicated to do than 4.88's because it requires additional parts.

Yeah. I saw a factory e locker diff on fb for sale. Might just do t case regear and rear lock. Capable enough.

 

[FamilyCamper]

Thank you for your feedback. It helps a lot. So I decided to pull the trigger on the 10% under drive since cruiseroutfitter has them on sale.

Curious where you see the sale? Just did a search and didnt see anything. Thanks