4.88's or 5.29's?

[jrabenius]

I have an Isuzu Rodeo that I just did a solid axle swap on using 1984 Toyota Land Cruiser axles. I am running 37" tires, and I need ring and pinion sets.

I also swapped out the 3.2 V6 and the 4L30E automatic tranny for a 4.3 VORTEC V6 and a 4L60E 4 speed automatic.

My stock Isuzu 3.2 V6 put out 140 HP, and 160 Ft pounds of torque.

The (2006) 4.3 Chevy V6 puts out 200 HP, and 260 Ft pounds of torque.

I am running the NV241 transfercase - 2.72:1 low range, and a 1:1 high range.

The 4L60E 4 speed automatic with lock up converter (I think) has a 60% overdrive.

I've changed so much that I'm not sure what gear ratio to run.

I have a choice between 4.88's and 5.29 gears.

I'm leaning towards the 5.29's, but the two 4WD shops here in Albuquerque have said that's too low, and to run the 4.88's.

Marlin Crawler's website suggests the 5.29's for anything over 35" tires.

What does everyone think?

I mostly rock crawl / trail run here in the Southwest - Arizona and New Mexico.

I have a Detroit Locker in the rear, and (currently) open in the front (ARB to come later).

The truck is a daily driver, and needs to be able to be driven at freeway speeds (70 MPH cruise). I plan on driving it to MOAB and other areas out of state on occasion.

 

[Tigerstripe40]

Do you have a full floater rear end?
If so, you can run the 5.29's
If not, 4.88 is the lowest you're going to be able to run.

Imho, just run the 4.88's.

 

[90FJ]

There's a lot of guys with 5:29s and semi-floats here on the board, some had to do some grinding to fit and some didn't.

I really think this has more to do with your choice of drivetrain, go post this question on a Chevy board. If it was me I'd go 4:88s, you should have plenty of power and they are less prone to grenading.

Sounds like a cool rig, post pics.

 

[cruiserAUS]

I have a soa 60 with 2f , 37's and 4.56. I can sit at 70mph @ 3k rpm. I would like an h55 or crawler gears to help offroad a bit but its great on the street

 

[lehiguy]

I would say 4.56 or 4.88, although with 4.88s you will have to actually grind off some of the ring gear to get the spider pin in the carrier. I am not comfortable with that. With 4.56s you will need to grind some of the pin, that is all.

 

[Tigerstripe40]

I would say 4.56 or 4.88, although with 4.88s you will have to actually grind off some of the ring gear to get the spider pin in the carrier. I am not comfortable with that. With 4.56s you will need to grind some of the pin, that is all.

When I did the 4.88's ~3 years ago, I ground down 1 tooth of the gear and it was in an area where the pinion doesn't make contact. No issues.

 

[jrabenius]

I would say 4.56 or 4.88, although with 4.88s you will have to actually grind off some of the ring gear to get the spider pin in the carrier. I am not comfortable with that. With 4.56s you will need to grind some of the pin, that is all.

Good to know. Since I haven't done this gear install yet, I'll ask a dumb question.

Why not assemble the differential first, then bolt on the ring gear? It is a drop out, so you should be able to do that first. then install the diff assembly in the axle housing, install the axles . . .

I guess I'll find out soon enough.

 

[Elbert]

my friend who installed 4.88 on my truck had to do some minor grinding to make it work...similar as noted above. 86 FJ60

 

[lehiguy]

Good to know. Since I haven't done this gear install yet, I'll ask a dumb question.

Why not assemble the differential first, then bolt on the ring gear? It is a drop out, so you should be able to do that first. then install the diff assembly in the axle housing, install the axles . . .

I guess I'll find out soon enough.

C-clip axles, can't do that.