Ideal gears for daily driver thats still very rock crawling capaible?

[sheepdog_tx]

Something in the 4.0x range or higher? Thinking i got a 3.08 now but not sure, going to spin test soon.

 

[nvrenuf]

What size tires? Doubler, etc?

Need more info about the truck.

 

[Blue85]

Yeah, what size tires, what transmission, what transfer case?

Although without knowing any of that, I can tell you that 3.08 is not the answer.

 

[sheepdog_tx]

Currently factory everything (30-31s?)

 

[sheepdog_tx]

I do however want to go to 35s

 

[83ChevyK5Blazer]

what is the over all plan for your truck?

 

[sheepdog_tx]

what is the over all plan for your truck?

For its to be used for mixed highway and backroad use, offload capable of doing most 4x4 events. Don't mind giving up a little mpg since I'm diesel but would like to find the sweet spots thats not too much offroad or too much pavement. Right now I got no getup and go.

 

[Greg72]

Work backwards from your preferred highway engine RPM & cruising MPH....

If you have an OD tranny, you can gear deeper in the axles and still have decent highway RPMs.... without the OD, you will have a tougher time getting a good "compromise" setup. You'll have to gear it either for highway or for crawling but it's unlikely you'll do well at both.

There are some good low-range transfercases out there... but with such a small diameter tire your crawl ratios are going to be pretty good even with a factory case.

EDIT: Just saw that you are moving to 35's... factory xfercase may not be as good as I previously thought for crawl ratios..... though I think the NP241 is something like 2.72:1 which is pretty decent.



-G

 

[83ChevyK5Blazer]

I meant over all plan for the running gear, ie: transmission, t-case, tire size.

 

[sheepdog_tx]

So the tran is a 700r4, the engine is a 6.2L diesel. Not sure on gears

 

[paratrooper307]

So the tran is a 700r4, the engine is a 6.2L diesel. Not sure on gears

If you plan on keeping the stock setup, 4.10 or 4.56 should be fine. Since you've got OD, you can gear the diesel similarly to a gas motor and be okay. If you're thinking of adding a doubler, that buys you some gearing flexibility.

 

[82355]

What year is your truck? It is most likely an NP208 (used from 1981-1988). although it could be a (better) NP241 (used from 1989-1991).

Martin

 

[4xcrazy]

TBI 350/NP241 t-case/ 700r4 trans, 4.10 gears and i wished I had 4.56's.

It does fine on the highway, it does lug the engine down a bit at higher speeds in the 65-70 range, likes to come out of overdrive at the slightest little hill.

Does fine off road in low range, could only imagine a bit deep gear would help more though.

I really don't think 4.56's would kill my mileage much more, if at all over the current setup.

 

[sheepdog_tx]

What year is your truck? It is most likely an NP208 (used from 1981-1988). although it could be a (better) NP241 (used from 1989-1991).

Martin

Its an 83 civie 6.2L deisel blazer.

 

[AR_K5]

I'd go with 4.10 since you want to road it with 35's.

We don't have much in common as far as setup goes.
I 'm currently running 3.73's - SB 350, TH350, np241, and run 2000 rpm at 55 mph, but I have a bit more HP than the average 350 so my slightly higher gears aren't such a big deal. It's just my u-joints that suffer since I have a 14 bff / HP-D60.

I admit 4.10's or 4.56 would be better but my toy truck money is currently tapped out.

Have you ran your numbers through the Grimm Jeeper gear calculator?

 

[375 H&H]

I have a 6.2 with 4L80e, NP241 and 4.10s and 33s. it is a decent compromise, and you do have a better first gear ratio with the TH700, ( my only gripe about the 4L80e.) I doubt I'd go lower with the diesel if you need to keep up with highway traffic.

4.10s and 33s is a little lower final ratio than 3.73s and stock tires. 4.10s and 35s is similar to stock final ratio.

all that said, I am installing a doubler. NP241 low ratio is 2.72 :1, and a doubler will give me a gear above and a gear below that, along with 2low (I have lockers front and rear)

 

[tRustyK5]

Having the 700R-4, I'd go 4.56. With 35's your rpms at 65 mph would be 2000. Ideal IMO, even for a 6.2.

I ran 4.56's a SM 465 and 39.5's with my old 6.2 powered Jimmy. Highway it spun at 2600 rpm and it was fine, just really loud. I drove it from Vancouver BC to Moab and back and still pulled down 16.5 mpg.