4low strong enough for racing?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

highperf4x4

Original Male
Joined
May 3, 2014
Messages
280
Reaction score
21
Location
Oklahoma
I need some advice. I'm trying to figure out if I can race my truck in 4low without damaging the transfer case. I'm not sure how the case accomplishes the gear reduction but I could really use it right now. The current engine is only about 425hp. Will 4low take the abuse of mud bogging?

The case is an NP241C
Gears are 3.42
Tires are 33"
 

SCOTTYINWV

si vis pacem, para bellum
Joined
Jun 26, 2013
Messages
12,976
Reaction score
110
Location
West Virginia
You aren't gonna get the tires spinnin too fast. My truck is redlined at like 30 in 5th gear in 4 lo :lol:
 

BOTTLEDZ28

I'm Awesome
Joined
Nov 29, 2011
Messages
894
Reaction score
43
Location
Mass
I would think that 4lo is geared way too low to do what you want. What speed are you looking to get out of your truck in 4lo
 

great white

Retirement countdown!
Joined
Jan 21, 2012
Messages
6,266
Reaction score
209
To anwer the question in the simpliest way: yes.

But, your numbers aren't the best for boggin'.

Mud pits require wheel speed to toss the cleats clean.

3.42, 33's and 4 lo isn't a winning formula. Might get you through, but gonna be slooooow......

If you wanna be competitive in the pits, gear 'er up, drop it into 4 Hi and hammer down.

:)
 
Last edited:

TylerZ281500

Yukon Ridin High
Joined
Mar 13, 2011
Messages
5,858
Reaction score
250
Location
Clinton Township, Michigan
yes but no! dont do it it will go boom at high speeds been there done that. 3.42s and 33s aint helping either its not bad but its not great, itll give you alot of built up heat your tranny and tcase aint gonna like.
 

highperf4x4

Original Male
Joined
May 3, 2014
Messages
280
Reaction score
21
Location
Oklahoma
Here's my set up, My 383 will spin close to 6500rpm. 11:1 compression. The cam is just big enough (operating range is rated 1800-6000rpm) that launching the truck in 4HI by dumping the clutch with the 5speed, the 3.42 gears and the 33" tires brought the engine down pretty bad. My tires are the Dick Cepek Mud Countrys. Pretty knobby. Since the area I was launching from was fairly dry it was difficult to get the fronts and rears to spin. The truck weighed in at 4800lbs last I checked and I've now added another 250lb 6" lift kit. First gear in the 5speed was 4.01:1. First gear in the TH400 is going to be 2.48:1. With the added weight and the higher first gear I can kiss launching in 4HI with the TH400 and the 3.42 gears goodbye. It was difficult to shift the 5speed into second gear while going through the pit. The sticky mud tries to stop the tires the instant I hit the clutch. No matter how fast I tried to shift I just couldn't keep the rpms up. The synchros in the factory 5speed being old made it hard to shift fast anyway. I've eliminated the shifting problem with the TH400. I have a B&M Holeshot 2000rpm stall and a TransGo stage 2 shift kit. The 400 will slam through the gears fast and hard. So, my dilemma right now is the launch. According to the gear ratio calculators, I was able to attain about 40mph of wheel speed staying in first gear with the 5speed in 4HI. If the TH400 shifts out all the way to third gear I will attain 60mph at about 6000rrpm in 4LO with a much harder launch. This is all on paper right now. I haven't installed the tranny yet to test it. My concern is whether the tcase can stand the hp of the 383 in 4LO. I'm not sure how it manages the gear reduction. Additionally the input shaft of the tcase will be spinning at whatever rate the tailshaft of the TH400 produces in 3rd gear at 6000rpm. Something similar to running the truck at about 140mph in 2HI.

I guess I should probably just install new gears in the differentials and be done with it. Since I don't have any experience doing ring and pinions I'll have to pay someone else to do it and that's around 1500 from the quotes I've gotten. Between the 383, the lift kit, the wheels/tires and the tranny upgrade I've already got around 8000 invested in this thing over the last year and a half. I sure hope I get more than one pass out of this thing once it's finished. lol
 

SCOTTYINWV

si vis pacem, para bellum
Joined
Jun 26, 2013
Messages
12,976
Reaction score
110
Location
West Virginia
Is it a daily or just a mud truck? 4.56 however sh!tty with a dd, would get her spinnin quick with 33s. And being able to handle higher rpms with the 383 helps also. For a mud truck, that would probably be your best bet. As a dd, 4.10s would be descent while still streetable.
 

Biggershaft96

Cant Getrite
Joined
Apr 26, 2014
Messages
4,219
Reaction score
1,673
Location
Ligonier, IN
With 425ish hp I would think it has enough ass to get goin. Figure out where your tq peaks and dump it from that rpm. Clutch may not like it so well but that's probably your best bet in my opinion.
 

thz71

Stock SUCKS!
Joined
Sep 5, 2012
Messages
18,176
Reaction score
1,186
Location
Iowa
With all the money you dumped into it you skipped the most important things for a mud truck gears and big tires
 
Top