Through the years, the Rocklobster was the only game in town for massive gear reduction. And fairly recently, many distributors of “Rocklobsters” (AKA Rockcrawler, GRSI, etc.) have come onto the scene. I bought mine from Mario at Victory as the first hard-core mod in building my little toy. In my opinion, the Rocklobster is mandatory for anyone who wants their Samurai to be something more than a cool-looking 4WD, and should really be the first mod to building any serious trail Samurai (YMMV).

To help quench my never-ending thirst to build, Build, BUILD my rig…I recently made the (expensive) decision to upgrade my gears again. I bought a Petroworks GRSII. What's the difference? Mainly the 4.89 low range. A Rocklobster lowers your top end 12% and your bottom 83% (4.16:1). The GRSII lowers you 18% in the hi range and 115% in low.

Petroworks sends their GRS to you in an Action Packer box, installed into a nice and clean t-case housing. They include a quart of Mobil synthetic gear oil, install instructions, and a new “hump card” (that yellow thing under the plastic in your carpet) which outlines operation of the “H” pattern. You drop your old t-case, pull the shifter lever out and re-install it into the new t-case, then bolt it back onto the vehicle. The whole procedure took me about an hour which included removing my Con-Ferr belly pan. When it's time to send the core back, Petroworks sends a call tag out with UPS and they pick it up at your door, no charge. Wham, bam, thanks man!

I was running 33s with a Rocklobster and 4.625 gears. This is actually a pretty low setup at 72:1…lower than most 4x4s at any of the jamboree or safari type events I frequent. Some of those giant rocks get gnarly though, and I wanted to be able to go even slower. After installing my 4.625s, I was nervous at the R&P size. To go to a lower gearset (like a 5.12 or 5.38, would really shrink things down). Another consideration…I drive mine on the highway every day and need the speed. That's why I built up the engine and swapped in the 87 tranny for its higher overdrive. I need to have my 70-80mph cruising speed. The GRSII allowed me to lower my final ratio to 83:1, keep my highway speed relatively unchanged, and not weaken my gears. The GRSII and 4.625 equivalent by staying with a Rocklobster is 5.38 gears. This would have killed my highway speed. The GRSII was perfect in this respect.

I have a beef with the GRSII. Cost…$1,200.00 + shipping. If you shop around you can get a Rocklobster gearset for under $700.00 (you'd have to install the gears to the t-case though), which makes the GRSII a pretty hefty investment. To swap one out for the other is for truly hard-core wheelers.

The only tricky thing with the GRSI or II is learning to use the 2WD/4WD high-low setup. It's an “H” pattern, so forget what you are used to. The right side of the “H” is your high and low drive setting. This is the side you will need to be in to actually have the vehicle be in gear. The left side does not put the vehicle into gear for driving, it only determines whether you are in 2WD mode or 4WD mode. Pulling the shifter left and back engages the 4WD mechanism. You then shift back across the “H” pattern; forward for low, and back for hi. To go back into 2WD mode: shift back across your “H” pattern to the left then push the shifter forward. This places the t-case back into 2WD mode. You then slide the shifter back across the “H” to the right and forward for 2WD low or back for 2WD hi.

In a nutshell…

The Rocklobster will work for 98% of all Suzuki owners who want excellent crawling abilities. It is cheaper and quieter on the highway. The GRSII will be more for those nutcases for which money is no object when it comes to the rig. It's excellent and is noticeably lower than a standard R/L t-case when on the trail. If you can hack the noise, I'd recommend it for Sammys running 33s or larger.

If you have any questions on my GRSII…email Off-Road.com at Editor@off-road.com

--Glenn Wakefield