4.636 Regear

[csutke]

Not sure if this has been posted or not but im getting really busy and dont have time to look through all of the posts(and yes i searched) what exactly would it take to do a regear, currently i have a 98 R50 with the 4.363 and im looking at getting the 4.636 because im planning on getting bigger tires and would like to save some on gas as well. So my question is what all would it take to complete the regear, costs, supplies etc... Also is this the only option that is avaible for a rear gear of are there others?

Thanks

[tmorgan4]

For the R50s the only two gear ratios are 4.3 and 4.6s. The easiest way to upgrade to the 4.6s is to buy a complete 3rd member for the rear (to avoid paying another $200 for someone to set up your new-used gears). This will bolt right in and is simple to swap out. This can be taken from any 96-00 Pathfinder, 00-04 Xterra, and I believe 00-04 Frontiers.

 

Easiest for the front would be to swap the whole differential. This MUST come out of another R50. Gear setup is expensive so you'll be paying someone $200+ to set up the gears for the front too. Most places don't seem to charge much more for the entire axle than for the differential and gears. One local place I pulled gears and a locker from told me I could HAVE the axle housing and shafts from a H233b since I bought the center chunk and the rest wasn't worth much. Unfortunately I don't have room to store it.

 

I know of one local place that has 2 or 3 R50s. I haven't ever looked to see what gear ratios they were, but it's definitely worth checking out. They've got pretty good prices.

Edited May 21, 2007 by tmorgan4

[nissandoms47]

Does it really make that much of a difference though? Going from 4.3s to 4.6s. I'm on 33s and I can barely stay at 70 and be under 2700 rpms sometimes.

[88pathoffroad]

You'd get better mileage on stock size tires with the 4.3's. Going up to 4.6's will lower your mileage because the engine would now have to turn the diffs .3 times more revolutions per rotation that it would with the 4.3's. My old 76 Chevy has 2.73 gearing for just that reason, they were aiming for beter fuel mileage on the freeway, at a sacrifice of acceleration and speed. They call 'em "freeway flyer" gears.

[XPLORx4]

On the R50, 4.3's were tuned to put the engine in its powerband when turning 28" (235/70R15) tires. When upsizing to 31" tires with 4.3 gears, the engine doesn't have enough power to keep a steady 70mph cruising speed in overdrive because the RPM's are too low, so the tranny constantly hunts. Add to that the 10% speedometer error, and the perceived fuel economy is even worse! If the engine had a little more HP, the Pathy probably could have been geared higher. In fact, that's probably why 3.5 liter R50's have 4.363 gears instead of 4.636!

 

As tmorgan pointed out, the cheapest and easiest way to regear is to find a used set of diffs at a wrecking yard.

 

You need one of these:

 

and one of these:

 

If you get the front and rear chunks, you don't even need to pay for gear setup. It's a straight remove and replace!