YWST: Low Range T-Case Gear Sets for the 1980-2007 Cruisers

Azca

 
Joined
Oct 25, 2007
Messages
1,141
Location
Surprise AZ.
Fantastic, I'm very excited to hear this! How is your gear noise?
It is there but no where near the noise what my Pro Comp xtreme mud terrains make and they are fairly quiet. Also not a nearly as loud as cutting off the exhaust resonator when I added my 4x4 labs bumper. Now, add these three things together, plus the wind noise from the snorkel, and it gets a bit noisy at 80 MPH. That said, I didn't set this up to be a luxoliner either. Eventually I will have someone mock up a new resonator and use dynomat in the rig but that is down on my list.

If I ever feel the need I may look at the new modified gear but, not sure it is worth my time at this point. I am happy with the performance gain and don't relish getting back into the case again just to make it quieter. If I ran all terrains that may change though.
 

4Cruisers

SILVER Star
Joined
Apr 2, 2015
Messages
4,523
Here are my most recent plans for my '71 FJ40 build:

'76 2F; H41 from an '84 HJ47; split transfer case with drum parking brake from an '85 BJ45; 4.11 course spline differentials; BFG LT235/85R16 ATs on 70-Series wheels. 4th gear ratio (using BFG published tire diameter) at 70 mph (as fast as I'd ever plan to drive it) is ~3,147 rpm, which is a little high. Crawl ratio in 1st gear, low range is ~39.0:1.

Alternative 1:

Same as above but with 3:1 Sumo gears in the transfer case and 3.70 fine spline differentials. 4th gear ratio (using BFG published tire diameter) at 70 mph (as fast as I'd ever plan to drive it) is ~2,832 rpm, which is just right. Crawl ratio in 1st gear, low range is ~53.8:1.

Benefits of springing for the Sumo gears (I already have a spare set of FJ60 fine spline 3.70 differentials with the earlier, correct driveshaft bolt pattern):

Lower (better) highway rpms, lower (significantly better) crawl ratio, and somewhat stronger pinions.

Anything I haven't considered?
 
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