Gear/diff size (TRDOR)

OreoCat

OreoCat

Well-Known Member
I want to regear, but the idiots on TW all gave me different answers and a **** storm happened. Is the TRD offroad the 8 in diff? 8.4? Or is it something else?
 
Also what's your purpose of changing the gears out?
Add a larger tire and want to get closer to factory specs?
Want more low end torque for better off road?
Want quicker off the line time?
 
This diff commonly and mistakenly called an 8.4" or 8.25" diff, possibly to imply its extra strength. The ring gear actually measures 8". The extra strength of this diff comes from the bearing cap/truss and large diameter pinion gear shaft.
LSD's available is the TRD/Kazuma clutch-type 3-pinion LSD, the OEM 4-pinion Tundra TRD LSD, and the Detroit Trutrac.
Lockers available are the Powertrax "Lock-right," "No-Slip," ARB Air Locker, I Detroit Softlocker.

This diff cannot be fitted to an older style 8" axle because it uses a larger diameter mounting bolt pattern and because more space inside the housing necessary to accommodate the large bearing cap. The different bolt pattern also makes it very impractical to swap in an electric locking Toyota diff (the whole mounting flange would have to be re-done using a special jig).

- Carrier bearing truss and newer housing adds significant strength over V6 and 4cyl diffs
- Uses V6 carrier bearings, larger pinion bearings
- Uses shims for backlash adjustment instead of threaded adjusters
- Twelve 12mm Ring gear bolts
- 10mm axle housing studs with 14mm nuts
- 30 splilne axles
- 30 spline pinion

* 4Runners do NOT use this diff at all. Late-model 4Runners still use the V6 8" diff above.

** This diff is NOT swappable with V6, 4cyl, high-pinion, or electric locking diffs. This diff cannot be fitted to an older style 8" axle because it uses a larger diameter mounting bolt pattern and because more space inside the housing necessary to accommodate the large bearing cap.
 
2nd gen V6s are 8.0" for the offroad and 8.4" for all others. 3.73 gears on all V6 regardless of trans.

As stated, the ring gear is 8" on both but there are larger carrier bearings and a truss.
 
OR17TRD said:
Also what's your purpose of changing the gears out?
Add a larger tire and want to get closer to factory specs?
Want more low end torque for better off road?
Want quicker off the line time?
Click to expand...
Bigger tires, I currently have 285/75s and going to 305/65, but when the 305s are done I'm going strait to 37/12.5/17. Planning on 4.88s
 
Some came with 4.88s from the factory! You can swap into your 8” front solid axle, 8” rear axle, or 7.5” IFS. The 8” version will work with 6 cylinder lockers and LSDs.
 
To get as close to stock your highway cruising RPM will be your “goal” RPM. For highway cruising, you need to know:
  1. tire size
  2. gear ratio
  3. transmission’s 5th gear ratio (or whatever the top is)
  4. your typical highway cruising speed
You plug these figures into a calculator and this will tell you your engine’s rpm. Then you take your:
  1. new tire size
  2. transmission’s 5th gear ratio (or whatever the top is)
  3. your typical highway cruising speed
  4. the calculated rpm from above
and you run it through a gearing calculator to give you the “optimum” gear ratio you should be running with those tires.
 
You must log in or register to reply here.
Back
Top