Ring and Pinion Ratios

[David70FJ40]

So I am now able to really drive my freshly rebuilt 40 a bit and as I am accelerating the engine sounds like it is turning faster than the tach says it is. At 2500 rpm it is much louder than I remember the other one being. Is there an after market ring and pinion set that can be installed that is more like a road gear with a lower ratio?

 

[Mtbcoach]

One way to make your gears "taller" (smaller ratio) is increasing your wheel diameter (size). If you plan on sticking with stock tire diameter, then regearing your ring and pinion gears might be your best option if you want better road "driveablity".

Or, stick a nice set of 33 X 9.50 tires on your stock wheels and it will give you a bit better road manners. Here is a gear ration calculator that can help playing with tire size and gear ratios...

4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators

 

[David70FJ40]

Currently I am riding on 31x10.50R15LT BFG tires.

 

[Rice]

31's are a fine tire for around town but you won't enjoy highway time. If you decide you must change ratio's 3.73's are available for your diff's if you like.

 

[GLTHFJ60]

There's a difference between a tachometer being inaccurate and your RPM being too high at speed. Are you looking to lower your RPM at speed or do you think your tachometer is inaccurate?

 

[jamesurq]

There's always the torque splitter option. That's what I have with my 69 with a 4 speed. Granted I also have a TBI350, but at 60mph and the torque splitter activated, it's barely 1500 rpm..
760024M-27 : Toyota Land Cruiser 4 speed Ranger Torque Splitter Overdrive 27% | Advance Adapters

 

[David70FJ40]

There's always the torque splitter option. That's what I have with my 69 with a 4 speed. Granted I also have a TBI350, but at 60mph and the torque splitter activated, it's barely 1500 rpm..
760024M-27 : Toyota Land Cruiser 4 speed Ranger Torque Splitter Overdrive 27% | Advance Adapters

Interesting. I will have to come over to look at yours at some time.

 

[jamesurq]

Any time. Not much to see - but a third shifter to the left of the other two, connected to a shiny aluminum box...

 

[Rice]

Torque splitter option works well with a V8 because the motor can be moved forward to compensate for the length of the ranger. Having to move both the tranny and TC back 7.5 inches causes several additions to the "must fab" list.

 

[kulangot]

Your truck came stock with 4.10 gears - you can get some 3rd members that have 3.70 gears in them from a `79 and newer FJ40 or an FJ60 and get a pretty considerable gain in highway speed - or do a bigger tire and accomplish the same thing as Jerry stated. That's what I'd do! 33x10's look awesome on a FJ40 with a Dakar lift and then you can get 34x9.50 TSL's for off road.

If you super tune the motor it will run better at high rpm. I've been Mark Algazy's stock SWB FJ45 going down the 405 at 65 MPH and it sounded like a sewing machine. You have to get the valves, timing and carb just right. Takes a lot of patience or some experience.