4Crawler

iTrader: (3)

The 5 speed transmissions have an overdrive in 5th gear, 0.85:1:
- http://www.4crawler.com/4x4/4R_TechI...l#Transmission

Not sure what the ratio is on an automatic, but generally Toyota put higher (numeric) ratios in the axles for the automatics, for example with the 31" tire option, autos got 4.88s while the manuals got 4.56. So based upon that, it looks like the gearing in the automatics is not quite as low as the 5 speed, you you need to make up the difference with the lower axle gearing.

jason191918

Check out my link and you will know.

tc

The overdrive in the auto is 0.71 :eek: MUCH taller than 5th in the manual. SO, if you have an automatic and want it to have enough power to hold the overdrive (not be hunting gears all the time) and lock up the torque converter (to minimize heat in the tranny) you need to gear the axles LOWER (higher number) to ensure the engine is in the powerband at highway speeds.

The factory would gear the autos 1 step lower than the manuals - I think they are still undergeared, and recommend you go 2 steps lower if you have an auto. So, for example, 33's with a manual would be 4.88, but with an auto, I would do the "dreaded" 5.71's. As I drive a rig with 35's and an automatic, I can't recommend it... it's a TOTAL dog compared to 33's with 4.88's on a manual tranny (which I have too LOL)

jason191918

Lucky!

tc

Well, I got the 35's Auto SAS rig with Molly ... so, I don't know how lucky I really am in the end ...

hmmwv15

If I knew I would probably enter the info on 4crawler's website and the one you posted. I think I'll stick to what other's say, I trust 'em enough

hmmwv15

Okay, I've got 29" tires on an 85 4runner with 4:88's. So if I keep the tire size at around 30", I could probably get away with only having 5:29's right? I figure if I do anything to the drivetrain my best bets would be either to swap a manual transmission into it or put 5:29's in it. I figure that re gearing would be the cheapest, but I would like to have a manual anyway. I'll have to see what the budget is in the next few months before I make a final decision.

hmmwv15

So lemme just clarify a bit more;

The first number is how many times the driveshaft spins, and the second is how many times the tires spin right?

jason191918

The driveshaft spins faster.

The engine is the fastest, the wheels are the slowest. Everything keeps stepping down.

4Crawler

iTrader: (3)

Yes, or think Input:Output, so for the rear axle, Input=Driveshaft, Output=Axle Shafts/Wheels. For the transmission, input=engine RPM, output is what feeds into the transfer case.

hmmwv15

Okay, cool! thanks for the info! By the way I got another 85 with EFI and manual tranny!