How to identify rearend gears?

WaterDog · 11-07-2001, 12:10 PM

Sureset has the right idea. Bait is right as well but as usual he’s making it difficult and messy.

There might be an axle code on the door and you may be able to just look in the owners manual but that would be too easy.

You might check around on the net. I’m sure there a toyota site that will have a BB you can post to. There are good ones for other trucks.

SureSet · 11-07-2001, 12:16 PM

Actually, I tought of another way (purely theoretical), given that you have some way to accurately measure your speed (GPS or driving along side another car that has an accurate speedo) and a tach. If you measure the distance covered by one tire revolution in feet (chalk a mark on the sidewalk), you can calulate the ratio by taking the Speed divided by 60 multiplied by 5280 then divided by the tire measurement to give you axle RPM and then divide Tach RPM by Axle RPM to give you ratio. You can only do that in High gear (1:1 not Overdrive) and it's not very exact, especially if you have an automatic.

Example for tire circum of 6' at 55MPH at 3200RPM

55/60*5280/6=806.6 Axle RPM
3200/806.6=3.97 rearend ratio

SureSet

Pilar · 11-07-2001, 12:17 PM

Maybe you'll find a tag but probably not. It usually is under a cover screw and gets lost when the oil gets changed.

You can get it exact without breaking into the rear end.

Get the rear wheels off the ground with jackstands. Take it out of gear. Have one person count and turn the drive shaft and someone else count the turns on the wheels. Turn until you get 10 turns on the wheels. You'll get the ratio dead on every time.

fishinfreak · 11-07-2001, 01:49 PM

Check this site out. http://www.off-road.com/toyota/tech/other/4_axles.html They have great information regarding Toyota's.

willierower · 11-07-2001, 01:50 PM

What year Toy is it? I know the older 4 banger Toys had 4.10 gears...... What size tire are you running? With 33" tires you need 4.88 gears. 35 to 36" tires you will need at least 5.29's.
Call a dealer ship and give them the V.I.N. They will be able to tell you what you have.

whitewaterbill · 11-07-2001, 02:00 PM

After you get done puting it back tegether....Call a Dealer with the Vin# and have him look it up in the computer at the parts counter.

Bill

Master Baiter · 11-07-2001, 02:41 PM

You can get a rough approximation by counting the number of revolutions of the drive shaft for one complete rotation of the wheel. With vehicle in neutral, place a mark vertical on the inside tire wall where the tire is tangent to the ground and a mark on the shaft, turn drive shaft and count number of rotations (some number of complete turns plus an estimated fraction) till the mark comes back to the origin again.

Gobbaworms · 11-07-2001, 06:46 PM

Several had said to approximate by rotating the tire while counting the drive shaft revolutions. If you rotated the tire 10 times instead of once you can get the exact (closer anyway) ratio. Much easier to tell between 35.3 and 37.3 instead of 3.53 and 3.73

Spooled · 11-07-2001, 09:32 PM

Drifty. Get your 17 digit VIN number located on the dash (you can look through the windshield to get it). If it is a later model, our Toyota store can answer your question with the VIN #. You can reach them at (503)643-9688 ask for Denny, Victor or Al. This will only be accurate if they have not been changed since the truck was new. If it is an older model, these guys will still probably be able to tell you though.

Drifty · 11-07-2001, 11:06 PM

Can anybody out there tell me how to identify what gears I have in the rearend of my toyota?
I'm wanting to get a little better towing performance out of my toyota without changing my tire size too much.

SureSet · 11-07-2001, 11:24 PM

Drifty,

I'm not all that familiar with Toyota, but first look for a ratio or axle code on the ID/Weight rating plate. If no luck, then see if it has a tag on the differental that may have the axle ratio on it, either in x.yy ratio or in xx yy tooth count for ring and pinion (just divide the numbers for ratio i.e. 42 11 = 3.81). Otherwise, you have to look up axle code locations and find a reference. Sometimes you can look at the service manual and determine with certain option you could only have one differential ratio (i.e. you know you have a V6 and STD with a towing package and there was only one ratio for that combo).

You may also look at the front also if it's FWD, they will be very close if not exactly the same. The only other way is to count Drive shaft revolutions to wheel revolutions for a semi-close idea, althoguh you'll never tell the difference between 3.5 and 3.8.

If there's a possibility it's been changed befoe, only counting the teeth on the gears and dividing the numbers will tell you for sure.

Maybe others have a better way.

SureSet

Bait O' Eggs · 11-07-2001, 11:24 PM

Thank god the topic wasnt what I thought it was from the title :shocked: :shocked:

You should be able to pull off the cover on the back of the rear axle and count the teeth on the ring gear and the teeth on the pinion gear and divide one into the other. You should come up with a number between 3 and 5. Of course this would require the cover be resealed back on the axle with some permatex or a new gasket. And when you pop the cover be ready for some oil to run out, which will need refilled.

Or you could take your VIN number to a dealer and they should be able to check with the factory on what gears were put in the rear end