Hey guys,

I have pulled an IFS diff and am having trouble determining the gear ratio. The number of input turns to output turns seems to vary.

Is there a gear ratio stamped on the ring gear by any chance?

 

I don't know if there is a ratio stamped on the ring gear but if you can count the teeth on the ring and pinion gears then divide you'll get the ratio.

This is how you can get the ratio if the diff is still sealed. Block one output shaft and turn the input flange until the other output shaft has turned 2 complete turns. The number of turns of the input flange is the ratio. If you want to be really accurate go for 20 turns on the output.

 

Makes sense, thank you.

 

the ratio is suposed to be stamped on the ring, it will only be the first 2 numbers IE 4.1=4.10 4.8=4.88, but it isnt always stamped, i had got a 4.88 that was not stamped. the most reliable way is to count the teeth, a 4.10 will have 41 ring gear teeth a 4.88 would be 39 teeth . i use this example becuase this is what i know off the top of my head.

here is a calculator to help you out
http://www.4lo.com/calc/gearring.htm

 

You can also pull it off the vehicle information on the inside of the driver's door frame.

 

They wont always be stamped. Should have a make and model # or some kind of # somewhere on the ring and pinion that you could look up.

or just count the teeth =P

 

you can i have done that before but that always isn't true, they make mistakes with stamping the plates all the time, I would have suggested that but he already had the diff out so to me it makes more sense to me to count the teeth just my opinion.

 

Okay, so the 4.1 stamped on this ring gear indicates to me that these third members are not worth very much money

 

Yep, just count then do da math. But, IF it's a factory gear set it will have the number of teeth stamped plainly on the side of the ring gear. Such as 39,41,43 etc. Oops this post was sposed to be #8, my bad, edit error.

 

Possibly, but not necessarily. They could be custom cryo jobs.

 

borrowing the thread real quick. what would the stock gearing be for a 94' 2wd pu? is it something that u can get options on from the dealer or will it always be the same stock? i tried to look on my diff, but couldnt find anything labeled on it. i'll probally look again. could it possibly be in the owners manual?

 

The VIN # contains a gear/axle code, read this link to decipher. The VIN is located in the engine compartment on the firewall behind the engine, or the door jamb.
http://toyota.off-road.com/toyota/ar....jsp?id=274535

I'm gonna geuss, F072 (3:90)

 

i looked at my diff just now, and while i couldnt rly get a good look at it, cause its wet and i wasnt going to lay down and wiggle in and get all wet, but anyways, i saw the number 10 when looking from the front back. it was on the outer ring that bolts in. mean anything?

 

Isn't the pinion painted? Maybe that is just for the rear axle.

James

 

What's your axle code? If it is F072, then that would be the number of teeth on the pinion. 39 on the ring, 10 on the pinion= 3:90. But 4:10's and 4:30's also have pinions with 10 teeth.

 

No not painted, coated. Similar except it's baked on, the entire gear set and the carrier. A thin layer of a mostly phosphorous compound, IIRC.

If you believe you've seen paint on a pinion it was most likely used as a marking agent when the gears were set up. I've seen it on every type of Toyota axle that I've opened. 2wd, 4wd, front axle, rear axle.