Are gears ratio stamped

[Hollowdweller]

Replacing the bearings in my rearend. Diff cover has a sticker that says 3.55. Pulled it apart yest and saw “410” in the ring gear.

My plan is to just swap bearings and put it all back in, didn’t plan on checking anything…bcz I don’t know how. Watched a vid where the guys rebuild kit came with a different brand bearing, Koyo (I think, which is what my rebuild kit has) but I can’t see the brand on the bearings currently on there. They do look alittle different but surely I’d think they’re the same size?

 

[JC SSP]

I have seen ratio stamped on the pinion gear not the ring like what you pictured.

Quoting Google: A surefire way to find your gear ratio is to remove the differential cover and count the number of teeth on the ring gear and the pinion gear. Then, divide the ring gear’s teeth by the pinion’s teeth.

 

[Beanzie]

Alternatively, lift the rear of the car, put a piece of tape on the driveshaft, then turn the tire by hand 1 revolution while counting the number of revolutions the driveshaft spins. ie. 4 and bit =4.10

 

[JC SSP]

Alternatively, lift the rear of the car, put a piece of tape on the driveshaft, then turn the tire by hand 1 revolution while counting the number of revolutions the driveshaft spins. ie. 4 and bit =4.10

CORRECT! Easy way without opening up the differential.

 

[Danny Paladino]

why not just count the number of teeth on the ring gear and divide it by the number of teeth on the pinion gear? that will tell you the ratio for sure

 

[86GT351]

Generally the part nuber is on the head of the pinion. I have seen numbers stamped into the ring gear as well.

 

[Beanzie]

why not just count the number of teeth on the ring gear and divide it by the number of teeth on the pinion gear? that will tell you the ratio for sure

Conversely, why go through all that when if all your after is your gear ratio?
If your diff is out or you are changing fluid, sure why not If you're bored.
The counting of the driveshaft revs is 99.9% accurate and no opening of the diff required.
Imo, that's why.

 

[MrBhp]

Conversely, why go through all that when if all your after is your gear ratio?
If your diff is out or you are changing fluid, sure why not If you're bored.
The counting of the driveshaft revs is 99.9% accurate and no opening of the diff required.
Imo, that's why.

And then again, according to the pics he posted, the thing is sitting on the garage floor completely tore down. Counting the teeth is 100 percent accurate. And the only way he can check it at this time. Unless he puts it all back together and spins it. Then he can take it back apart and count the teeth just to verify. Idk, am I looking at the pics wrong?

 

[GlassTop09]

Replacing the bearings in my rearend. Diff cover has a sticker that says 3.55. Pulled it apart yest and saw “410” in the ring gear.

My plan is to just swap bearings and put it all back in, didn’t plan on checking anything…bcz I don’t know how. Watched a vid where the guys rebuild kit came with a different brand bearing, Koyo (I think, which is what my rebuild kit has) but I can’t see the brand on the bearings currently on there. They do look alittle different but surely I’d think they’re the same size?

View attachment 85150

View attachment 85151

Hi OP,

Just to help out here, the gear set you have is a genuine Ford Performance 4.10 gear set (all Ford Performance gear sets are made using the 2-cut face hobbed machining process.....1 of the visual markers of a face hobbed gear set is the rough finish of the back side of the ring gear where those markings are.......to date only Ford\Ford Performance uses the 2-cut face hobbed machining process to cut all their gears for the Ford 7.5"\8.8" axles........all 5-cut face milled Ford 8.8" back side of ring gears are machine finished thus smooth & are made by the aftermarket manuf's) & Ford marks both the pinion & ring gears w\ the gear ratio number (that is the ring gear ratio you took a picture of) to maintain pinion\ring gear matching.

Otherwise, the methods that others have already mentioned will also get you what you want to know concerning the current gear ratio you have.

Hope this helps you out.

 

[Beanzie]

And then again, according to the pics he posted, the thing is sitting on the garage floor completely tore down. Counting the teeth is 100 percent accurate. And the only way he can check it at this time. Unless he puts it all back together and spins it. Then he can take it back apart and count the teeth just to verify. Idk, am I looking at the pics wrong?

Sorry to misconstrue, I was merely pointing out an alternative method without having to pull the diff cover should someone be curious of their gear ratio.
Yes, his diff is out on the floor, yes I agree count and divide.
However, if u wanted u can mark the yoke, spin the hub and be done, that is unless the ring and pinion have been removed obviously.
Personally, imo, counting the teeth is a time waster, no need.
Again sorry to confuse you.

 

[Hollowdweller]

Awesome…thanks for all the info! I’ll count the teeth to verify. Don’t really want to run 4.10’s with my turbo setup….or should I? I was told 3.73’s I bought for it were alittle to steep and should keep the 3.55’s in there (that’s what I thought was in there).

76mm turbo @14lbs
MMR stage 1 turbo cams…dunno what other info is needed for gear recommendations? Weekend take wife to dinner/movie car, will race anything that wants to lol, prob never see the track

 

[MrBhp]

Sorry to misconstrue, I was merely pointing out an alternative method without having to pull the diff cover should someone be curious of their gear ratio.
Yes, his diff is out on the floor, yes I agree count and divide.
However, if u wanted u can mark the yoke, spin the hub and be done, that is unless the ring and pinion have been removed obviously.
Personally, imo, counting the teeth is a time waster, no need.
Again sorry to confuse you.

No problem dude. Just bustin yer balls.

 

[JEWC_Motorsports]

Hi OP,

Just to help out here, the gear set you have is a genuine Ford Performance 4.10 gear set (all Ford Performance gear sets are made using the 2-cut face hobbed machining process.....1 of the visual markers of a face hobbed gear set is the rough finish of the back side of the ring gear where those markings are.......to date only Ford\Ford Performance uses the 2-cut face hobbed machining process to cut all their gears for the Ford 7.5"\8.8" axles........all 5-cut face milled Ford 8.8" back side of ring gears are machine finished thus smooth & are made by the aftermarket manuf's) & Ford marks both the pinion & ring gears w\ the gear ratio number (that is the ring gear ratio you took a picture of) to maintain pinion\ring gear matching.

Otherwise, the methods that others have already mentioned will also get you what you want to know concerning the current gear ratio you have.

Hope this helps you out.

MY FP gearset only has part numbers, no gear stamps.

 

[Midlife Crises]

Don’t see where you mentioned the transmission your running. If it’s a 3650 then 3.73 is a good choice. 4.10s will just be a little more fun if you like to play with torque. As far as doing the bearing swap. The bearings will be Temkin or Koyo. Both are good brands. It really would be best to have someone with TOOLS and experience help you set the gears up.

 

[JEWC_Motorsports]

And use a solid pinion spacer over a crush collar imo.

 

[Hollowdweller]

The pinion gear is also stamped

Don’t see where you mentioned the transmission your running. If it’s a 3650 then 3.73 is a good choice. 4.10s will just be a little more fun if you like to play with torque. As far as doing the bearing swap. The bearings will be Temkin or Koyo. Both are good brands. It really would be best to have someone with TOOLS and experience help you set the gears up.

I believe it’s a 3650. It’s in a 2006 Roush I bought! Pretty beat up car really but I bought it dirt cheap planning on a full rebuild. I questioned whether it was a true Roush but every thing on it seems to be legit. The instrument cluster turns blue and the dash & cupholders light up blue when I turn on the headlights, install and setup looks cheezy imo! Only “tool” I don’t have from the vids I’ve watched is the backlash gauge. The only reason I’m scared to do it myself is bcz I don’t know how to figure the shims out if it doesn’t test correctly. I don’t have a press either but from what I’ve seen I simply take the shim behind the pinion gear and switch it to the new pinion gear, torque it down and the adjustments come from shimming the ring gear…but I’ve never done it lol. I’m gonna switch over to the 3.73’s I got so I’m gonna give it a shot I guess. Think I can rent the backlash gauge. If I try and it doesn’t test right I’ll just be out a new crush sleeve & pinion bolt I think, may as try.

And use a solid pinion spacer over a crush collar imo.

never heard of this, I’ll look around and read on it but can you post a link so I know what I’m looking at? Thanks

 

[JEWC_Motorsports]

Ford 8.8 pinion preload. No crush washer. Use a solid spacer. - Bing video

 

[GriffX]

https://www.summitracing.com/parts/rmg-04-0011-s

In general take your time, measure shims and so on several times, you don't want to open it again.
Buy some high quality shim set from Yukon or Motive. I had the Ford package with Ratec shims included, bad quality
https://www.summitracing.com/parts/mgr-ss12
https://www.summitracing.com/parts/yga-55002

Beware of the carrier bearing preload (or don't forget like I did ). The Ford pdf is very good. Have fun!

Found Vid