Thanks for responding mwsF250. I was hoping you would. I am not happy with the current performance of my truck. When I get out of a parking lot I want to be able to take off!!!! I don't want someone to rear end me or at least that's the feeling I get with my new 35's. In fact, I am exchanging the Toyos 315/75/R16 with Nittos Mud Grapples 315/75/R16. I think that the Nittos will be better for off roading, because they are a more aggresive tire. I also like the idea that they are loud. The Toyos are too quiet. I already had done gear calculations before I saw this post. With 35's it tells you, you need 4.35 gears. So the closest would be 4.30. Since down the road I might upgrade to 37 or 38's I should consider a lower gear like 4.56. You see I have not gone off roading yet. This is something new to me. I don't even know if I will like off roading. It all started with I needed rear springs and so the spring guy said why don't we add a leaf. So I did. I needed a muffler and I went with a dual exhaust, in fact I reduced the cat to a single because it wasn't loud enough. My exhaust manifold was leaking so I went with headers. This is when I started to want to go off roading. So I needed tires and I went for the 35's and therefore, I needed a 3" lift. Tomorrow I am adding the cold air intake. All I can think every day now is how I can upgrade my rig to go off roading. I have got the bag. So I don't know where I am going with this. In a year I might be in 37 or 38's with a 6" lift. So now would I be better off with a 4.56 , 4.88 or a 5.13 Don't forget I have a V10. THE REAL QUESTION IS IF STAY WITH MY 35's AND GO LETS SAY WITH THE 5.13 WHAT SHOULD I EXPECT
Re-gearing is a fairly expensive job. I don't want to re-gear again next year. The tires I will use or can sell them at a loss. Sorry for rambling but I wanted you to get a better picture of were I have come from and perhaps were I am headed.

 

I think 4.30s would be perfect for a V10 with 35s. I have that setup with my 6.0L now and the only time I don't love it is over 65mph the RPMs get over 2k, but for a gasser that's no problem. If you seriously think you may do 37s eventually, then consider 4.56s, but if you leave it with 35s you'll have a much more useful truck.

 

Hey Backwoods,
Have 6" Rev Tech lift 20" wheels and 37" MT's. My 4x4 guy suggested 488 gears. At 65mph running about 2000rpm. 8-9 Miles per gallon highway or city. I seem to have plenty of power for pulling My 4 Place Enclosed snowmobile trailer loaded down. I dont drive the truck much, it only has 6k miles on it, just use it for long trips and pulling toys and am happy with my set up.

Now for every knowledgeable gear guy following the thread I need some help Have had the gears in for about 700 miles. Have been noticing a fibration around 65-70mph. Washed the truck on Thursday parked it in my shop came out the next day and noticed gear oil under the rear end. Took it apart last night and noticed on the ring gear Lazer Engraved YG-F10.25-488L Obviously Yukon's stamp. On the Ford Tag on the Diff Cover 410 10.5 9j21. So if im reading correctley the yukon ring and pinion is 10.25 and factory is 10.5 would that make a difference??? Is that causing the Vibration? Did my dealer/installer put in the wrong RNP? I'm no mechanic but know enough to get myself in trouble. I dont whant to queston my installer until I get more opinions. Also hand engraved on the Ring Gear is 9M218? Thanks for any help or suggestions. Sorry backwoods for using your thread but i didnt feel mine was worth starting a new one, when yours seemed to have alot of experience.

 

Most aftermarket gear sets for the 10.5 use 10.25 gears, that's not an issue. Who installed the gears? I would try checking the mesh patterns and backlash and see how well they are set up.

 

Hey Cartmanea thanks for the quick reply!!
I donwloaded the info from Yukon and sat underneath my truck for about an hour last night scratching my??? If i am looking at things correctly the Pinion gear is to far away, the wear markes or on the tips of the ring teeth. Is there a better way to check them other than looking at the wear marks? Can I put something on them and then spin the tires?
Thanks
John

 

Yeah, there's some paste/paint you can get at a good parts house for marking gear patterns. Sounds like they were not set up very well. Who did the work? Was it a shop or a buddy? If a shop, I would take it back and tell them of the vibrations and your concerns and have them re-do the setup and show you the mesh patterns when they're done. Do a google search and you can find examples of what they should look like.

 

Thanks for the info. Yes, I did have a local Accessory Outfitter to the install and they are great to work with. Thats my plan on Monday to take it back and ask them to make it right!!

 

Is there a reason for them to use the 10.25 instead of the 10.5?? I paid alot of $$$ for the gears & labor, am i getting shorted by the 10.25?? Any advice would be great on the defferences

 

10.5 isn't really available except for Ford oem, which are about 2X the cost. Everyone running aftermarket gears has 10.25. The difference is the size, 10.5 uses a 10.5" ring gear and 10.25 is 1/4" smaller. The 10.25" gears fit by using a different carrier bearing, so aftermarket never developed the 10.5" gears.

 

Thanks for the knowledge

 

I highly recomend you dont dont get nito mud grapplers! they wear-out super quick, like irok's, after they get to about half like(50% of tread left) there *****. stick with ur toyo's. thats what i have also in 35s. all my buddies run toyo mt's and we all get the farthest when out wheeling, only person who get farther is my buddy and his solid axle yota on 37" pitbull rockers and locked f/r

 

HI BACKWOOD599, Thanks for the tip on the Nitto mud grapplers. Yeah, I know all about that they don't last as long as the Toyos but I like the look of the Nittos. I also like that they are louder.
Are you happy with your re-gearing?
Again thanks.

 

I have 315/75-16's in my V10 with stock 4.30's.

I really wish I had 4.88's. With the 4.30's, it can barely hold O/D when towing. A couple hundred more RPM at cruise would be perfect, and it would also help her get off the line better. When loaded down, she is a bit sluggish. Once she gets wound up over 3K, she goes great and I can easily hang with my buddies' diesels. But in the 0-15 mph zone, they leave me for dead.

If you're not towing, a little less gear may be preferred so the engine doesn't sound as busy and may save 1/2 mpg. What speeds do you cruise at on freeway? For a V10:
If 70 or less, I would probably go 4.56. (4.88 or 5.13 with 37's)
If 75 or more, leaning towards 4.30. (4.56 or 4.88 with 37's)

Personally, I've learned that cruising at over 75 REALLY hurts the pocketbook (regardless of gear ratio!) in these aerodynamically massive trucks, so I very rarely do it anymore. I may get there 10 minutes later, but I also get there with an extra Jackson in my pocket!

 

My 4.56 ring and pinion just arrived and I'm interviewing shops to perform the installation. I got everything from Randy's R&P and think I have everthing I need.

Question: One of the shops asked if I have the carrier for the 10.25 R&P. Is he asking about carrier barrings or something else? I have master rebuild kits for both front and rear. Do I need anything else?

 

I'm just curious, since your rebuilding goal is to build performace have thought about transplanting a 6.8? You would be already building from a strong enough base. Don't get me wrong I love 5.4s. Your going to put some serious money into that 2v 5.4l. The 6.8 has some nice tq. Like I said I was just wondering.
I'm thinking the tq numbers still going to be low on your rebuild. I think 4:56 might getcha by but 4:88 will prolly be better. If still thinking about going bigger when you order your RNP then you might want the 5:12s.