10.5 & 10.5 gears interchangeable... bearings too?

[ZeroOne]

Originally Posted by stunya

thats interesting...i had a set of yukon 4.56s (for 10.25 in a 10.5) in my 02 running 41 in tires and never had a problem in 50k miles...

so whats the difference then with the 08 housing?

The verdict is still out on that. The only known-thing is, there are new install kits for 10.5 gears for 2008-up. Its something about a pinion depth issue. (Which is the problem we had with the 10.25's as well, and why it wouldn't tighten all the way, the right way.) No updated kits for the 10.25's, probably since, that axle isn't even offered anymore.

Randy's Ring and Pinion keeps wanting to argue that the new 2008 install kit is for Ford 10.5 gears and the 10.25's will be fine. What I feel they are missing is... if the 10.25 and 10.5 are interchangeable for YEARS... and you mess with the 10.5 in '08 and now it needs a new kit. Then the 10.25's arent going to fit either.

Lets say pre and post 2008 10.5's are A and B respectively.
If, for gear swaps:
10.25=10.5A
10.5A not equal to 10.5B
than 10.25 is not equal to 10.25B

The only way to know 100% for sure is to go to Ford and get the part number for a ring and pinion set from an 07-previous, and compare that to the same ratio ring and pinion set for 08-up. If the numbers / parts are different, than its the ring and pinion. But I'm willing to bet they are identical, making it a housing change or bearing change.

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Last edited by ZeroOne : 01-16-2009 at 02:54 PM.

[ZeroOne]

As an update to this thread, the truck is back at the original shop now (after a 500mi trip in "front wheel drive" with no rear driveshaft). Now that it's back in, we're getting new 4.56 gears and a new install kit for 10.25 bearings. This time, the kit is designed for the 08. When I had this done last time, there was no such kit yet, and Randys supposedly sent some spacers that should have worked. Hopefully the kit is complete this time around and things actually fit. I'll know more in a day or two when the parts arrive as to whether or not there is still a pinion issue with the 10.25" gears and bearings. Should be fine now... guess it was just too soon last time. IF things still don't go in right, it will be time to change to the 10.5" 4.30's.

[SANDSAILOR]

That looks more like a installer error, dosnt look like they checked the lash or wear pattern.

[ZeroOne]

Originally Posted by SANDSAILOR

That looks more like a installer error, dosnt look like they checked the lash or wear pattern.

Right, but that was the second shop. The first had installed everything correctly, but something with the bearing kit didn't seat properly on the pinion. So bad luck or not the right install kit on the first go-round, then the second shop was just lazy / incompetent, but I had no other place to go, being 500mi away.

[bottledgt]

pinions just dont not tighten up. reason the teeth broke off, is pinion depth was terribly off and contact was only on outer edge. anybody that has any sense could have found out why it fit right or it didnt, not just rig something up to roll.

[ZeroOne]

Originally Posted by bottledgt

pinions just dont not tighten up. reason the teeth broke off, is pinion depth was terribly off and contact was only on outer edge. anybody that has any sense could have found out why it fit right or it didnt, not just rig something up to roll.

The reason the pinion did not tighten properly is because the kit used (that Randy's insisted was always used for 10.25 gears in a 10.5 axle) did not include a very thick spacer that goes between the head of the pinion and the inner bearing. Without this spacer, you run out of threads on the pinion nut before it is tight, on the 2008 and newer 10.5" axles. There IS a difference, that was not known at the time because the truck was too new, last June.

Now, as to how the 1st shop managed to get a good tooth pattern is beyond me, but I know that they did. I'm sure it has to do with a bearing seating further, after the fact / 500mi, since either shims were missing or an incorrect bearing seated further than it initially had, somehow... or failed. It was an error and is being corrected by them now.

Your comment is correct though... the 2nd shop obviously screwed up or didn't care about someone elses installation, and allowed a horrible tooth pattern. Not arguing that fact. I could have done a better job myself in the driveway with absolutely no measuring tools. Being 500mi away from the original shop left me in a bind, and I had no other option.

[ZeroOne]

Just thought I'd post an update for those looking to regear using 10.25 gear sets. I finally got everything straightened out.

A special installation kit is needed for all 08's which has a special pinion spacer. The spacers can be used on both gear sets, 10.5 or 10.25. Also, the master pinion depth will be engraved on the head of the new pinion.

In this situation, we weren't given the spacer initially, then when it was used, the pinion hit the carrier. With all the fuss about the pinion spacer, it is possible that a pinion bearing race was not seated properly, and did not until a long drive. Once it did, without that spacer, the pinion was loose. Took it to a 2nd shop, and without that spacer in place, they simply found a way to tighten it further, bringing the pinion too far away from the ring, causing it to break.

It's all set now. First shop warranted the gears, and fixed everything. Just had to find a way to get there. 500mi in "front wheel drive" with no rear drive shaft worked... but im sure it wasnt the best thing to do. Everything seems fine though. Glad to be done with this mess.

[Live2Crawl]

Ok so Im in this mess with my 09 re-gearing right now. I have a set of motive gears 4:56 10.25 for my 09 F350 and cannot get them to set up .. what do i need 10.50 gearing or a different rebuild kit or what?? after 3 days with this bs its starting to get old..... I cannot get pinion, backlash and pattern to look good its impossible something here isnt right.

[ZeroOne]

Originally Posted by Live2Crawl

Ok so Im in this mess with my 09 re-gearing right now. I have a set of motive gears 4:56 10.25 for my 09 F350 and cannot get them to set up .. what do i need 10.50 gearing or a different rebuild kit or what?? after 3 days with this bs its starting to get old..... I cannot get pinion, backlash and pattern to look good its impossible something here isnt right.

Oh man, I was hoping I would be the only one!

My gears were Yukon but I don't see there being a difference. What we had to do was use a special 10.25 bearing kit that has a specific pinion spacer for the 08-up. This kit will include a spacer that goes between the head of the pinion and the inner bearing. Once you get that spacer in, you can read the numer marked on the head of the pinion (if motive does that) for the initial pinion depth starting point, and go ahead with normal installation.

[Live2Crawl]

So what rear end do I actually have a 10.50 or a 10.25?