Brianedwardss
Registered User
Last edited:
Source of 3.08 ring/pinions for 10.25?
- Thread starter Brianedwardss
- Start date
Interesting. With the Dana 70 axle, you cannot fit a 3.08 in it. You cannot put a 3.08 in a Dana 60 either. This is because the pinion gear is too big. To install one, requires moving the pinion gear in the housing a little bit further away from the ring gear, which is why the Dana 61 was invented. Since the Dana and Ford axles are so similar, I would be inclined to think this is true also. But if it turned out that you could put a 3.08 gear in a Ford 10.25, you just made my day!
7.3 powerstrok
Full Access Member
1980s f-350 factory 3.08 gears
some1980s f-350 6.9 diesels only came with c-6 trans and dana axle with 3.08 gear ratio also had left hand thread wheel studs on the drivers side hub ....thinking back 20 yrs ago truck would do easly a 100 mph still pulling at 3300 rpms
some1980s f-350 6.9 diesels only came with c-6 trans and dana axle with 3.08 gear ratio also had left hand thread wheel studs on the drivers side hub ....thinking back 20 yrs ago truck would do easly a 100 mph still pulling at 3300 rpms
david85
Full Access Member
The axle I'm running IS a sterling 10.25 and ford lists this as an option in my owners manual (still have the manual for both my trucks!).
Supposedly the gear spread for the sterling 10.25 is crazy wide and there is no case split as is the situation with dana axles.
The information here suggests they MIGHT be interchangeable, but they aren't very clear on after the 1999. They do say that the R&P and carrier out of an OLDER sterling can fit the 1999 version, but are not so clear about using the newer gears in an older case.
http://www.fourwheeler.com/techarticles/drivetrain/129_0506_ford_1025_1050_inch_axle_tips/index.html
Also note the range of gear ratios is claimed to be 3.08 all the way to 7.17! I think it stands to reason that if ford went through the trouble of having an axle scratch built in the era of needing to offer a dana 61/71 for 3.07 ratios during/after the fuel crunch, that they would try to make a single version to handle as many ratios as possible - even if the later E4OD and ZF5 transmissions made such ratios obsolete (present nut cases excluded, naturally).
There was a time a few years ago when several aftermarket distributors were selling 3.08 ring and pinions for the sterling 10.25, but as Brian eventually told me, they stopped offering them. I've since tried to contact several suppliers that still have listings on their websites, but so far they are all simply errors that have not been updated and none actually carry them anymore.
If that is the real deal, and not some sort of mistake, then it appears he managed to find a hen's tooth!
Supposedly the gear spread for the sterling 10.25 is crazy wide and there is no case split as is the situation with dana axles.
The information here suggests they MIGHT be interchangeable, but they aren't very clear on after the 1999. They do say that the R&P and carrier out of an OLDER sterling can fit the 1999 version, but are not so clear about using the newer gears in an older case.
http://www.fourwheeler.com/techarticles/drivetrain/129_0506_ford_1025_1050_inch_axle_tips/index.html
Also note the range of gear ratios is claimed to be 3.08 all the way to 7.17! I think it stands to reason that if ford went through the trouble of having an axle scratch built in the era of needing to offer a dana 61/71 for 3.07 ratios during/after the fuel crunch, that they would try to make a single version to handle as many ratios as possible - even if the later E4OD and ZF5 transmissions made such ratios obsolete (present nut cases excluded, naturally).
There was a time a few years ago when several aftermarket distributors were selling 3.08 ring and pinions for the sterling 10.25, but as Brian eventually told me, they stopped offering them. I've since tried to contact several suppliers that still have listings on their websites, but so far they are all simply errors that have not been updated and none actually carry them anymore.
If that is the real deal, and not some sort of mistake, then it appears he managed to find a hen's tooth!
82F100SWB
Full Access Member
10.25 and 10.5 gears will interchange, as well as 10.25 long and short pinion. With 10.5 and 10.25, you have to use the pinion bearings respective to the gearset. With long and short pinion, all you need is the appropriate pinion yoke, the housings are the same.
And, yes, ratios are 3.08 all the way to 7.17 with no carrier split, the 7.17 was a factory ratio, gearsets are long out of production and quite rare, but they do exist.
Just keep in mind if you have a 4x4, unless you have a 44 in the front, gear ratios stop at 3.54.
And, yes, ratios are 3.08 all the way to 7.17 with no carrier split, the 7.17 was a factory ratio, gearsets are long out of production and quite rare, but they do exist.
Just keep in mind if you have a 4x4, unless you have a 44 in the front, gear ratios stop at 3.54.
david85
Full Access Member
So the 1999 3rd gen is still compatible with the 1st gen? The 1st and 2nd gen don't seem to have issues but I can't find much info on how the 3rd gen fits in with the earlier two.
Brianedwardss
Registered User
Well, guinea pig time. I searched the web for that part number and found a shop selling em for $207 w/free shipping, so I bought a set. My 88 is already converted to a '93+ spec, and I cant find anywhere that says the ring & pinion changed in 99 regarding 10.25's.
Should have em within two weeks, so we'll see how it goes!
Should have em within two weeks, so we'll see how it goes!
Brianedwardss
Registered User
Just found this:
"The gears in the 99-04 10.25 are a larger and thicker gear. It will not fit the 85-98 F-250/350. It is possible to go the other direction and put a 85-98 F-250/350 ring and pinion in the 99-04 if you use the installation kit for the 10.25". However this ring and pinion would be weaker and could have a much shorter life span."
So, how do the less-thick gears fit the new trucks? Nowhere has a straight answer about 99+ 10.25's. Seems I found an anomaly in the information sources.
If you're wondering why I want a 3.08 over 3.31, right now at 2500 rpm I'm doing 65. With 3.08's, 2500 rpm is 70mph. As far as first gear, right now the C6 shifts at about 15 mph, that will be 16.1mph. It's only a 7% difference, so the slower speeds shouldn't suffer. The real gains are to be made at highway speeds
"The gears in the 99-04 10.25 are a larger and thicker gear. It will not fit the 85-98 F-250/350. It is possible to go the other direction and put a 85-98 F-250/350 ring and pinion in the 99-04 if you use the installation kit for the 10.25". However this ring and pinion would be weaker and could have a much shorter life span."
So, how do the less-thick gears fit the new trucks? Nowhere has a straight answer about 99+ 10.25's. Seems I found an anomaly in the information sources.
If you're wondering why I want a 3.08 over 3.31, right now at 2500 rpm I'm doing 65. With 3.08's, 2500 rpm is 70mph. As far as first gear, right now the C6 shifts at about 15 mph, that will be 16.1mph. It's only a 7% difference, so the slower speeds shouldn't suffer. The real gains are to be made at highway speeds
Brianedwardss
Registered User
Skunked again! Just got an email from the off road shop:
"The part that you ordered has been discontinued. We have refunded your payment. Sorry about the inconvenience"
And what's really odd is the answer I got when I sent a question to the seller with the eBay ad:
"First we do not have stock at this time of the F10308E. The closest thing I have to whatyou are looking for is the F10410L"
His eBay ad is where I got the part number! Guess I'm just gonna go with a gearvendors and call it a day
"The part that you ordered has been discontinued. We have refunded your payment. Sorry about the inconvenience"
And what's really odd is the answer I got when I sent a question to the seller with the eBay ad:
"First we do not have stock at this time of the F10308E. The closest thing I have to whatyou are looking for is the F10410L"
His eBay ad is where I got the part number! Guess I'm just gonna go with a gearvendors and call it a day
david85
Full Access Member
Damn! so close you could almost taste it!
Brianedwardss
Registered User
Seriously! Lately everytime I see my dog chasing his tail, I see me searching for 3.08's
david85
Full Access Member
For what its worth, I was at a local wrecker today and he says he has a few dana 3.07 axles lying around. I'm guessing they are the dana61s but not sure of the condition they are in. It would be a pain to swap out the whole axle though (not to mention a downgrade). He has several high pinion dana44s and dana60 front ends too. I needed to get out of there quick....
I don't get why so few people out there are swapping gears for MPGs with today's fuel prices though. I've been contacted several times by members here and on the other forum asking me about my 3.08s but I guess there just aren't enough of us to make it worth their while.
I don't get why so few people out there are swapping gears for MPGs with today's fuel prices though. I've been contacted several times by members here and on the other forum asking me about my 3.08s but I guess there just aren't enough of us to make it worth their while.
82F100SWB
Full Access Member
The 99+ gears will go into a 97 and older housing, the carrier is the same, so no change in the bearings there. The pinion is larger diameter, but the housing is the same, so the outside of the race is the same diameter. You just need to use the pinion bearings intended for the 10.5 to put a 10.5 pinion in a 10.25 housing. Almost all of the aftermarket "10.5" gears out there are 10.25 stuff.
David, you may find some Dodge D70's with 3.08's, they are somewhat common in 89-91 Dodge/Cummins trucks, but, the first gen dodge diff is a good 2-3" narrower than a Ford one.
David, you may find some Dodge D70's with 3.08's, they are somewhat common in 89-91 Dodge/Cummins trucks, but, the first gen dodge diff is a good 2-3" narrower than a Ford one.
tonkadoctor
Full Access Member
You can Mel. Might be harder to find a set for the 10.25 now but they do exist. I did it 5 years ago before I crossed to the dark, darker then darkest side on my '90 F350 NA IDI ZF5. Remember this thread
Bought them from J.T.'s Parts & Accessories I looked on his website and don't see the 3.08 sets listed anymore but it wouldn't hurt to give him a call and ask.
Biggest pain was getting the correct speedo gear to recalibrate the speedo.
I gained 5 mpg on flat land at 60 mph swapping from 4.10 to 3.08 but the truck couldn't pull a greazed string out of a catz ***.
