Been considering a gear swap. - Diesel Forum

sojerguy · 05-14-2006, 12:51 AM

Amongst the many other changes being considered for my baby. Whats the overall opinion of the feasibility of changing out the diffs from the 4.10's I have to 3.55s? Fairly difficult/impractical or a moderatly difficult swap and what'll be needed.

The truck is primarily used as a daily commuter with occasional 5-6 K tows (maily to hunting camp).

What'll the overall impact to me be?

BuilderBob · 05-14-2006, 01:12 AM

[ QUOTE ]
What'll the overall impact to me be?

[/ QUOTE ]

The cost

sojerguy · 05-14-2006, 04:18 AM

What am I gnereally looking at in cost? Any special changes needed? Or can I just "bolt on/bolt off".

Greg77 · 05-14-2006, 07:40 AM

Just find a complete rearend in a salvage yard with the ratio you want. Drop drive shaft, probably change out brake cables and if your fussy, new U bolts, depending on shape of old ones. The last one we did was $350.00 for the rearend. Depending on salvage yard may be up to $500.00 so check around. You may have to redo brakes and a couple of other small things things but it's a couple hour job and not real expensive. Just be sure to check the free play or backlash in your replacement axle to make sure it's good. Just turn a wheel on one side back and forth and feel how far it turns before catching another gear. If you have a four wheel drive it get's a little more involved, still doable just takes more time and a little more money.

Greg

sojerguy · 05-14-2006, 12:33 PM

Yes its a 4wd. Of course. What year diss can I use in tmy truck and what recalibration will I need for the tranny afterwards?

sojerguy · 05-14-2006, 12:34 PM

"What year diffs can I use ".

tim94f250 · 05-14-2006, 12:57 PM

I'm not sure what year diffs. you can use. As for the tranny, you will need to change the speedometer gear. But, the main reason for my reply is to tell you to never re-use axle u-bolts. The same reason you don't re-use head bolts is why you don't re-use axle u-bolts. They stretch after being torqued the first time you use them. Just ask the guy where you buy your suspension parts if you can re-use the u-bolts. Tim

9ENGEL · 05-14-2006, 01:09 PM

You should have the electronic spedo sensor in the diff, so no recalibration is required.

But that means you need a diff with the sensor.

asauer · 05-14-2006, 01:17 PM

Personally I'd swap to something like a 14-bolt. The 10.25 ford rears we have are junk. They look big but I've never seen one live long that was abused. Seen alot go down because the wheel bearings weren't getting oil and seized up. A 14-bolt is alot stronger and cheaper, and you won't have a problem finding one at all.

brahamfireman · 05-14-2006, 01:23 PM

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The 10.25 ford rears we have are junk. They look big but I've never seen one live long that was abused. Seen alot go down because the wheel bearings weren't getting oil and seized up.

[/ QUOTE ]

got to say I have never heard that one, alot of PSD's making 400 RWHP with this same axle and no problems from "abuse" [img]/ubbthreads/images/graemlins/shrug.gif[/img]

any year axle from '93-97 will work as long as it has the speed sensor in the pumpkin. where are you located???

as for the front end and year D50 will work, all you will have to do is swap out the differential, it bolts to the back of the left TTB.

Diesel Rod

Greg77 · 05-14-2006, 01:44 PM

If you've got a Dana 44 front diff. there are lots of them around. There seem to be more 410's than 355"s and now there are lots of people switching so look around and check a few different places. If you have a Dana 50 those are harder to come by and more expensive. As far as years 1983 thru 1997 should all work.

Greg

Gibson · 05-14-2006, 02:09 PM

what years an be used in you rig???

i had a '95 4x4 stroker that had '87 axles (3:55's) and then we swapped a '94 4x4 stroker axles in its place (4:10). then we traded the 4:10 ring and pinions for a set of 3:55's form a 93 4x4.

so we ened up with:
'95 stroker got '94 axles and '93 3:55's
'94 stroker got '87 axles and '94 3:55's
'93 turbo diesel got '87 4:10's

its all switched around. i feel srry for the guys who got the truck and didnt realize the year modle of the axles/gears... we traded all the trucks a few months ago.... Gibson

sojerguy · 05-15-2006, 08:56 AM

I'm in Iraq, but the rig is in Graham Washington where I'll be in December.

As my profile shows I've checked the driveline as much as possible, but my assumption was that the "50" cast into the front diff meant Dana 50. The rear I read off a the data tag and cross referenced (if my memory doesn't fail me).

Are all Dana diff's of a certain # set at x.xx gearing? In other words are Dana 50 all set at 4.55 etc.... Is there a reference chart about this?

What's this about the 14 bolt pattern?

Myplan is for the 3.55 to get me more mileage on the daily commute and still have enough for my light-medium duty towing.

brahamfireman · 05-15-2006, 09:53 PM

no not all D50's were set to a certain gear ratio. 3:55's were the standard, 4:10's were optional.

The rear is a Sterling 10.25, the early fords were Dana 70's up till I think '92??????

You will be pretty much stuck using a Sterling unless you want to do some interesting fab work, as your speedo has a sensor in the rear diff that it NEEDS to work.

gears out of a Sterling 10.5 will work, these were used in the SD trucks, 3:55's, 4:10's (3:73's and 4:33's were optional) and D50 up front is pretty easy to get gears for if your gunna go new.

Diesel Rod

Mr_Roboto · 05-15-2006, 10:44 PM

[ QUOTE ]
I'm in Iraq, but the rig is in Graham Washington where I'll be in December.

As my profile shows I've checked the driveline as much as possible, but my assumption was that the "50" cast into the front diff meant Dana 50. The rear I read off a the data tag and cross referenced (if my memory doesn't fail me).

Are all Dana diff's of a certain # set at x.xx gearing? In other words are Dana 50 all set at 4.55 etc.... Is there a reference chart about this?

What's this about the 14 bolt pattern?

Myplan is for the 3.55 to get me more mileage on the daily commute and still have enough for my light-medium duty towing.

[/ QUOTE ]

14 bolt is a GM corporate axle [img]/ubbthreads/images/graemlins/shrug.gif[/img] If I was swapping in a non-matching axle, I'd at least use a Dana axle. Ford vans use Danas with the VSS sensor in the housing. I don't know what the width difference is.