swapping axles

[FMExplorer]

I am going to swap gears later this summer. I have 3.27's now with 3.73's ready to go in. Now (after buying the 3.73's) I am thinking 4.10's. Would it be easier to keep an eye out for a Dana 35 and 8.8 in a junk yard with the 4.10's from the factory? I figure this way I would have all sorts of spare parts. does it make more sense to swap out the entire assembly or just stop thinking too much and do the gears and shut up?

JonM

 

[Scott B.]

I don't believe Ford ever installed 4.10 gears in the Dana 35 and 8.8 (at least up to '94).

Even if you were to get one from a junkyard, wouldn't you want to go through it, and at least replace the bearings? At that point, it is not too much more work to set up the gears.

I should have my Detroit and 4.10s by Thursday - I might just get them installed this weekend. I'll let you know...

 

[FMExplorer]

Scott,
What's in there now?
As far as the acle assemblies went - I figured why not get the newer, rear-disc axle and do the conversion too? Like I have time for that!

Jon

 

[Scott B.]

Jon,

I currently have 3.73s and a very worn Traction Loc. When I was pricing things, there was about a $50.00 difference between the disc brake kit from Ford Motorsports and a complete Explorer rear end with discs from the junkyard. All I had to do was weld on spring perches and shock mounts. While this axle is from a '98, and only has 30K miles on it, it only has 3.27 gears. Can't have everything.

If you get one from a junkyard, you will be able to just bolt it in - the spring perches should be the same.

 

[FMExplorer]

Scott,
Thanks for the reply - that's kind of what I was hoping for. Now the trick is to find a front and rear assembly, or a good rear and re-gear the front if needed...

Jon

 

[flyguy]

Anyone know how to tell what kind of gears your explorer came with? Is there a code anywhere?

Nick

 

[Goober]

Driver side door. There a white little tag kinda just under the armrest on the door jam. Bottom row, better than halfway across, marked..axle. Then go to http://www.users.uswest.net/~ntrpriz/Axle.htm with your code and it should tell you what kind you have. Any other Q's just ask or do a search..

 

[flyguy]

ACK! 3.73 I have. Man.. I thougt they were 3.55 or so... Okay.. whats all this limited slip stuff... anyways... I was planning on getting some larger tires and going 4.10 (is that right?)... but I was assuming I had some 3.55... but if I go to 30 or 31 inch tires... and go to whatever the ratio above 4.10 is... will my truck be drivable? I thought I was pretty slow as it is... hmmm... help!

Nick

 

[flyguy]

Ah, in my ramblings im not sure if I was clear. I wanted to make up for my increased tire size and then have a little bit more torque off the line as well. But I hear of guys with bigger tires than 31s with 4.10s... Suggestions?

Nick

 

[Maniak]

31" tires with the 4.10's is a good combination.. (even works for 32" and 33").. but 4.10's with 30".. I'm not sure about that one.. You would definatly get more bottom end.. but you would kill your top end (you would revving too high)..

The way we figured out (at least to get close) what gear ratio we wanted was to compared the percent changed between the tire change and a gear change..

Stock tire is roughly 28" tall (yes, I'm rounding up slightly).. so.. start with a 28" tire.. and then go to a 31" tire (again rouding up to 31") is roughly an 11% increase.. that means we wanted to change our 3.27 gears by 11% to get back where we started... that would be 3.62 or a 3.73 gear ratio.. That would have us back to stock.. but we wanted more low end.. so we went to a 4.10 gear.. which is a 25% increase in size...

a 25% change in gear means we can change the tire size 25% and still have the stock (or at least close to) acceleration.. which would be a 35" tire..

this is somewhat over simplified since changing your gears doesn't give you all of your acceleration back but it gives you a basic idea of what gear ratio would give you the stock acceleration so you know what size gears you want..

 

[flyguy]

Ah okay.. so if Im running 3.73s with stock now... and I dont like em... I would have to go past 4.10 when I get larger tires... I just hope its not too much... Hmmm... It looks like Ill be getting some new heads before the tires and gears so Ill see how she runs then... before I decide...

nick