dana 30 gear ratio change?

iv'e got my 30 front axle,now i have to put 5:38 gears in it. can i use the ones out of the 27 or do i have to get new ones. this is gonna get technical for me,ive never changed gears before. i have the haynes manual but i'm sure theres stuff not mentioned ill need to know.

 

you'll need D30 ring and pinion
and the correct D30 carrier/case for that offset

 

This is a job that requires special tools and artwork. Sure - it's a science by textbook terms, but there's truly an art in getting everything correct. I did this change once, and I figured it wasn't critical since it was a front axle. Although, there may be some truth in that, it sure is nice to know the job is done right.
If you have a nearby driveline shop, or speed shop, you might check their price for doing the labor. I had one do my recent Dana 30 for $125, and SO glad I made that small investment...just my two cents.

 

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This is above my knowlege right now but that's why I rebuild/restore these old things(exept the wife,I like her as is). I could pay someone, I could buy one already done. I want to learn how to do this myself. I will pay someone to teach me, that's probably what I'll do, I'm not a complete idiot. I appreciate any and all advise.
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First, take the Haynes manual and throw it in the garbage and buy a Factory/Technical Service Manual that has the correct information.

The 27 gears will not work in the 30.
You may have to change the case in the 30 depending on what gears it has now. 2.54 to 3.54 requires one case and 3.73 to 5.38 gears another case.
IF you have someone competent to teach/lead you to do this then I say go for it. If not then pay someone competent to do that has the right tools. I have lots and lots of dollars tied up just in tools to get them set up right. Dial indicators, gear marking compound, various ACCURATE torque wrenches, bearing pullers, special set up bearings, etc., etc. all factor in. Not trying to dissuade you from doing it yourself but this is the reality of what you may be facing. It comes down to is it worth the investment in the tools to do it right or not for you. Some diffs I've been able to set up in 45 minutes and others I've fought for a couple of days depending on the problems you run into. Quality of parts you are using plays a huge part in getting them set up as well.

 

When you say case, are you refering to the housing? Or part of the carrier?By the way, not going to do this myself, this battle is for another day, just fishing for knowledge.
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The CASE is the part the ring gear bolts to and the pinion and side gears are inside of. The CARRIER is the part that houses the ring gear and drive pinion gear, the case, the bearings, etc. For example, a Ford 9" "third member" is actually the CARRIER. Many people mistakenly refer to the case as the carrier, including magazine writers/editors, and others in the industry who should know better. (sorry but I teach this stuff at the college level and the wrong terminology creates major headaches in communication and proper terminology). What's referred typically as the "housing" includes the axle tubes and ends, in the case of an integral carrier housing the carrier (the axle tubes press into this and are welded in place with rosette welds). An example of a non-integral carrier housing would be a Toyota 8" or Ford 9" where the CARRIER assembly can be unbolted and removed from the housing.

 

Heres a write up on gear installing I found over on pirate4x4.com.. Looks to be a good article, I have not read it all yet myself.

http://www.pirate4x4.com/tech/billavista/Gear_Setup/

 

That is one of the best explanations I have seen.

I set my dana 30 gears up myself with a little help from a friend of mine. But shimming and setting similar stuff like this up is part of my daily job. I have timed a lot of stuff more complicated than this but for someone who has never done it or anything similar it can be very frustrating, especially the 1st time. My main problem was finding info on the pinion depth setting since I didn't readily have that info or how the numbers on the gears actually were used. Once I found that out it was relatively easy.

If you attempt this good luck!!

 

i have done similar things,i mean i have the dial ind. feeler gauges ect.,i just need someone to show me the right way and the short cuts or tricks. i have no doubt i could pull this off but i really dont have the time to do it that way. for now, i'll buy the stuff,read up as much as i can and talk to some people,then i'll pay someone to do it and ask if i can watch them. dan,thanks for the link,its very helpful. also, just how far below 5:38ratio can i go with this engine and tran., i'm not going to be doin any heavy offroad stuff,90% street. can i use 4:10 gears or say around 4:50 something like that?

 

You can't go below 5.38's on a 30. I don't think anyone makes any lower gear sets and the drive pinion gear gets waaaayyyyyy too small which seriously compromises strength.

If you are doing mild off road depending on tire size I'd stay in the 3.73, 4.10, 4.27, no lower than 4.56 gear range unless you are running an overdrive. I have 5.38's with 33" tires and while streetable it is low (no overdrive in my case) so top speed is limited.

 

Mine has 5:38's now,factory I believe. Can I run 4:10's. I recall reading somewhere that the 135,4cyl. Needs that low gearing to get going.(low meaning 5:38).
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5.38's were not factory in a Dana 30. The aftermarket makes gears for them but that's it. Sure you don't have a 25 front? 5.38's were factory in those. Better confirm what front axle you have before deciding on gear ratios. If you are running the F or L head then you won't be happy with 4.10's. We put some in a Scout 80 or 800, forget which, with the 152 slant 4 (more torque and hp than the F or L head) with stock size tires and stock T-90 3 speed (comparable to CJ gearing and tire size) and it wouldn't get into 3rd gear on hills without seriously bogging down. This was for a customer that insisted that's what he wanted. He drove it twice and sold it because it was so gutless.

 

somebody forgot to figure the weight of the Scout into the equation here.....

 

Nope, just forgot to mention it, but when you compare the difference in torque it "almost" evens out...

 

Yes , it is a 25 up front with 5:38's, the reason I bought the Dana was that it has the disc breaks & it's a better front end. I have to match my rear ratio( dana44,w/5:38) I was hoping to be able to get highway driving without a screaming chainsaw on my hands.maybe I'll look at the overdrive addition. what im trying to get here is a more driving friendly mostly street, that i can cruise on the highway at 60mph if i want and not have a hill slug.
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Well, if you're trying to make it more street worthy the path of least resistance and cheapest in the long run would most likely be the overdrive. Bolts right on to the back of the transfer case and you won't have to change gears in the diffs which means you can use what you have right now and keep the lower gears if you do go off-road. You can always gear the 30 down the road and install later.

 

Yeah, that's the best plan I came up with too. Thanks for ur help
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