Dana 27

I have a Dana 27 with a trashed pinion gear. I ordered and recieved a new ring and pinion set, upon installation I found that the new ring is 7 5/8" in diameter and the existing ring is 7". I called the supplier and they confirmed that they sent me the correct set. I then called another jeep parts supplier and asked them to measure the ring for this axle and that too measured to be 7 5/8" out side to outside. Does anyone know whats going on? The pumpkin has 27A stamped on it.

Any input would be greatly appreciated. Best, Jon

 

Not the right gears. Those are probably D25 sets. The 27 ring should be something less than 7.25" Why an aftermarket D27/D30 cover will not fit on a D25.

 

Yes, I am sure some of the covers will fit both-just like most of the factory covers, but I do not think an ARB 27/30 cover will go on a 25, at least without a lot of grinding, not that I can think of a good reason why you would even buy one for that.

Bottom line is that a 7.5" ring will NEVER fit a D27. Jon, you need to find a different supplier-someone who actually knows what a 27 needs. You may be better off looking for a good used set of original Spicers, even if it takes some time. What ratio are you looking at?

 

An easy way to I'd 27 from 25 gears is to look at the splines on the pinion gear. 27 were fine spline and 25 were coarse. At least on stock parts.
This discrepancy has been discussed in the past and iirc there were indeed two different bolt patterns and ring gear diameters on the 27. Do a search on this. A member did install an ARB cover on a 25 but he had to shim the cover out.
Nothing wrong with putting a heavy duty cover on a 25. The military did it to protect the ring gear. Plus if he upgrades to a 30 it can be used there also.


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John, I appreciate your reply. I know you ran a 25 for quite some time, so you would be very familiar with the ring size. BTW, thanks for all your help with my build, all of your information has always been accurate and useful..

nickmil, yes I did notice the new pinion spline was course and the trashed one was fine, that is information that the suppliers should know. You double confirmed it. Thank you

I think I will make a boat anchor out of this 27 and look on craigslist for a Dana 30, there seems to be an abundance of parts.

Best, Jon

 

What gear ratio are you looking for? A 27 is a decent diff. Maybe a member has what you need? I personally feel a 30 is a good upgrade but.....


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Yeah Nicks right on about the spline count being different.
The D25 used a 10 spline yoke (same yoke 1941-1962)
The D27 used two different diameter yokes.
The Hurricane CJ's used a large yoke. (1310 joints)
The Dauntless CJ's used a smaller yoke.

 

If you go with D30 you'll probably still be looking for a 4.88 gearset.
4.88 was never a CJ standard nor a CJ option for the narrow track D 30

 

Thanks Ken, It would of been a matter of time until I discovered that hurdle...

Yes the gears are 4.88's

.Nick, Please finish your sentence, what are your thoughts on the #30. The D27 I have has been sandblasted, epoxy primed and paited. I just purchased every servicable part to rebuild it (except the R&P). I understand that if I decide to abandon this #27 and find a #30 most of the bearings and seals are interchangable. I purchased the disc brake conversion from Herm and he said the kit will fit on the #30 as well.

So no love will be lost either way, I just want to take the best direction now and try not to waste more money and time.

BTW, there will be a SBC in back of this..

Best, Jon

 

I just meant that if all the 27 needed was a gear set and you could find a set in good shape, nothing wrong with putting it together.

4.88's are not factory for a 30 but are readily available in the aftermarket. Unfortunately not much available aftermarket for the 27.

 

Jon, where do you live? 30's aren't hard to find. Then again, neither are 27s really.

Was there a 27 before the 27A? Is that the change over mark between the coarse and fine spline?

 

Dave, I am from Massachusetts, Boston area. I found a couple #30's on craigslist, but in pieces. We have a lot of foul weather here so the roads are heavily salted in the winters. It is sooo detrimental on vehicles... Nothing lasts here...If salt doesn't do it the Bi laws do...We are not allowed to have one un registered vehicle in open view... so mostly all older vehicles have been sent to be recycled (crushed)...

I have been attending the hunting show in harrisburg, PA for the last 6 years.. While driving through PA, I always say to myself, this is a cool place to live. I see a lot of jeeps in back yards and driveways.. Best, Jon

 

According to the FSM the was a 27, a 27A, and a 27AF. Doesn't say what the differences were. One post here had the 27 using any of the different style joints (Spicer, Bendix, Rzeppa) while the 27A only used the Spicer but there is no confirmation. The 27AF, who knows.

Then I found this post from Ken:
http://www.earlycj5.com/forums/showthread.php?71387-Dana-27AF

 

I thought if you were closer, I could help you out with a 30. Perhaps, after reading the info in the link mortten provided, the F in the 27AF designation, could indicate the fine spline. Maybe?

 

I have yet to see a 27 in any form with coarse splines including Scout versions. Not saying it isn't possible but I've torn down more than I care to think about and have never seen one. The yoke change Ken refers to is the ujoint size change used with the V-6 Jeeps.


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Correct Nick,
there are no 10 splined pinions for the Jeep D27.
Likewise there are no 27 slined pinions for the D25 axles.