1978 Dana 30 Question

I ended up with a free dana 30 from a 1978 cj5 with a 4.2/t15/dana 20. Is there any chance the factory gears match my 1970 cj5 225/t14/dana 20 rear dana 44?

 

Little chance unless something was changed.
1978 CJ standard ratio was 3.54

1970 CJ with V-6 the standard ratio was 3.73 with 4.89 as optional

 

1978 also had optional 3.73. which is what's in my Jeep. I think they came with the towing package I ordered.

Jay

 

it's easy enough to check. remove the cover, rotate the ring gear until the numbers are visible, divide, and you have your answer.

 

Yeah I know it's easy enough. Just figured I would ask if it was possible before having to silicone the cover back on

 

I have a 30 out of a 79 CJ7 and it matched the 3.73's in my 69 CJ5 axle

 

I think Ken is right ... no 3.73 from the factory in the CJ '76-79. This is what my factory parts book says. There is no listng for a 3.73 axle for a CJ after 1975.

'76-78 it was 3.54 std, 4.10 opt. In 1979 the 3.07 ratio was also optional.

Also there was no T-15 in the CJ in 1978. Maybe the OP is thinking of the T-150? Different... not a Borg-Warner transmission.

 

My 78 " big brake" 30 had 3:73 in it. Its 5:38 now

 

Yeah I know 4.10 was the post 1975 optional ratio.
I think perhaps 4.10 was common on the offset flanged Qudra Trac axles ???

 

I have never seen 4.10 from 76 to 79. It was the 4 cylinder ratio starting in 80 though.

 

I got a guy willing to sell me a matched set of 4.10 Quadr Trac's right now for only $200.
But then I'm not very up on the post 1976 CJ's

 

Looks like the tag on my d44 rear shows 4.89. Does that make sense?

The first d30 I got has 3.54. Picking up the second tomorrow from a 76 cj5

 

Yeah 4.88 is a very desireable ratio to run.
4.88 is a desire able ratio for trail useage
4.88 is especially nice if you have Dauntless power and 25% O.D. unit.
4.88 times 25% O.D. yields a compound FDR of 3.66. which is very nice on hiway

 

Thanks. Since you mentioned the overdrive and final drive ratio, I was actually debating the 3.54 set since I have half of it or going to something in the middle like 4.10. But I like the idea of the overdrive too...

 

And speaking of highway use, I got up on the highway and drove about an hour south to loom at some parts and my old girl on 33s at 65mph actually got 15.5 mpg according to Google maps distances and my gas receipts