Dana 20 or 300

[chris486372]

Hi everyone I am new to this sight and I have a few questions someone can probably help me with I have a 1985 CJ-7 Frame I am building for a trail rig I am going to run 35's I have a set of J-10 axles dana 44's I am thinking about runing 4.56 gears in. I can either run a bored 258 or a stock 360 in my jeep if I run a 360 I will back it up with a Quad-trac If I run the 258 I can either run a T-5 with a dana 300 or a 3 speed with a dana 20 can anyone help me firgure out what the best combo is????

[Whitelighting]

I suggest you use a T-18 out of a Ford truck and the 300 transfer case . The T-18 is bullet proof , 6.32 1st gear and you are able to keep a reasonable drive shaft lenth . From 1976 to 1979 the CJ-5's & CJ-7's use the Tremec T-150 transmissions , with the 258's & 304's , those transmissions have the same bolt pattern as Ford . Advance Adapters makes an adapter that adapts the T-18 transmission to the 300 transfer case . The 300 is stronger than the 20 , plus low range is lower geared (2.62 : 1) . This combination gives you a crawl ratio of 75.5 : 1 .

[chris486372]

What gear ratio would I be better with 4.56, 4.88, 5.13? Running a 258 with a t-18 and a dana 300 with 35's maybe 37's?

[Sully]

If it's going to be a trail rig go as low as you can go. 5.13.

[Whitelighting]

What gear ratio would I be better with 4.56, 4.88, 5.13? Running a 258 with a t-18 and a dana 300 with 35's maybe 37's?

Suggesting a gear ratio is a tough call , my priorities might be very different than yours. The rpm's I'm turning at 65 mph is just as important to me as the rpm's I'm turning at 1 mph. If I have to drive at 45 mph to get to Moah, I'm not going to Moab. If I was running a T-18 with a 300 and 35's I would choose 4.56's. At 65 mph the rpm's would be 2845 , which I feel would be respectable. The crawl ratio would be 75.5 : 1, so at 1mph the rpm's would be 725. If you decided at a later date that your crawl ratio was to high you could put a 4 : 1 reduction kit in the 300 and your crawl ratio would be 115 : 1.

[D4x4Fish]

I'm running a T5 with a dana 300. with 35" tires 4.56 gears daily driver 50 miles round trip. carbed and still get about 15 to 18 mph. My future plans is to put in the 4to1 kit. When I lost 3rd in my T5 I really wanted to switch over to the NV4500. but due to the fact I could not have my jeep down for any lenth of time I had my T5 rebuilt. $1500.00 (yea call me stupid) But time is money.

As far a 6cyl or 8cyl I never would have believed I like the torqe of the 6cyl. All thou I due miss my horsepower of a Bigblock. But don't miss the cost of repairing all the broken parts.

Future plans would be FI chevy 350. But not here in California.

This is my first jeep (was a Chevy fan) Been 4bying Almost all my life. Being raised in Wyoming, Hunting, Working, fishing while working, hunting, scoutin the next trip. My Dad was a Old timer of Jeeps, Thats what I learned to drive in (if thats what you call it)my wife made me put that in.

[Davisrats]

dana 20 or 300

I have a 1980 CJ7 with a 258, T176 and a dana 300. I am putting a 4.0 AX15 and a dana 300. The novak adapter worked great.

The T176 is the ford pattern, but the AX15 with bell housing goes right on.

Ron

[tarzan]

i have a 79 cj5 with the 304 v 8 i had the t150 3 speed and the 20 i stayed with the 20 and went with the ford np 435 witch has a great first gear with 33's and i have 354's witch is a great highway gear i have all the tork i need the np 435 with a 300 would be a great combo i think because the 300 has a lower 4 low than i have i like my set up if i need more than ill do a 3 to 1 kit for a lower 4 low