thoughts on 3:07 gears?

[Los_Control]

I have a chance to get a really nice dana 35 from a 94 jeep, for the correct price .... but it has 3:07 gear ratio.

I told the guy thanks, but no thanks .... does anyone think a 3:07 would work behind a stock 218/3 speed?

Or send it down the road the right thing? Probably going to end up in the scrap yard now.

[Jerry Roberts]

It will work just fine , I have a 2.94 with 218 / 3 speed . If West Texas is hilly country , you might not like it though . 

[kencombs]

JMO, it will depend on your need for the truck.  towing, heavier loads, high altitudes, lots of stops and starts, extended low speed operation or hilly country may not be pleasant with that high gearing. OTOH, mostly lightly loaded, highway 40MPH and up would be great.

[Los_Control]

90% of my driving will be in town, under 35mph and no more then 10 blocks in any direction. (small town)

But would like to be able to drive highway speeds and drive to nearby towns, 30 miles either direction.

Sadly the two lane to the next town with a wal mart, the speed limit is 75mph ... is a backway where speed limit is 55 and probably way I would go.

 

I thank you for your input, I better go ahead and pickup that rear end to have it available

[Dodgeb4ya]

I think way to stiff of ratio for a 218.

The engine is under powered for that ratio IMO.

[41/53dodges]

What size tires are you running? I have 3.55s and 215-85r16s (about 30" dia.) and it's alright, you'd definitely want some smaller tires with 3.07s. By my countilations, about a 26" wheel would get you 2400 rpm @ 60mph

Edited February 20, 2019 by 41/53dodges

[Los_Control]

8 hours ago, Dodgeb4ya said:

I think way to stiff of ratio for a 218.

The engine is under powered for that ratio IMO.

yeah that was my first thought also, and what I originally told the gentleman that has it.

Then thought maybe I would ask and get a second opinion, maybe talk me into it.

 

What bothers me the most while thinking about it...... if I had a T-5, I could downshift from 5th > 4th at highway speeds.

What do you do with a 3 speed at highway speeds, and run into a hill and need to down shift?

Could simply be creating a traffic accident waiting to happen.

[Plymouthy Adams]

3.07 with OD of .70 would give you a 2.14 effective ratio in 5th.....way way high for even many V8's....even the last of the RWD Mopar V8 sedans used a 2.32 and while adequate on the highway for normal driving...they were never rated for trailer pulling for this reason and mainly due to the isolation of both front and rear suspension....

 

Even if you went with a 3.55 which is approx. 2.62 in OD look to downshift....also suggest that you find a T5 from truck where the first and second gears will afford you better ratio for pulling off the line and getting to speed where 3-5 will then be as other T5's.....your 218 while has some torque at lower RPM...it has to build some hefty RPM to develop HP to take over where the torque curve runs out...

Edited February 20, 2019 by Plymouthy Adams

[Adam H P15 D30]

3.0 gears in my Wayfarer became the perfect gear after I changed the rear tires to 26" diameter.  With the 29" tires it was way too tall, I'm running a 230.

[wayfarer]

Play with this online calculator and see what you get....  http://ctny.audiworld.com/mark/s4/gears/gear_calc.html

[Jeff Balazs]

I have a 3.55 in my B-3-C with a later 230. Would not go any higher ratio than that. It is fine for the freeway but when there are hills it could use a T5 with a better spread. There are Cherokee rear ends out there with 3.73 ratio that would probably work perfect for your truck. Just my opinion.

Jeff

[Old CWO]

On 2/20/2019 at 5:34 AM, 41/53dodges said:

What size tires are you running? I have 3.55s and 215-85r16s (about 30" dia.) and it's alright, you'd definitely want some smaller tires with 3.07s. By my countilations, about a 26" wheel would get you 2400 rpm @ 60mph

I have the same configuration in my truck; 3.55s and 215/85R16, 4 speed.  It's a dog out of the hole, plain and simple.  I have a T5 rebuilt and ready to go in when the weather improves around here.  I went with the 4.03 first gear trans as that makes the 3.55/30" tire combo gearing  nearly identical to OEM 4.10/original tires at the bottom end.

 

I think the other big gain potential is an extra gear split in there.  Manual trannies from the 70s and back usually have big RPM drops between shifts. The 218 doesn't have the mojo to make up for it while driving in modern traffic.  At least in my opinion.

 

I'm not even opposed to dropping the axles down to 4.10 after the trans swap if it still seems a little doggy while rowing through the gears.  I once had a 2.5L Jeep Wrangler with similar trans ratios to the T5, 4.88s and 33s.  It was fantastic around town and only buzzed a little high at speeds of 70 and above.  Speeds a lifted Jeep (or 50s truck) shouldn't be driven at anyway...