Hi ,Anyone running 308 gears with a get rag 5 speed ? If so what are your likes and dislikes . Do you have to start out in 1st gear ? Your rpm ranges through the gears ? Thanks for the inf.

 

I have 3.07's in mine. I usally start in second gear unless on some steep steep hill or I'm creeping along in traffic. 72mph its at about 1700 rpm and a little over 80mph its at around 2000rpm's. Its been a little while since I payed close attention to the speed vs RPM's. I love the 3.07 gears in mine.

 

I would really like to get the 3.08 rear end in mine. I'd imagine the fuel mileage goes up a decent amount. Plus, the CTD would SCREAM through 4th and 5th gear.. i would think anyway. Let's see here.... faster, more fuel efficient, and quieter on the highway hmmmmm

How did your performance change? Acceleration through each each gear etc.. and fuel mileage

 

I have the 410's now and is great when loaded with camper or pulling heavy loads . But I drive mostly empty most of the year and Im always wanting an extra taller gear . At 55 mph it at 2000 rpm . I have a 91 donner truck with 125,000 4X4 . and has the 308's . I was just going to swap the front and back axel assemblies . But didnt want to go through the trouble before I ask someone that has the set up .

 

make sure you hang on to your old axles... the 3.07s are hard to find parts for and you have to swap the entire axle. the guys that have done it love the mod, just keep the spares for when it does eventually wear out.

 

I swapped the getrag in last summer and it works good. I had another truck w/ 4.11s and it was definately gearbound. With the getrag and 3.07's combo I am getting roughly 24 mpg, and towing is WAY BETTER than with the auto. If you have the parts give it a try worst case scenario is that you don't like it and have to spend half a day swapping parts.

 

ditto, cept my truck is 2wd. I went from 727 to getrag. I really enjoyed the mpg increase and the higher freeway gears. I start out in 2nd as well, unless in traffic or parking lot. 4th is a great passing gear as is 5th above 70-75 mph.

 

What is your mph in 1s 2nd and 3rd say at 2000 rpm . Thanks

 

Did the overall acceleration of your truck go up?

 

OK! I have a stupid question. According to my build sheet I have 1 ton axles front and rear with 3.55 gears. Why would I have to swap axles? Can't I just swap ring and pinion? My truck has fuel mileage issues. When Uncle Sam sends my refund my wife gave the go ahead for new(not rebuilt) injectors from Dynomite Diesel. I found a HX35 with 14cm W/G on ebay last summer that I will send to HTT so they can work their magic. And I have been considering 3.08 gears. Any input would be appreciated. I am a newby and love the forum. Thank you guys for the great info.

 

Dodge went to a Dana 61 up front to run the larger pinion gear of the 3.07/3.08 gears and a normal dana 60 front (3.55's and up) doesen't have the extra room for the larger pinion gear. Not sure on the Dana 70 rear.

 

he is right. 3.08 gears will not fit in your dana 61 axle. a dana 60 did not come with gears that low.

 

Same problem. Case carrier and gear are all specific to 3:07, machining would be needed to fit a different carrier to the case, etc. Parts were discontinued by Dana in 97. I almost wonder if the extra toque needed to get them turning is what has kilkled a couple tranny's. I'm not so sure the benefit would outweigh the risk of being stranded if you already have overdrive. I think the air drag robs some of the some of the gain, not all I'm sure. U-joints might even ware quicker too come to think of it. Went through a few of them, luckily I don't have the center bearing to worry about.

 

my acceleration went up on all accounts due to the direct coupling and harnessing of the TQ of the eninge without the loss of power via TC. It's fast, although if you are thinking of drag racing the 727 will win in the end.

 

Also, Dana 61 means a 60 with 3:07 gears. There is no other gear for a 61 than 3:07. I haven't seen where they actually change the nomenclature of a D70 fitted with 3:07's. Ford did use a 61 rear on a few delivery vans, but you can use them on the front of a 4x4 because of different rotation. You could substitue them in place of the 70, but I believe they are narrower and you'll lose some load capacity. Might work good to use on a conversion project on another vehicle though.