3.07's in a Getrag 4x4 truck?? Who's done it and what do you think?

[Niki]

I ran across a local truck that's a 3 sp auto 3. 07 4x4. I was always curious as to how this would be w/ a 5 sp. Would it make 5th useless, could you cruise on the highway or would you be downshifting all the time? They would be going in a stock turbo/injector truck w/ the pump turned up and a governor spring, and either stock or 265-75-16 tires. Is it even worth the effort? I'm going to be switching diffs anyway, and wondering how much better 3. 07's are than 3. 54's mileage wise. Thanks

 

[KOG]

Probably be alright if you're not going to move over 10,000 GVW or go to larger tires. Be fine for 75+mph cruising. If you're into rock crawling you'll need a double transfer case to get a low enough gear.

 

[MMiller]

I think it would be great in a truck that did not tow heavy, I suppose 10,000# is a good number. It would be great as you could tow in 4th like you are supposed to do, and then run 5th empty. James is going to do a crew cab just like you are thinking about, and will be towing with it. Not nearly heavy as I do. I do also agree that you probably won't want real tall tires, if you are towing.



I've got a 4X4 that had 307's and 727 combo. It had pulled cows, and hay all over south western Iowa,(I'm sure over 10,000#) and it had 165,000 hard miles on it when I recieved it. I switched to 410s and 38" rubber and have wheeled the crap out of the stock 727 so far.



For me the 307's would probably have too tall of a 1st gear to get most loads rolling. I do tow heavy though.



Michael

 

[Niki]

The highest I will probably ever tow would be a bobcat trailer w/ a car on it, probably about 7K. Right now I typically use my beater Camry to drive daily and the truck if I need to haul something, but I've been thinking of ditching the car and keeping 2 trucks, I almost always have 2 anyway. One I'd like to make the ultimate 4x4 mileage machine, 3. 07's, 5 sp, non aggressive 235/85 tires. I just don't want it to be a turtle, because 3. 07's will also magnify the gear splits, especially the 3-4 shift.

 

[JLEONARD]

Deo Reed (therabbittree) put a 3. 07 axle in his 89 5 spd. He was happy with the results when I went for a ride with him last October. I would not call it a turtle by any stretch of the imagination.

Send him a pm and ask.

Jay

 

[therabbittree]

I love mine. . 3. 07 gears W350 SRW . . getrag 360 now in th edspring a late '07 G56 getrag 6 speed is getting swapped in... I have 285 tire . . i plow ans its great . . Easily over 115-120 mph top end if needed. . 55mph in direct gear ie 4th at 1500 rpm. . i plow in low range. . if i floor it in 5th gear od low range i can get about 55mph out of it . . In first gear low range it creeps easy and i have no problems backing or hauling any thing yet. . I like it alot. . keeping it in 1 to 1 around tow helps the trans live and stay cooler and saves fuel. . running 75 on the highway is nice at about 1500 -1600 5th gear I'd do it all over agian in a mintute. . I'm looking for extra 3. 07s as they are harder to find lately. . If i ordered a new 3rd gen megacab I'd order the 3. 42 gears for it and not look back... heck it i beefe my 92 up with a dana 110 axle 3. 07s are available for it. . etc etc... if you ever in my area your welcome to test drive it. .

Thanks,

Deo

 

[Philip]

10k is the best load range for the 3:08's. Anything heavyer you can tow but it takes a while to get speed built up. I have had up to 14k on a trailer behind me. I don't want to do that agin. LOL



The lower RPM realy helps on the inside cab noise at road speeds. You wouldn't think it would be much. But that extra

400 RPM drop makes a lot of difference. Throw a large exhaust with a muffler and it is real quite.

 

[Tippin Spotted Cow]

Do remember that our motors produce their power rather low in the rpm band. Having to low (numerically high) gears in these things just means it turns into a slug trying to pass anyone on the freeway. I have 3. 55s and my buddy has 4. 10s behind a 95 360 V8, but the Cummins has more than enough low end torque to still make him look like a fool off the line, while still runnin lower rpms on the freeway with the 3. 55s.

 

[therabbittree]

I can say mines no slug in passing lane the 45-80mph rush is pretty nice. . no slug here... :-laf

 

[Philip]

Mine has a good 45-100+ rush. Tippin I can run out to 88 MPH in third with my 3:08's. The good part is I still have one gear left to play with. :-laf

 

[Tippin Spotted Cow]

Thats my point, I think that gassers will always find more use for the lower gearing than diesels. Do the math. Our motor's max torque is at what, around 1800 rpm... thats a good 4 grand lower than a V8. From a power standpoint, a diesel always wants to be lower in the rpm band, while a gasser is bouncing off the rev limiter at its peak.



Sure, a diesel with 4. 10s and all sorts of goodies under the hood is still decent at freeway speeds, but put a guy with all the same goodies and 3. 08's next to him at 75. When they both flex their muscles and stomp on it, the guy with 4. 10s isn't even gonna have enough time to read the other guys rear license plate before he speeds off.



All my buddies keep asking me why I keep throwing money into the motor to make the truck faster, but I don't want 4. 10s. 4. 10s will break your neck off the line behind this motor, and after 30mph, when theyve already made their last gear change, then I start to pull away with my 3. 55s, and I would imagine another 20mph later, the 3. 08s would start to make me look like a fool. My buddy's 92 Cummins with 4. 10s winds out at 85mph. Lets just say I've never heard of anyone with a decent quarter mile time crossing the line at 85.

 

[TBartlett1]

I like my 3. 07s. I bought my truck new in 1990 with 4. 10s and I used it hard grossing up to 22k in NE. Many times I tried to find that next gear only to realize I was already there.

I started thinking about 3. 07s years ago and I finally made it happen when the old Dodgezilla succumbed to cancer. I purchased a 1990 with automatic and 3. 07s several years ago in Tucson Arizona so I took the engine & NV 4500 out of my 1st truck and installed it in my 2nd truck with the 3. 07s. I couldn't be happier I finally got that extra gear I have always been looking for. My mpg with the 4. 10s was approx 20. The mpg has now gone up to 23 with my son running it hard to and from school. I think I could get 25 or better on the hi-way if I behaved. Acceleration is better with the 3. 07s because of the taller gears. I usually don't use 5th gear unless I'm doing 50~55mph.

I rarely tow heavy with it anymore but if I need to I would not hesitate.

I think you should do it, you would not regret it especially with the price of fuel.



Tim

 

[therabbittree]

Barlett what tire do you run on your truck? ... I know my 285 truxus mud terrains are eating mpgs . . but heck plowing I get 14mpg satying in low range 4x4 and working... . other wise im about 17-18 mpg. . although haven''t had to many tanks since the flat bed swap. . I'd think it would be better mpg less drag now with flatbed, although may weigh a tad more mummn. . I'd like to get 20 plu smpg. . I never got that though... ... . any tips. . ??? I'm thinking 265 tire - thinner and what not or 19. 5s etc. . oh well less rt foot. . ha

Thanks,

Deo

 

[78cummins-wagon]

I work with a guy that has a '93 with a Getrag 5 speed and 3. 07 and he loves it. He can (so he says) easily do 120 and thats not even pushing it. He sacrafices low end power, though but he says that he can just use 1st if he needs to.