old ganny gear trans.
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old ganny gear trans.
I have a truck that is over 50 ton years old. (1 1/2 ton) That is powered by a 460 ci. mill with a 4 speed trans. (the old 80s granny gear). Built to be a work truck. To pull a 40 ft 5th wheel trailer. Well since gas prices have gone up.I have been looking to gettin better mileage. A few days ago while talking to a friend. He gave me a late model H.D. 5-speed out of a late 90s 1 ton truck. But the is one problem. He saying 5 gear is gone. So I will have to get a 5 gear. But thats ok. My question is do you think it will inprove my gas mileage. I think 5 gear in those transmissions are a lot higher the the 4 speed. Im thinkin all I am going to have to do beside geting the 5th gear replaced is maybe,cutin the drive shaft or have one made longer and maybe a new trans cross member.. Thanks !
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Joined: Apr 2004
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If 5th is gone on what is probably an ZF tranny, I'd be checking out the price of a rebuilt ZF.
You could be into this $1500 easy.
I'd guess you are getting 7 to 9 MPG? A 10% improvement would be less than 1 MPG.
Let's pretend you get 8 now and with the new tranny and a wax job you get 10.
And let's pretend it costs $1500 to fix swap and fit that 5 speed, and gas is $2.00 gallon.
The big pretend is you drive 15000 miles per year in this fine jewel.
15000 / 8 = 1875 gallons for $3750.
15000 / 10 = 1500 gallons for $3000.
Couple of years you'll have your money back.
You could be into this $1500 easy.
I'd guess you are getting 7 to 9 MPG? A 10% improvement would be less than 1 MPG.
Let's pretend you get 8 now and with the new tranny and a wax job you get 10.
And let's pretend it costs $1500 to fix swap and fit that 5 speed, and gas is $2.00 gallon.
The big pretend is you drive 15000 miles per year in this fine jewel.
15000 / 8 = 1875 gallons for $3750.
15000 / 10 = 1500 gallons for $3000.
Couple of years you'll have your money back.
