Running on interstate

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My f-450 with the 7.3 liter and the 5 speed tranny seems to be wound pretty tight when trying to do 70 on the interstate. My tach isnt working but the engine seems to be reved mighty high. At 60 - 65 mph its still seems high but is bearable. Has anyone else experienced this? If so was there a fix. Im thinking maybe rearend gears or different gear in tranny. Other than that I got a small leak around the block heater to fix. I got a new block heater but have yet to install it. You think it might be a good I dea to put a little rtv back on the heater before replacing it? Gonna post pics as soon as my decals and ford emblems come in. I painted the bed,cab, the chasis, and also the rims.Its looking great. I have mounted my welder,my toolboxes, and my ox.acc tanks also. Just a few more loose ends to tie up and Im ready to hit the road with her I think. Thanks for the help.

 

[69oiler]

at 70 with 5.13 gears you are right up against the governor. used to run a 450 with the 5 speed a lot and freeway speeds were a bear. i think 70-75 was the absolute max i could do and it was screaming. which is fine, the IDIs can take it.

rear gear change or aux OD are your options. maybe 4.11 gears would help you out without sacrificing too much power.

 

[Mr_Roboto]

The 450's have higher gears because they are made to pull very heavy loads. If you don't need the full load capacity, you can switch to higher gears in the rear axle. 4.11 is probably as low as you cna go with your carrier.

 

[adrianspeeder]

What is the axle code from the door jam sticker?

Adrianspeeder

 

[94f450sd]

there were only 2 gears available for the 450s.5.13 or 4.XX,i forgot what the 4.xx was i know you couldnt get 4.11 i think it was 4.72 or something like that.i can take my IDI up over 100MPH with 5.13 gears but she is screaming at those speeds.55-60MPH tops for fuel mileage.

 

[towcat]

there were only 2 gears available for the 450s.5.13 or 4.XX,i forgot what the 4.xx was i know you couldnt get 4.11 i think it was 4.72 or something like that.i can take my IDI up over 100MPH with 5.13 gears but she is screaming at those speeds.55-60MPH tops for fuel mileage.

4.56 is the number. anything smaller numerically, you will need a new carrier or even a new case. the offset is different. I've looked into it and backed off due to the cost.

 

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Thanks for the replies and the good info. Glad to know Its not out of the ordinary. Guess I'll keep it in the 60's and plug along. Just have to leave 10 minutes earlier.