[Steven Bonin]

I just bought a 96 f350 5 speed 7.3. At 70 its running 3200 rpm. Is this the rearend or a bad turbo

 

[Tiger02]

I somehow missed the 5 speed, so my reply was way off.

 

[Steven Bonin]

I have a check engine light on but oriellys said no codes

 

[Steven Bonin]

Sorry i forgot to add its a 5 speed manual

 

[bugman]

First off you are going to have to know what rear end gears that you have. There is a tag on the rear end housing that will tell you if you know how to read it. Other than that there is a sticker on the door panel that will have the code, then you can go here to find out what it is.

If you have 3:55's then the RPM's are high but if you have 4:30's then they are about right.

As for the CEL 99% of the auto part stores can not read the codes from a Ford diesel with the code readers that they have. They have to have one that will read Ford propriety codes.

 

[madpogue]

There were no 4.30s.

Is this a pickup or C&C?

By definition it's not the turbo. RPM/speed ratio is determined by transmission and diff ratios, and by tire size. Have you checked the speed against a GPS?

The FLAPS cannot obtain diagnostic codes from our trucks. You need a device that understands the "Ford Enhanced" protocol.

 

[Patrick Feeley]

Just for reference, my 94 with 4.10's and 5-speed used to run about 2550 rpm at 70 mph (with 235-16 tires). Cheers!

 

[mulescj8]

My 97 has 4:10s and runs about 2700 to 2800 rpms running 70mph with 235/75/16 tires