gear ration question?

[DIESELMAN7.3]

i got a question.... in my 97 ps when i'm headed down the freeway at round 75 or 80 the rpms are just running really high. if i changed the ring and pinion out i know that will help, but is there anything else i can do. jus wondereing and on these trucks how many rpms are too much??

[overl0rd]

As long as you're not running a chip that removes it, the truck has a speed limiter and governor in it. You can get an auxillary over/under unit, but their durability is up in the air. Its been my experience that the unit turns into the weakest link in the driveline. What kind of revs are you turning at those speeds? In my pickup with 3.54s I turn around 26-2700 or so.

[mschn99]

Originally Posted by DIESELMAN7.3

i got a question.... in my 97 ps when i'm headed down the freeway at round 75 or 80 the rpms are just running really high. if i changed the ring and pinion out i know that will help, but is there anything else i can do. jus wondereing and on these trucks how many rpms are too much??

if its a manual....you could have a custom built trans done.....but more money than a ring and pinion would cost.......other than that.....you are basically limited by the fact that diesels run less RPM's....and only a gear ratio change in the trans or rear end will make it run less.....as overlord asked...what RPM's are you running .....and i curious what gear ratio you have in the rear diff....and also...is your unit 4x4....because you would have to change both ring and pinons if it was........Marc

[mgwerks]

I dunno. Mine's a 3.73 limited slip, and it runs exactly 2,000 RPM at 70 MPH.