Axle gearing options

[lkrasner]

I have a 94 short bus conversion (e350 based) with a 7.3 idi and e4OD trans. It feels like it is geared really low to me. No tach to really verify, I need to remidy that... It does 55-60 comfortably, but really struggles much over that, and the engine is screaming in 4th gear. With a diesel, I'm thinking it would actually be happier geared a bit higher to bring down the highway rpm. Does this make sense, or is that just going to make it have a harder time at high speeds?

Can someone point me in the direction of where I should look to determine the current axle gearing, and what would be involved in swapping it?

 

[DaveBen]

Look on the drivers door for a sticker that will show the load capacity and the gear ratio, in code. Post the axle code here and we can tell you the ratio.

 

[IDIBRONCO]

It's possible that it was intended for around town only service so it could be geared really low. I don't know how possible this is, but I just thought I'd throw it out anyway.

 

[lkrasner]

It's possible that it was intended for around town only service so it could be geared really low. I don't know how possible this is, but I just thought I'd throw it out anyway.

That's what I was thinking too, it is a bus afterall.. I've never really even driven another diesel before, so I don't know how it should sound.. Does any one make some kind of cheap temperary tach I could use to check my rpms at least?

 

[IDIBRONCO]

I don't know of any cheap tachs, but hopefully somebody else will have an idea.

 

[The_Josh_Bear]

That's what I was thinking too, it is a bus afterall.. I've never really even driven another diesel before, so I don't know how it should sound.. Does any one make some kind of cheap temperary tach I could use to check my rpms at least?

To put your mind at ease in case high rpms are worrying you-- diesels are governed and can't be over-revved with the go pedal. More importantly they can be run up against the governor all day long without causing significant harm to the engine.
So if you regear it would be for MPGs or less cabin noise or whatever, but it's not really about engine wear.