If I buy a pump that comes with the pulley, does it matter if I buy a 17mm or 18mm?

I have the 4.7 in my truck, and I've heard I could have either size in there, but I want to order the part before I start the job, not wait until I get the old pump out to see which one is on there.

Thanks.

 

C'mon somebody must have an idea of this? I know if I was planning on re-using my pulley I would have to get the pump with the same size shaft, but if the pump comes with the pulley will the shaft size matter?

Will both the 17mm and 18mm pumps bolt up the same to a 4.7?

 

What does rockauto.com list as your needed part?

Dakmm

You should list your truck info that helps us to help you. In your user control panel you can insert that info and it will show up on all your posts.

Very helpful when asking questions

 

if concerned buy both at same time they arent very expensive I just grabed one for $12 better quality than my old part anyway.

 

The Pully is what I was talking about get a new one with the new pump.

 

98DAKAZ, sorry, I thought I put my truck info in, I'll fix that. Anyway it's a 2004 Dakota SXT QC, with the 4.7 and Auto trans.

Rock Auto shows both the 17mm and 18mm, like all other parts stores, which is my problem. But they have an 18mm one that comes with the pulley, so if the only difference is the pulley shaft size, it shouldn't matter which one I get if I'm gonna get it with the pulley, correct, unless the 17 and 18 bolt up differently for some reason.

I'm talking about the whole pump here, not just the pulley, so buying two would be like spending $300. I don't want to deal with re-using the old pulley, I've had too many hassles with pulling old pressed and rusted pulley's, the damn lip of the pulley always breaks. I'd rather buy one with a pulley on it, but the 18 is the only one that comes with a pulley, at least on rock auto.

If they bolt up the same and the pulley's are the same diameter, I couldn't care less what size the shaft is. Why the hell are there 2 different sizes anyway, is it just to make people nuts, like most things on cars?

 

Only thing I can say is buy it at the local auto store if not sure see if it matches your pump install, if it works great I dont think the shaft size maters its the shaft.

If you can take your old pump with you to the store they can match it for you.

 

I need to have the new one before I pull the old one out, I can't have the truck down for too long. Was hoping to order from rock auto since their prices are so much better, but the better bet might be to just buy local for this job.

Do you know if there is a difference in pulley size between the 17 and 18, or is it just the shaft, meaning the inside diameter of the pulley? If it's just the shaft I don't care if I put in a 17 or 18, as long as it bolts in and works.

Thanks.

 

I understand it’s hard for me also some work is very difficult I don’t have someone to give me rides to the store for parts swapping i have had to bike to the store a few times.

Same with rockauto prices are better but with a problem like yours buying local is better easy to return parts if you get the wrong part or need other parts.

As long as both bolt on the same I don’t think it will be a problem.

I looked and on rockauto for a 2004 4.7 and it only shows the 17 mm unit you see a 18 mm unit?

 

If it was me, I'd just order the pump with the pulley and not worry about it. The book doesn't show any difference in installation, nor does it mention 17 or 18mm (at least in the 2000 FSM).

You're buying an assembly, not just a component. More than likely the pump itself was made by a different manufacturer, OE for Dodge.