Ok ive had my truck about two weeks now....i can speed shift the ZF pretty good now so i can extend the life of my clutch. But when i start out in 1st the engine bogs down to really low rpms...300-400. The engine sounds really bad at those rpms..(hard knocking)..i dont know if its normal for a 7.3w/6spd. Im not dumping the clutch or anything like that... any thoughts?

At what RPMs would be considered lugging a 7.3? Also ive been trying to keep it under 2k (to see what my MPG is)...but im affraid i might carbon it up? Thanks!

 

are you giving it any gas?...doesnt sound like it

 

No...im used to a gasser 360FE and never had to give it gas....i figured since the 7.3 has twice the tq as the 360FE it wouldnt need it?

 

You need a little throttle to get the psd going from a stop. The hard knocking you are hearing is the computer trying to keep the engine at least at the idle rpm. When done occasionally probably isn't a problem, but it causes severe shock to the crankshaft. I don't know from experience with Powerstrokes, but with the Chevy 6.5 turbo diesel they had a problem with breaking the crankshaft behind the manual transmissions when they were lugged too often. I worked with a company that still has about 15 of the chevy diesels and that is what was happening to their rigs. You might want to be careful with lugging to often just to be on the safe side.

 

What you're hearing is "gear rollover" and is normal. Trying to start out without throttle is not helping. Give it some throttle, and ease out the clutch. You make a clutch last by getting it out of gear at the light (some people insist on sitting there in gear with their foot on the clutch... brutal on your throwout bearing) and replacing the factory POS roller pilot bearing with a solid Kevlar bushing.

 

I let my clutch slip at idle just enough to make the engine do that romp romp romp and then by the third or fourth romp the clutch is fully engaged and I give it the go pedal. If I give it too much clutch it does that hard knocking that you mention.
Another thing that helps a lot at low RPM is the HX hose. That really made a lot of difference on my truck.

 

Everything sounds normal. I have 145,000 on my six speed and no problem. I know the guy that had the truck before me and he babied it like an only child, never any hard acceleration and no throttle when letting off the clutch on the line. I currently have no problems and I am loving the six speed. Isn't that thing SWEET!

 

The HX hose is on its way...i got the stainless steel braided one.

Ill experiment with it to get a better feel for it...hopfully i dont destroy it! Thanks for the replys.

Foxracer800...the 6spd is my first OD tranny...and loving every bit of it!

 

Just wait until you hook a load to it and really start pulling. Especially up a hill. It will make your old gassers feel like a Model A.