bandit1trucking

On my '96 3500, I just recently noticed that up thru 3rd gear, it'll rev to, and maintain 3100 RPM's, but in 4th and 5th, I can only get between 2500 to 2700 RPM's. Why would that be on a mechanical pump? I've got a 0 plate, and the starwheel has been turned. It pulls like a freight train, and generally runs good, but I thought this was kind of odd.

Also, I recently replaced the turbo, The original one had been rebuilt about 3 times, and just wouldn't hold together. With the old one, It would peg my 35 psi boost gauge, but my pyrometer would never climb above 1,000 degrees. It seems to pull stronger with the new one (It's supposedly an updated version Holset), I still get around 28 pounds of boost, but you really have to watch the pyro now. The temp starts climbing much quicker than before, and climbs at a faster rate, until you back out of it. Also doesn't seem to have as much whistle as before to the sound (Dual straight stacks, so it's pretty easy to hear.)

1stGen545

its becose there is more load on the engine and you dont have the power at the high rpm to pull 3k. mine would not do it. They start to defuel at the top end and just dont have the fuel to do it. I put my 4K gsk in now when I get to 2800 or so where it use to fall off now it is just getting started but the egt's will peg past 1600* in just a few seconds even with 40psi boost from an HX-40. every thing sounds like your truck is doing just as it should but what is your new turbo. You should have had a HX35-12cm stock.

bandit1trucking

It's just a brand new HX35-W. The only difference I physically saw between the old 35 and the new one, is the new one has a port on the compressor side, for the wastegate hose to hook to, instead of using the factory hose. I have considered a 3K gsk, just to give it a little more top end, but I'm also thinking about swapping the gears (it's got 4.10's). I think I'd still have plenty of power with 3.55's (that's what the '99 and '03 both have) and it would help my mileage some. It's got lots of torque, we had to get a new clutch for it, because I could break the clutch loose in 3rd, 4th and 5th empty, and you couldn't hardly pull a backhoe at all without smoking the clutch. Before the pump adjustments, the clutch never slipped. I bought it brand new, and it's only got 94,000 original miles, so I plan on keeping it going for a long time.

1stGen545

I would definitely go with the 3.54's.