I am in the process of ordering a new 2500HD SBCC 4x4 with the Dmax/ZF combo. My intended uses for this truck are to pull my 2-place snowmobile trailer(2,000# loaded) or my 31' fifth wheel(8,500# loaded).


I am not into the racing/pulling game. Truck will be left stock.


Should I have any concerns with the ZF6 based on my intended use.


Thanks,


Kyle

30cal4me


Welcome to the forum. I have 92k on my stock '02 ZF and going in for my second DMF failure. If the new DMF fixes the problem, then you will have a very dependable rig.


MaxRock

I get the impression that many people think there is a problem with the transmission in the GM trucks. The problem is not the transmission, but rather the clutch and flywheel.


Hey GM, some of us like to shift our own gears! How about fixing the flywheel and hard clutch issues for us.

ZF is really strong. I'm putting 1100# ft through it with no problem. Just don't use power adders and you'll be fine with the DMF. The best fix for the problem is a solid flywheel.

I am in the process of ordering a new 2500HD SBCC 4x4 with the Dmax/ZF combo. My intended uses for this truck are to pull my 2-place snowmobile trailer(2,000# loaded) or my 31' fifth wheel(8,500# loaded)

I am not into the racing/pulling game. Truck will be left stock. Should I have any concerns with the ZF6 based on my intended use.


Thanks,


Kyle

If you keep it stock or reasonably stock, you will have not problems as problems that sometimes occur usually happen only when the unit is used well beyond its designed ratings.

I do not know anybody that has not had flywhell trouble with the ZF installation. I got a new part number flywheel installed today and they say it should be the edd of my problems. Alls well now only time will tell. The old ones started making noise about 5,000 miles or so, and I have had quite a few installed. If I had it to do all over again I would have gone with the Allison. I have never had an automatic in my primary driver but have not heard of too many major problems and the shifts positive and at a lower rpm. I don't like the shift pattern and "feel" of the ZF gates.

I do not know anybody that has not had flywhell trouble with the ZF installation. I got a new part number flywheel installed today and they say it should be the edd of my problems. Alls well now only time will tell. The old ones started making noise about 5,000 miles or so, and I have had quite a few installed. If I had it to do all over again I would have gone with the Allison. I have never had an automatic in my primary driver but have not heard of too many major problems and the shifts positive and at a lower rpm. I don't like the shift pattern and "feel" of the ZF gates.

The Ally does not have a sterling record either and it remains to be seen how they will hold up long term as they have not been around that long as compared to 4L80'd and such and not much to go wrong with a manual gear box either. Also a "clutch" is a lot cheaper than a Ally rebuilt out of warranty.

If the new flywheel works as advertised, this will be the truck I dreamt of when I bought it 2 years ago. I went with the ZF6 to avoid autotrans problems. Little did I know I'd be on my 4th flywheel in 55k miles. About half of it's life is spent towing a 10k# enclosed trailer. Not modded and not heavy towing.

Gary
Sheehan Motor Racing
www.teamSMR.com

I'm with you, Gary. Love the truck. Love the transmission. If I can just get this flywheel issue sorted out I'll be very happy. And a little more holding power for the clutch, so I can use the juice.

I've been out of touch for awhile. Is the Juice available for the 6 speed?

Gary
Sheehan Motor Racing
www.teamSMR.com

Yes ... actually, it's always worked, there just hasn't been any way to change the power levels unless you put it on an automatic transmission truck. But now they've got this little control box that attaches to it, called the "Attitude". It lets you change power levels on the fly, even on the 6-speed trucks. Also gives you some more control of the low boost fueling curve, so you can trade off responsiveness for smokiness.

I mostly run around at power level 1 or 2 (out of 5) with the low boost fueling set at 4 (out of 5). Makes for a responsive truck that accelerates briskly and effortlessly. Also I find I can pull my trailer up hills in 6th gear with the cruise on at power level 1, downshifting is hardly ever needed. Makes traveling easier.

The only time I reach down and crank it up is when I need to pass on some little 2 lane with limited room. Also when I come across a Ford or Dodge that needs to be humbled http://www.dieselplace.com/forum/smileys/Big Smile.gif ... I've yet to be beat.

For the longest time, I had no trouble with the clutch and the juice. But lately, putting my foot into it in 5th or 6th gear at power levels above about 2 is making the clutch pedal go hard and not want to return off the floor by itself. Hence the new heavy duty clutch going in with the new DMF.

The Attitude controller has some other nice features, too, like monitoring of boost & egt & load & load & throttle position and about a dozen other things, and the ability to defuel on high EGT's. Be aware that it's performance measurement features (0-60, 1/4 mile) don't work with the 6-speed.

Nice! Do you monitor your EGT's as well, or just let the software take care of it for you?

I'll have to look into this!

Gary
Sheehan Motor Racing
www.teamSMR.com

I have a pillar mounted isspro gauge for EGT (as well as boost) so I never bothered installing the Juice's temp probe and I don't use it to monitor EGT at all. I generally leave the display set up to monitor coolant temp ... yeah, it's redundant with the gauge on the dash, but in actuality, it gives a lot more resolution since it's digital, especially at lower temps. Tells me much more accurately when it's worthwhile to turn the heater fan on (about 130). Also, the Juice's power boost doesn't seem to start working until the temp is above 160, and sometimes it's useful to know whether or not you've got the extra power on tap, for example, to make a passing decision.

I also tried the Predator, and it's alright, but it doesn't compare to the Juice. The Juice has a much more refined fueling curve as well as on-the-fly control. I now just use the Predator in it's stock tune setting and use it to correct the speedo for my tires as well as remove the speed limiter. It's also useful as a code reader/diagnostic tool and it can even monitor injector balance rates.So I don't regret buying it, but as a power booster, it doesn't compare to the Juice.

In my experience the tranny is just fine, but the clutch just can't hold up.