how well does the 6 speed manual hold up?

JDPlowboy

JDPlowboy

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Nov 3, 2008
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Ok i have had a cummins for the past 3 years and i am past the point of fixing it all the time!! once i put a chip and a good set of injectors and clutch in it i started shelling trannys! every month! and that adds up quick! so now i am hopefully on the right track of buying a "good" truck now! Half of my buddies say that an automatic is the way to go in a chevrolet because they have more power are quicker and stouter than a manual because they are weak and break. But in the back of my head i am always thinking manual is the way to go because its cheap to get them to hold a little more power! And gear to gear is the strongest you can get!. But! i dont want to be shelling out a 6 speed beacuse i have heard they are high to work on! So i was just wondering if anybody out there can give me some information?
 
Depending on what year your looking for Chebby stoped putting manual trans behind the D max's.... I would guess it may be hard to find a manual trans D max as well as most even in the early years were built with auto's when I was looking for trucks I never saw a manual trans truck on a dealer lot. My left leg has never been lazy so I prefer a manual also but with the D max you might as well just get the auto it is a nice package and will propably hold up better in the long run.

IKE
 
ZF6 trucks are very hard to find, and they are only offered on LB7 and LLY trucks. The 07 LBZ you could not get a ZF6 as the allison holds the power better and is more dependable anyway.

Your best bet is to hit Ebay and check for 01-06 Lb7 and LLY trucks. The 06 LLY is really just a detuned LBZ they are indentical minus the tuning they recisved form the factory.

If your into the big power you will need to spend some money to get the Allison up to snuff. Mine has been holding a 250+ horse tune now for aboput 2 years but I am sure it will give up anyday now. You can expect to shell 2200-3000 bucks for the parts it takes to make you a strong Allison but once you do it it will be ready for a long life of ass kickings.
 
The zf will hold more than you can throw at it. And the Allison is not more dependable than the zf.
 
stock turbo? and your blowing up the nv4500? swap it to a 5600 and be done with it.

maybe consider proper trans warm up. yes. a manual should be warm before you bang gears or get on the throttle hard.
 
JasonCzerak said:
stock turbo? and your blowing up the nv4500? swap it to a 5600 and be done with it.

maybe consider proper trans warm up. yes. a manual should be warm before you bang gears or get on the throttle hard.
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anything that is auto/truck related should be handled as such..

not doing such is asking for a shorted service life
 
malibu795 said:
anything that is auto/truck related should be handled as such..

not doing such is asking for a shorted service life
Click to expand...

exactly. I find it hard to believe this guy is breaking nv4500's left and right with a stock turbo and making no more then what 400hp maybe 450?

If I'm doing my injector size conversion, your injectors are huge, but you lack pump and turbo to really use them (based on what's in your sig)... so you have a hit of power for a second then it falls off.

I'd claim operator error mostly. There are local trucks that have 550-650, and I don't hear them 4500 breaking to often. There's one guy that seems to break them, but he sprays a lot (and did 885 in 4th/1:1). But the lower hp guys seem to have zero issues.

What exactly is breaking in your trans guy? syncro's? gears? barrings? shafts?

My avatar is unique-ish... it broke with out shifting, just rolling on the throttle, but that gear was 117,000 miles old..... The second one had to have been part defect. 15,000 miles later, is broke a few more teeth off.. Granted bigger trans (5600).

And you have a rather light truck too.... So what gives?
 
Dmaxaholic said:
The zf will hold more than you can throw at it. And the Allison is not more dependable than the zf.
Click to expand...

From our experience the Allison will hold more and be more dependable than the ZF's once they are fully built, the ZF IS stronger out of the box the than the Alli and cheaper with a SB clutch or clutch of the like. But I will bet you can make an Allison last longer than any ZF under high HP numbers
 
That's why all the high hp Duramaxs are going to a duraflite. And the only zf breakage I have heard about is guys pulling on the high side and breaking the output shaft.
 
I wasnt aware "ALL" the high hp dmaxes have gone to duraflights? Last I checked there but a handfull. Buck and Ken are 2 I know of off the top of my head. Casper is runnin just as much power as those two trucks and he is still on a Mike L. Allison...

What was the last handshaker dmax to hit a low 10??? I love the handshakers but the Alli can dish it out just as well
 
JasonCzerak said:
exactly. I find it hard to believe this guy is breaking nv4500's left and right with a stock turbo and making no more then what 400hp maybe 450?

If I'm doing my injector size conversion, your injectors are huge, but you lack pump and turbo to really use them (based on what's in your sig)... so you have a hit of power for a second then it falls off.

I'd claim operator error mostly. There are local trucks that have 550-650, and I don't hear them 4500 breaking to often. There's one guy that seems to break them, but he sprays a lot (and did 885 in 4th/1:1). But the lower hp guys seem to have zero issues.

What exactly is breaking in your trans guy? syncro's? gears? barrings? shafts?

My avatar is unique-ish... it broke with out shifting, just rolling on the throttle, but that gear was 117,000 miles old..... The second one had to have been part defect. 15,000 miles later, is broke a few more teeth off.. Granted bigger trans (5600).

And you have a rather light truck too.... So what gives?
Click to expand...

Over fueled stock turbo truck CAN be dangerous in some peoples hands.... I have seen several 5 speeds tore up from instant turbo spool.....sudden impact on gears is not good. I have seen mostly inputs,3rd,5th gear failures.

You can drive with tons of power but you have to learn to drive again; get things rolling,start to spool, roll on into it.

I have seen several 6spd not take much hp to break if driven wrong

IKE
 
I'm not saying the Allison is crap. It's just no one has made the huge hp leap with a zf. And really the op wanted to know about the zf not the Allison.
 
sledshaker said:
what were you shelling out on the trannys?
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I have broke every single part new in the nv4500 top and bottom shafts and every gear, it was just never ending the most i had broke was 3rd gear and bottom shafts i got a lot of those laying around in pieces
 
JasonCzerak said:
exactly. I find it hard to believe this guy is breaking nv4500's left and right with a stock turbo and making no more then what 400hp maybe 450?

If I'm doing my injector size conversion, your injectors are huge, but you lack pump and turbo to really use them (based on what's in your sig)... so you have a hit of power for a second then it falls off.

I'd claim operator error mostly. There are local trucks that have 550-650, and I don't hear them 4500 breaking to often. There's one guy that seems to break them, but he sprays a lot (and did 885 in 4th/1:1). But the lower hp guys seem to have zero issues.

What exactly is breaking in your trans guy? syncro's? gears? barrings? shafts?

My avatar is unique-ish... it broke with out shifting, just rolling on the throttle, but that gear was 117,000 miles old..... The second one had to have been part defect. 15,000 miles later, is broke a few more teeth off.. Granted bigger trans (5600).

And you have a rather light truck too.... So what gives?
Click to expand...

If you dont believe me read up on some of my old posts over in the cummins sections... smokin s on here did most the work! and it would happen most of the time when i would shift to 3rd and roll into it it would just strip 3rd gear clean. i even broke a billet 1-3/8's shaft. I know it is hard to believe but i seriously have no luck with this dang thing! And i dont like tooting my own horn about my truck. It never had a sniff of spray ran through it. I even bought a brand new supposedly heavy duty nv4500 from midwest transmission in zumbrota and i still shelled that thing out!
 
IKNOWEVERYTHING said:
Over fueled stock turbo truck CAN be dangerous in some peoples hands.... I have seen several 5 speeds tore up from instant turbo spool.....sudden impact on gears is not good. I have seen mostly inputs,3rd,5th gear failures.

You can drive with tons of power but you have to learn to drive again; get things rolling,start to spool, roll on into it.

I have seen several 6spd not take much hp to break if driven wrong

IKE
Click to expand...


Thanks for agreeing with me! And yes i had drove it hard i mean thats why we build them fast right? haha
 
Well, a NV4500 can hold 1k hp so Im gonna attribute your failures to driver error.

You could have had a bad case or bad t case to trans adapter.

Those are the only 3 options.
 
Why i am wondering if a zf will hold up is beacuse i found a 06 6 speed and i just want to have better luck with it than my dodge.. I am more of a manual guy myself, But in when your going through gates and stuff a automatic would be nice because parking gear will always be there! I have heard once you get a good clutch in front of a zf and throw away that dumb dual mass flywheel that they make a great tranny. My buddy has an 04 with a dual disk southbend in front of it and he hasnt had any trouble and i knew a guy that had a 6 speed duramax and it was the fastest around my parts and he would bang gears and give it all she had and he never had trouble with it. I just wanted to extended my question to get a better idea.
 
Im planning on installing one in my red truck with cryro'd parts. They seem to be very tough.
 
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