ZF six speed or Alison transmission

[James S]

Hey Everyone,
Just wondering if there is a difference in power and/or torque with either transmission that comes with the Duramax. I have also read that there is a two to three mile per gallon increase if you go with the ZF six speed manual, as compared with the Alison five-speed automatic. Any comments would be greatly appreciated. I am basing this on a twenty-five hundred, not a thirty-five hundred.

Thanks, James

[Colorado Kid]

Rated Power and Torque are the same for both transmissions: 300HP @3000 RPM, 520 lb-ft @ 1800 RPM.

Fuel economy does seem to slightly favor the ZF. I'm averaging 21 MPG on my 2/3 highway commute by keeping top speed down to 70, with a ZF and 2WD. Your mileage may (in fact WILL) vary.

Buy whichever you want with confidence. They are both very good.

[NutNbutGMC]

^.... If ya' want a truck, get a clutch shifter, if ya' want a fine performing machine to enjoy, and still have a truck, get an Allison.

MPG??? When is everyone gonna' stop whinning over 1 - 3 mpg??? If you want diesel mileage, get a Volkswagon. :D Enough already....
:D ;) tongue.gif tongue.gif

[DieselsRule]

It's all a matter of personal preference and $2400. I chose the ZF-6 cause I felt the Allison was to busy upshifting and downshifting and was way overpriced considering it is pretty much standard. With the ZF-6 my truck basically stays in 6th once there cause it'll pull from 35 - 65 w/o lugging. However this motor loves 5th. If you want a stomp it to the floor land missile go with the Allison cause although it's quick, I can't get through the ZF-6 like I could with my old M22 66 Goat. I think in a quarter mile run the Allison would win hands down but powering through the hills, I'll bet on the ZF especially if your pulling a load. Besides, I think I know what my motor wants a little better than that expensive black box.

[mackin]

Its a matter you'll have to decide. To shift or not. Both are strong pullers that will do the job. No doubt the standard will put more power to the rear wheels. The Allison steals some 60 RWHP. That amount comes with the luxury off getting and putting it in drive and your off. No hassle...... With the stick you got to drive it from start to stop.... Me, I'll take the luxury and make up for lost RWHP with the "JUICE"......
MAC :D :D

[GlenM]

James
If I had to do it over again I would go with the six speed. I lost my Allison last week with 16K on the truck. No prior indication just sprung a massive tranny leak. Don't get me wrong the Allison is so SWEET to drive, but for my commercial purposes I will go six shifter next time. That Allison is quirky as hell, it does things that I never took it back to the dealer for because I just knew they wouldn't be able to repeat it. Did I mention it is all so SWEET to drive. I'm sure mine was the exception but I have seen other people on the board who have had their Allisons replaced also. Did I mention the Allison is so SWEET to drive. Bottom Line - You'll drive the Allison and immediately fall in love with it and probably buy it. I just can't afford down time with the truck at all and I haven't seen any posts with six speed problems yet. I know Allison's reputation is second to none but in MY CASE and in this application I'm not impressed so far as to its reliability. Reliability and reputation of the Allison is what made be go with this truck it in the first place.

GlnM

[dmaxstu]

In one of the above posts it mentions the price of the Alison at $2400 and I have seen sticker prices like that on other Dmaxes. I'm sitting here looking at the sticker that came of my 2002 and the MSRP is only $1200 and I paid invoice and it shows as $1032. I'd like for someone in the know tell us why the discrepancy. Stu

[Wally]

Dmaxstu,
You obviously bought the SLT equipped truck. At this option level the automatic is standard and you only payed the difference between the 4L80E and the Allison. The 2400 dollar price comes from the option package that does not include the Auto as "standard".

[Big O]

dmaxstu---IIRC the basic GMC/Duramax price is about $1200 HIGHER than the Chev/Duramax price. But the GMC only charges $1200 more for the Allison, where the Chevy charges $2400 extra. Bottom Line--SAME $$ :D :D

[SoCalDMAX]

James S,

The ultimate decision is up to you. I don't tow anything yet, will never do so commercially and I have the Allison. I think it's great to be able to tear thru congested traffic steering with one hand and not having to shift.

Both trannies are excellent, but you'll lose just a bit more power and mileage with the Allison, not that it's enough to tip the scales. It depends entirely upon your application and what you prefer. There are definite strengths to both transmissions.

If you just can't decide, buy 2 trucks, one with each tranny and drive the one that you're in the mood for that day. ;)

Regards, Steve

[NutNbutGMC]

Quote:
I think it's great to be able to tear thru congested traffic steering with one hand and not having to shift.
__________________________________________________ _______________________

^......I like this guy !!! :D And he is oh, so correct. But each to their own. I say buy two of 'em, also......

[mackin]

I feel for the grievance some are suffering on the disappointments on the Allison. I do think the failure rate is mentionable but, I think there has been only 2 or 3 out of a whole lot running here a very small percentage, not enough to shy away from the purchase. It's quirky at times, but rugged and Heavy Duty. Some minor problems were addressed with TCM updates. If you like to; drink coffee, tune the radio, talk on the cell phone, take notes, eat, smoke, scratch an itch, go with the Allison I did runs great. If buying two is not an option. LOL


All the things they do in Calif. Traffic LOL


One thing for sure SoCalDMAX knows traffic.......If you've ever been to California traffic is some crazy 6+ lanes of maniacs. Two lanes coned off (Fast Track), That you have to pay a premium to drive in ...... Buy a Motorcycle and weave........Hope no one opens a car door to dump out their coffee or empty their ashtray......LOL
MAC :D :D

[ 04-11-2002: Message edited by: mackin ]</p>

[1BADDMAX]

I love the 6 speed. I get 18-20mpg in the city and about 20-22mpg or greater on the highway. I can leave it in 6th gear down to about 35mph. I couldn't see spending $2200 on an automatic tranny even if it was an Allison. I have been on the highway in heavy traffic and just put it in Granny and let it creep.

[Colorado Kid]

dmaxstu,

On your sticker is shows $1200 for the Allison, but on my sticker it shows $1095 credit for the ZF. That's why I say the ZF cost $2,300 less than the Allison. smile.gif

[Timberline]

If you will be in a lot of traffic most of the time then get the Allison. The Allison will also be quicker off the line because of quicker shifts. I seriously doubt that you would ever see the power difference between the two transmissions.

Which ever transmission you chose it will be the right one because you can't go wrong with either one.

I personally have the ZF-6 and LOVE it! but there have been times when I wished it was an Allison. As you can see by my signature I prefer to pick the gear that I think is best.

[DmaxMaverick]

Colorado Kid

The difference in price, in your case, is not $2300. It is $1095. An upgrade from the ZF is $1200. If the allison is included in the trim level you ordered on your truck (or was delivered with to the dealer), and you downgrade the tranny, the difference is $1095 (credit). It would seem that keeping the Allison in the trim package would save $105 compared to a standard ZF to Allison upgrade.

[Colorado Kid]

Uh, NO! When I was specing my truck the only two transmission choices for the D-max were:
ML6 6-Speed Manual - Invoice ($ 941.70) - MSRP ($ 1095)
or
M74 5-Speed Automatic - Invoice $ 1,032.00 - MSRP $ 1,200

So neither trans was "included" in my SLE. If I had stayed with the "included" 6.0L I could have kept the "included" 4L80-E (aka MT1) or chosen the NV 4500 (aka MW3) for the same credit amount as the ML6.

So Allison is $2,295.00 higher MSRP than ZF-6, or $ 1,973.70 higher on invoice.

If I add the 2% I paid over invoice and the 2.9% Sales tax then the choice I made was $2,071.56 less than the other alternative which is $39.95 per month (for 60 months at 5.9%) that I can spend for more fun time in the truck. :D

[Jelisfc]

I just visited GM Buypower and CO Kid is right. There is a $2295.00 difference between a ZF and Allison.

The Allison is one tough tranny and I've driven many different heavy trucks and military tracked vehicles to include an all wheel drive Freightliner semi tractor with a 400 Hp Series 60 and 4 spd Allison pulling a D7G cat on the back through snow, mud, and sand. The transmission is THE reason those vehicles can do some of the stuff they can.

My 2 cents. I'll be buying a 2500HD CC 8.1/ZF in the near future. The Allison is too expensive an option and sucks up too many Hp for me considering I've driven manuals for 20 years.

[mark45678]

Ok I think the real problem is that you guys didnt take into this equation that some trucks have base model trim and some are up grades.... up grades came auto with the 6.0 ,base came with 6.0 and a nv4500 5speed.... then you add in 6.6/8.1 and you have 2 choices auto,stick? its gets a little confuseing but I think this is where things dont make sence! its like the 6.5 td option in a 1/2 ton almost 3k or in a heavy spec 3/4 the 6.5td was 1850!

[needbigtruck]

Bottom line, there is a price difference, the auto uses more fuel hence the transmission cooler to remove it's heat, the 6 speed gets better mileage, in heavy traffic the auto is nicer, control of the truck (in snow or going up or down hills) is better with the 6 speed. I like to shift. Period it's all personell preference.

[DMAXDiva]

The truck I ordered back in January had the ZF6 (2500,LS,4x4,CC,SB), but since the dealer botched the order (that's another story entirely!), I bought a D/A off another dealer's lot and have not regretted the purchase for one second. This Allison is amazing, and with every passing mile my smile widens :D I love this truck!!!

My husband and I pulled our 25ft center console bay boat to Lake Livingston yesterday and could not have been more pleased with the performance of the truck, especially the Allison...love that tow/haul mode!

Besides, if the urge to manually shift gears completely overtakes me (which hasn't happened yet), I can always hop in my old '94 Cummins 5spd... ;)

[srubrn]

Just don't expect to box a performance box for the ZF, to my knowledge nothing works well with it. My Dynomite box is very qwerky at times. JK tells me VA is working it out though. Juice don't work with it either.

[sumday_a_dmax]

shifting is for the birds.

guys who have to have that "extra control" of manually shifting need to be in therapy.

don't behave like a lower primate, get the allison.

[Big O]

sumday_a_dmax
Contributor
posted 04-16-2002 02:21 AM
--------------------------------------------------------------------------------
shifting is for the birds.
guys who have to have that "extra control" of manually shifting need to be in therapy.

don't behave like a lower primate, get the allison.
--------------------------------------------------Don't get me wrong, I think the Allison is the best auto made, But I also think the ZF6 is the best manual made. Different strokes for different folks. Maybe some prefer the traditional manuel, maybe some think the less 'gadgets', the less to break. Some may think that newer is not necessarly better. Some might think that only lazy men use auto's and that a really 'working' truck uses a manual. Who is right and how is wrong. I wish I had both. The Allison to 'play', and the ZF6 for work; but since I could barely afford one, I choose the XF6. My .02$

[ 04-16-2002: Message edited by: Big O ]</p>

[gun runner]

I have to agree with Dieselsrule. If your going to do serious towing over 13000 lbs. gross; 6-sp is better. The auto shifts too much up and down every time you go over an overpass.

[1BADDMAX]

I'm glad I got the manual tranny. I had been driving Auto's since I was 16 (learned to drive on a stick, though). After all the problems I've seen with the Allison I'm glad I got what I did and saved $2295 too! I got tired of the shift busyness of the autos. Don't get me wrong I liked the 8.1 and Allison combo I drove, but it just wasn't for me. I think it is hilarious to see all these guys changing their ATF and filter when I don't even have to worry about that. I will probably change mine when the truck hits 50k. Enough ranting......

[slapshot44]

If you're going to bash the Allison, at least use specifics, not generalizations.

The shift busyness is a non-issue. I had it, I had the computer reflashed, no more shift-busyness. If you don't want the transmission deciding when to shift the truck, then by all means get the manual. After all, the definition of an automatic transmission is that it "automatically" shifts gears for you.

What is so hilarious about changing tranny fluid in an auto versus a manual? If I remember right, my auto doesn't need a fluid change until 50k either...

The only other problems that I can remember off the top of my head are fluid leaks that have been the result of improper installation of the torque converter and some bad shift solenoids? When a quirk is pointed out in the programming, there seems to be an update available soon after to address it. There are a few people who have continued problems with their Allison (there are a few open threads right now), but there are going to be a few "problem children" with any mechanical device. Just look at what Bearman went through with his first truck. If you generalized his problems to all of our trucks, no one would be driving one. But he seems to be extremely pleased with his new Dmax. From what I've seen, the Allison seems to be well under the statistical baseline for product failure.

So, as it has been said, enough ranting. The thing that sets this board apart from all of the "other" ones is that the people on this one don't bash others for their choices. State your opinion about what you like or don't like, don't generalize and inflate a very few problems into the norm. Both trannys that we have a choice of are the best in their respective fields at this time. Read all the pros and cons on both types and choose what works best for your situation.

[mackey_62]

I've had my ZF for almost 3 months now no complaints period! Believe me you don't have to shift this truck that much. My 2000 3/4t 6.0 needed torque converter at 25000 mi. This was my third auto in a row with tranny problems. I buy new to avoid these problems. I think this Allison needs a couple more years before we can call it "bulletproof". Maybe Allison next time.
I'm sure 2002 is better than 2001, and 2003 will be better yet. My 2 cents, buy Allison with 98% confidence, ZF with 100% confidence.

[RealBigTruck]

I just test drove both for the first time. I stepped up from an old Ford F350 turbodiesel (IDI, not powerstroke) with an E4OD automatic. That tranny sucked for the power of the IDI motor. And it started slipping. There was more. The auto was just a headache to me and I was alway waiting for it to break into pieces.

So I drove both a base model Duramax crew cab with ZF-6, just to see what the manual felt like in a big truck, and I drove an SLE Duramax crew cab with the Allison.

The ZF-6 was tricky to get right. The shifter is balky and the clutch has a wierd release at the bottom of the stroke so it's easier to hold the clutch all the way down. So the clutch tension changes through the stroke of the pedal. Wierd.

I drove the Allison and was very impressed. Compared to my old E4OD, it was awesome. Seemed to have so many gears in there. The tow/haul mode was pretty cool, too, because it would hold a gear much longer before shifting up, regardless of inputs to the go pedal. Thought it was a worthy automatic.

I ultimately went with the ZF-6. I grew up shifting cars and it seems "right" to me. Also, there will always be a question mark in my head about autos. Since most of my truck use is going to be hauling a trailer, I wanted to be the one picking what gear I'd be climbing a hill in. Plus, the manual trannies seem less susceptible to overheating.

So, now that I've driven the ZF-6 for a few days, I'm still glad I got it. BUT, it's definitely not as easy to get around in as the auto. That shifter is moving a lot of big parts to move a big truck. This is definitely not my Mazda Miata's shifter! It takes a little time to get from gate to gate. An Allison would definitely win in an acceleration contest. Also, since I'm still breaking it in, I'm supposed to be starting in 1st (granny gear) to break in the clutch. The 1st to 2nd shift is difficult because of the way the shifter is sprung, and it's easy to miss the 2nd gear gate. But from 2nd gear on, the tranny shifts very nice, if a little stiff. I've learned on this site that it will loosen up a bit.

Can't wait to tow with this truck!

[ 04-16-2002: Message edited by: RealBigTruck ]</p>

[Jelisfc]

RealBigTruck, you are lucky to find a ZF6 on the lot. I haven't found one on a lot nor the street yet in Mpls/St. Paul. I'll probly by on faith that I want a manual.

[neophyte]

I have driven manuals all my life. Cars, SUV and trucks. The latest I went from '82 Ford F150 to a '98 Chevy 1500 to my '01 2500HD. I gotta admit, shifting was tricky at first. It took some getting used to. However, though it did felt ackward at first, I am thrilled with it. I am glad I stuck with manuals.

[neophyte]

I have driven manuals all my life. Cars, SUV and trucks. The latest I went from '82 Ford F150 to a '98 Chevy 1500 to my '01 2500HD. I gotta admit, shifting was tricky at first. It took some getting used to. However, though it did felt ackward at first, I am thrilled with it. I am glad I stuck with manuals.

[sumday_a_dmax]

as far as "working" goes, no transmission maker has a better working pedagree than allison.

as far as "serious towing" goes, if you are going to haul/tow so much that you think the alli might not take it, maybe you need a c-4500. though i think it to comes with an allison option

[spctr13]

I " think " I have as much experience with the D-Max , ZF-6 combo as anyone out their , and so here goes a few impressions and realities . 48,000 miles in 13 months ,38 states, 3 provences , 1 teritory , 3 corners of the U.S., plus above the Arctic Circle

Just returned from a 7 week 11,000 + mile trip , pulling a 26ft travel trailer . And when I say "just" , that's one hour ago , for the last leg from Wisconsin to Massachusetts . 1130 miles, 18 1/2 hrs including a noontime pass through Chicago . This trip included 280 ft below sea level to 11,313 Monark pass in Colorado . I get 12mpg pulling interstate , 17 and fractions solo interstate logging 72mph for both . I have no problems in trafic , with both Boston and the rest of the East coast as a test . I realy enjoy this peice of equipment .

The bad news : I did have a new transmission put in at 35,900 miles . A noise developed at the last 1-1 1/2 inch of clutch travel , quite loude .Turned out to be a bearing on the input shaft , low cost but GM had no repair parts at that time , so I got a whole new one .

[INDI-GO]

Allison
After 32 years of driving a manual in Houston traffic, I decided to give the ole left leg a rest and go with the Allison. And creepy crawling around the hunting property is wonderful not having to shift, drink coffee and shoot jackrabbits all at the same time.
But, for out on the road I would have liked to had the 6 spd manual. Maybe I will just get another one as suggested. :rolleyes:

[Timberline]

RealBigTruck
If you think you like the ZF-6 when the truck is empty you will really love it with a load. The 3500 and ZF-6 was definitely designed for work. The whole truck will feels smoother with a load on it. Your shifts will become even better and it will shift more like your Miata with a load on it.
I have no regrets in getting the ZF-6 and like BigO said I wish I could have both the Allison and the ZF-6.

[srubrn]

Got the six speed and love it!! But shouldn't reverse be under sixth gear? Find myself starting off in reverse alot. I never lauch from a stop light because I might be lauching backwards. Had the truck since Dec. and still get it confused. Also it hauls, throw her in six and set the cruise and let her go, even with a 32ft fifth wheel.

[HotShot]

If I had another chance I would get the ZF6 again but I'm a little biased. I learned to drive in a 4 gear Road Runner. If my wife could learn to drive a stick her Cutlass would get a 5 or 6 speed but alas that is only a dream. I enjoy rowing gears even here in the city. The two biggest advantages I find are that if you get crooked you just hit the clutch and straighten up right away and using 2nd or 3rd gear to get unstuck when 1st instantly spins the tires in the mud or snow. If there was a forced second gear in the Allison (like the C-4 or C-6) I would have considered it because I am use to popping an autobox into nuetral without worrying about catching rewind.

As far as cost goes, what I saved buying the ZF I will probably spend in clutches because of the high milage I put on (already have 120,000km in 11 months).

As far as service goes the ZF is considered filled for life but I service mine anyways because of the high milage. The Allison needs fluid and filters regularly.

As far as reliability, I never heard of any ZF failures till this post (I haven't been on the Drivetrain forum since Jan.) but have personally met 2 people with Allison failures. But the ratio between sticks and autos is pretty extreme so we're likely to here about the Allison a lot more even if the reliability is the same.

Your money, your choice. There is definetly enough info and opinions around here you should be able to make an informed choice and know how to take care of the new toy. Either one will give you a silly grin every time you even think about driving your truck. Have they got a recall for that goofy grin yet? :D

[ 04-17-2002: Message edited by: HotShot ]</p>

[sumday_a_dmax]

...savages

[Kansas Kid]

Well, us guys that like the ZF over the Allison may be savages and need therapy but atleast we aren't lazy and are smart enough to decide which gear the truck needs to be in. ;) (no offense to you guys that have the Allison, but somebody here seems to have a problem)

I say drive them both if possible, and pick which one fits your needs best. But the general opinion between people who own the Duramax with both transmissions is that the ZF will perform better when loaded.

I can honestly say that I was unimpressed with every Dmax/Allison truck I drove, even when loaded. The tranny seemed to be holding the engine back and would not let it work at the lower rpm. I would buy a PSD over a Dmax/Allison from my experience with them. But there is no way I would buy a PSD over a Dmax/ZF. I loved the way that combo drove.

[ 04-18-2002: Message edited by: Kansas Kid ]</p>

[gregmican]

I love my Zf-6 speed, but then again I like to shift. Although sometimes when Im in Houston I wish I had the Allison.

[trailguide2u]

Jelisfc--If you want to drive my ZF(which I love)
email me. I work in St.Paul
zrartiecat@hotmail.com