ZF 6 speed with 8.1L or Duramax

gmguy · November 28, 2002

I am looking for information regarding the 6 speed ZF and maybe the 5 speed ZF. I am thinking of buying a 2500HD with a stick for mainly gas mileage reasons, but also cost. I could save $2000 to get one of the engines I want and wonder if its worth it? I have driven several sticks and because I am not finding any on the new car lots, am wondering if this should be pursueable?

Roofer · November 28, 2002

Welcome to the site!

I think you are right about availability. I have yet to see a manual HD. I'm not sure if you can even get a 8.1 with a manual. I don't think it would gain all that much for fuel mileage, but some probably. I'm sure the 6speed is the only option besides the Allisson.

DigUout · November 28, 2002

The 6 speed Dmax is kind of a Unicorn right now. I've seen one in the last 8 months on our lot and it sat for quite awhile before we dealer traded it. The gas mileage difference might be about 1 MPG. I haven't seen any 8.1's with a manual.

Looking down the road when you go to trade it in or sell it, you'd be better off with the Allison, as that is what everyone wants. Also GM has a manufacturing issue with all manuals right now. I've just ordered a manual 1500 for a customer and we're not sure when we'll get in. Not sure if its a workers issue or product deficiencey, but production of all manual GMC's has come to a halt.

If you need to save the $2K, take the rebate. You could also tell your dealer the guy down the street will sell it to you for invoice. This time of the year I can almost guarentee they'll step up and slash the price for you. Good luck -

CMNTMXR81 · November 29, 2002

Do you want to upgrade to the LS or LT trim package with split buckets and full length center console?

If yes, then you cannot get the 6 speed manual with either the D-Max or Allison.

gmguy · November 30, 2002

Thank you so much! I didn't know about the availability problem. Based on that, I won't even pursue the stick. I am not very concerned with resale as I will likely keep this for 100-150K miles. If getting a stick, I would get a base model.

If a stick is not available, I will now be looking for an LS or LT, as they have the good radio available now. I have a '96 Z28 with a Bose in it and absolutely love it. Although, I'm also looking to trade that one for a 2002. Difficult to do in winter.

CMNTMXR81 · November 30, 2002

I do believe though that you can still get an LS trim truck with the 60/40 split bench which will then allow the availability of the 6 spd manual.

You just can't do it on either LS or LT trim when you get the full center console and buckets.

I'd love to have the 6spd with my LT trim...D*mn that'd be awesome, but I wanted the luxury more.

lakerunner · December 2, 2002

Must soccer moms can't drive a manual transmission. GM knows what side their breads buttered on.

Looked for two months before buying 2500hd crew cab with a juicer. ???

Colorado Kid · December 5, 2002

I orderred mine and waited, It only took about 7 weeks.

When it was new it was very notchy, and the clutch has a spring that goes over center...when the pedal is all the way down the sprong is helping you push, when it is all the way up it holds the pedal against the stop. This took a little getting used to as the spring kind of kicks you just as the clutch is starting to bite, and you lurch off like a 15 year old. I think the engagement hs gotten smoother and I know the shifter has smoothed out a bunch with a few miles...now if I let someone new drive it they don't have much trouble.

Mine is 2WD and with the 6 speed I never get less than 20 MPG unless I'm towing something. I can e-mail you a spread sheet with complete records to date, if you care.

If I couldn't have saved the difference between the Allison and the 6 speed (and between 4WD and 2WD) I wouldn't have been able to swing the price of the truck, and I LOVE the truck, so I have no regrets. Otherwise I would have been in a 2WD 1500 Extra Cab with a 4800 and 5 speed... my kids would hate me and I wouldn't be towing the 5th wheel. I did seriously consider a 2500HD Crew Cab with the 6.0L and 5 speed, but decided the D-max was what I really wanted, and I could make up for the price difference by owning it longer and burning less fuel.

By the way, the minivan driving soccer mom in my family likes my truck a lot, and if it had an Allison I think she'd have sold her Honda Odyssey and stolen it from me by now, leaviong me to drive the old '91 until the wheels fell off or I bought her a Suburban (actualy a Yukon XL to fit in around here) ...but she won't let me buy the Sub/Yuk unless it has a D-max...that and I don't have the $$$$$. I guess it's a good thing I got a 6 speed!

jelisfc · December 5, 2002

I totally agree with Co Kid. I ordered my '03 GMC 4x4 Dmax/ZF CC, SB on Sept 19th. I picked it up Oct 30th. One day short of 6 weeks. The dealer was a small town guy with no allocation. It's an SLE, cloth 40/20/40 bench seat. Crewcab was a must and a 6.0 was not an option for me. I wanted a manual and the fact the Alli costs 2K more made up my mind even more. I thought long and hard between an 8.1/ZF and a dmax/ZF. I drove both with allisons. Never saw a ZF in the flesh until I saw mine. No regrets. I only keep vehicles for 3-4 years 60K to 80K miles. My calculated breakeven is somewhere in that same range.

The final deciding factor for me was longer distance between fillups. My parents live 300 miles away and it's bad enough stopping at McD's for the kids much less a second time for gas with an 8.1. I told the wife. We'll pay the same amount of money in the end so we are going for the dmax.

At 2000 miles the trans is well broke in and easy to drive. I don't have a clutch issue like Co Kid. Maybe something changed in the 2003's. I will say it's a short engagement range so you can't really slip the clutch. It's all or nothing. I like it now. It reminds me of an air operated clutch some semi's have. I get 19-20 mpg with straight #2 and am getting about 1 mpg less winter blend highway. My overall average today is 18.7 mpg almost no towing.

I too have a minivan driving wife. She drove my truck right away before the trans was broke in. Killed it once, spun the tires the next time but hey she hadn't driven a manual in 6 years. Now that it drives smoother I have complete faith she could do anything except back my enclosed sled trailer.

BDBWTE · December 6, 2002

You know some people don't like putting up with the Manual. I get tired of it sometimes especially in traffic and city driving. But then when I hook to a trailer or a heavy load is in the truck I appreciate the manual a lot...My dad's truck has a Alli in it and it's good but I pefer a manual.. My truck has only got the 6.0 but two of our shop trucks have DMAX's with the ZF 6spd and I really like them. Again don't buy a stick to say you have one because they can be a pain in the ass sometimes but if you figure on pulling I would always go with the manual.. IMO a manual is a just a superior tranny and That's my $.02

Hullie · December 11, 2002

I've got an '03 2500HD CC SB w/ the 8.1L and a 6-spd. It took about 7-8 weeks to come in, but was worth the wait. My wife wanted me to get the auto...but she also didn't think I needed the bigger engine (which I didn't ;) )

So far I've got 600+ miles on the truck. The first 2 tanks were completely empty w/o a tonneau cover and I got 10.6 MPG mostly highway. I expect to gain 1 mpg w/ the tonneau. I'm also planning on either bigger tires or installing the 3.73 gears (8.1/ZF could only get the 4.10s) to help w/ the highway mileage.

Unloaded 1st gear is completely useless. It gets you to about 6 mph. After a 1000 mile break-in I won't even use it anymore unless towing.

Ultimately I'm hoping to get to the 13+ mpg range on the highway...then I'll be totally happy.

BTW..my wife drives our truck. Looks kinda funny w/ a 110 pound blond behind the wheel..especially considering it's a stick, but she can handle it

Brett