Need help

[cfd511]

I have a 2001 Mack RD688 dump truck which was county owned at one point . I don’t know how it felt when it was new but it seems really difficulty to shift all the time. It’s always grinding . The tranny is the 18 speed maxi torque connected to the Mack 400 . Is this normal or should I get it

looked at.

[Mack Technician]

You have much prior experience with driving a Mack transmission? Or your first?

[cfd511]

this is my first mack

[david wild]

Get used to it, they're junk.

[AZB755V8]

11 hours ago, david wild said:

Get used to it, they're junk.

Really, Junk???  Those 18 speeds are  all I got in my trucks with no issues. Have to replace the clutch brake once or twice, a $20 part, but almost indestructible. The trucks went though a few drivers and owners though.

Come on face it a real driver can shift a Mack 18 speed with no issues. An old Quad-box would be out of the question and was junk too? All you Road Ranger pansies have syncro's to get the next gear. Guess the next time its an automatic for you Guy's. If it keeps grinding have it looked at but first don't try and shift it fast. Get some seat time, maybe a lot of time, let the rpm's wind down about 350-400 rpm's before going for the next gear. You just can not fast shift a real truck transmission.

A Mack triple coutershaft trans does have a learning curve. Yes it would be nice if it fell into gear but then anyone could drive with one. They shift just fine, do need the right touch to drive and a little brains.

Edited February 22, 2019 by AZB755V8

[Dirtymilkman]

On 2/18/2019 at 6:19 PM, cfd511 said:

I have a 2001 Mack RD688 dump truck which was county owned at one point . I don’t know how it felt when it was new but it seems really difficulty to shift all the time. It’s always grinding . The tranny is the 18 speed maxi torque connected to the Mack 400 . Is this normal or should I get it

looked at.

That setup should be a honey to drive. I ran those for 20 years now and the only issue I've ever had was the snap ring break on the Hi-Lo shaft. Simple to shift. Let her drop 400 rpms if you're not splitting and it'll fall into the next gear. 

[Mack Technician]

9 hours ago, cfd511 said:

this is my first mack

I’d say “normal” and don’t get it looked at. They have a real learning curve, especially if your coming right out of the Eaton Fuller camp and into a Mack. Mack stole some design points from Eaton, when they built the Mack T300 series, to make a more positive shift. Most obvious was the slider clutch redesign. 

If your over the road your better off with an Eaton for low operating cost, higher efficiency, replacement/parts/reman availability, ease to drive, etc. 

If your in the dirt, Mack will make money for you(Aside from relearning how to shift). Mack is shadowed by an aftermarket line of parts that are OEM quality, PAI Industries. They under-cut Mackvo dealership parts somewhere to the tune of 30% which makes running a Mack more practical.

Good luck & Safe travels!!!

[fjh]

2 hours ago, Mack Technician said:

I’d say “normal” and don’t get it looked at. They have a real learning curve, especially if your coming right out of the Eaton Fuller camp and into a Mack. Mack stole some design points from Eaton, when they built the Mack T300 series, to make a more positive shift. Most obvious was the slider clutch redesign. 

If your over the road your better off with an Eaton for low operating cost, higher efficiency, replacement/parts/reman availability, ease to drive, etc. 

If your in the dirt, Mack will make money for you(Aside from relearning how to shift). Mack is shadowed by an aftermarket line of parts that are OEM quality, PAI Industries. They under-cut Mackvo dealership parts somewhere to the tune of 30% which makes running a Mack more practical.

Good luck & Safe travels!!!

Sorry bro !! I would like to rephrase that comment for ya Tech they charge what the part is truly worth ! Their not tryng to sell you a new truck by making it not worth while to fix !! They are  just selling parts to fix A worth while truck!! 

 

Just sayin!

[david wild]

      Maybe for you guys with little lowbeds and dumptrucks can get away with the Mack 18, but they have not held up well with big loads,  since most of us are older and been driving since last year we should be able to shift a Mack, I started in  B model with a tri plex, the failure rate is higher with the Mack trans than the fuller 18, the 4 reverse gears cannot be beat but the overhaul every year is a bummer,  I thought the 3 countershafts would hold up better but appears that 2 is enough,  and if the Mack is so great how come in the coal feilds they went to the 8LL ??  and yes we use automatics and they heat up and stop, we see things from a different perspective, what works in one vocation does not work well in others, and I know as a swift driver moving half million pounds transformers that we may not know much but were not the ones watching we are the ones doing. 

[Dirtymilkman]

Anytime you gotta rebuild a tranny every year might mean that driver may have issues. Ours are running 90,000 plus with liquid loads. We do change grease every 350,000 miles. 

[david wild]

90k is less than our empty weight

[AZB755V8]

1 hour ago, david wild said:

90k is less than our empty weight

What is your empty/ loaded weight? What trans are you using that holds up to your loaded weight and what engine, rears? If you are talking about that monster Fuller 18 speed it will handle more torque and shift better than the Mack trans by a good margin. Is there an auxiliary trans involved as well?

Excuse all the questions but curios to your application. "Normal" 80-90K day run loads is what I am used to and talking about.

[Hayseed]

On 2/22/2019 at 12:48 PM, cfd511 said:

this is my first mack

Those mack Boxes are nowhere as smooth/supple  to change as a Roadranger.. Definitely an acquired skill...

 

17 hours ago, Mack Technician said:

I’d say “normal” and don’t get it looked at. They have a real learning curve, especially if your coming right out of the Eaton Fuller camp and into a Mack

^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^

On 2/22/2019 at 2:24 PM, AZB755V8 said:

All you Road Ranger pansies have syncro's to get the next gear

There's only One Syncro in an 18 speed Roadranger. & that's in the range change...BISTBC

[1965]

Mack has a heavier 13 & 18 spd box too. 

T318L21 & T318LR21. Only the LR models can be used in low or high range reverse & shouldn't change range while moving. The reverse deal is the same in all 13 & 18 trans.

[david wild]

Before one makes comments about drivers ability they should consider what some drivers do, we have 3 transformers that are now permitted and getting ready to move, Transformers weigh 491,000lbs total gross weight 724,000lbs 18' tall and 20' wide on 30 axles, making comments about their ability is like a golf cart driver commenting on a F1 driver ?  last weeks easy load was from New Holland PA. to West Palm Beach FL. port, 88,000lbs 14'11" high 12' wide  no big deal, 61'8" in the well, try that with 4" of ground clearence and not get highsided (stuck)  before that we took overhead crane beams to Matamoros MX, not the border but into MX 165' long, the police down there did as good as any cop here and cost less.  Next month we go with same beams to Juarez MX, infact we go to MX enough that we are working with our customs broker to open a trucking operation down there so we can continue to move our own freight, this is along with 100 other loads that got moved,  95% oversize

So here's the deal I'll send one of our CH's with a 2180 to the dealer of your choice, they can rebuild/overhaul the trans(this is a running trans) if it will go 10,000 miles before it starts making grinding sounds i'll live with it if not someone else eats the bill, I'll even keep it off real big loads.

With 5 19 axle trailers too many 13s and 9s  40+ lines Goldhofer,  hybred dual lane Goldhofer and  trail king dual lane I think their is not a driver shift problem as much a bad product. many drivers, one trans same problem, all the drivers can't be bad but the same problem comes up with same trans. 

[AZB755V8]

1 hour ago, david wild said:

Before one makes comments about drivers ability they should consider what some drivers do, we have 3 transformers that are now permitted and getting ready to move, Transformers weigh 491,000lbs total gross weight 724,000lbs 18' tall and 20' wide on 30 axles, making comments about their ability is like a golf cart driver commenting on a F1 driver ?  

There is no need for funning back and forth like I started. What you are doing is way out of the "normal" trucking, with permits, escorts, DPS involvement , etc. just to move 2 feet on a road and take 2 lanes. As implied like a Alaskan bush pilot comparing experiences to a 747 transcontinental  air-captain.  There is just no comparison.

Back to the trans, what is your trans of choice? What is the spec's on your trucks? Who many truck are hooked to a load at one time? Any shock load with that much weight is going to damage some driveline components even with a good driver, it happens I am sure. 

[david wild]

Western star, cummins, 18 speed fuller AT1202 aux trans 4.56 rear ratio with DT hubs 3 to1 reduction. so for those that don't know, DT Hub is a 3 to 1 reduction hub that will either go 1 to 1 or 3 to1 reduction, so if you had a 90 mph truck in 1 to 1 you have a 30 mph truck with hubs in 3 to1 cut that by half with AT 1202 and the trans in low you will measure distance in how many seconds it takes to travel a foot. load 4 axle truck to 80k with weight box lift pusher drive other 2 axle in the ground and still spin wheels, or just for fun you can watch sidewall of tire wrinke when you pull into it hard.  Kenworth  would not build that spec truck only western Star. for just general  trucking CH Macks have been great, tried the Granite but the AI engine just won't do. Have petes, they do fine, the transformers will get pulled and pushed with 2 Kenworth C500, cummins power, Allison trans and DT hubs. Western Star and the Mack are my personal preference.  I will defend any of the drivers that run the big stuff, these  guys are hand picked and receive way more training than other drivers,  like me many of them have trucked overseas because of the lack of talent in some sh thole countries we get to visit.

[cfd511]

thanks for the replys . Its def a learning curve. i started letting rpms drops 300-400 rpm and slowed my shifting down and not let the revs go so high and boom shifts a lot better. thanks again .

[Mack Technician]

Salute, Keep a rainy day fund for an occasional synchronizer swap-out and happy sailing!