Jump to content

Mack 7 Speed


Recommended Posts

Hey truckers! Just registered on this site! Glad to be here among all you Mack lovers. Getting ready to purchase my first Mack this week. It's a 2000 RD690S tandem axle dump, with a 16 ft steel body. It has the E7 300 mated to a Maxitourque 7 speed. I am impressed with this ride but the 7 speed has caused some concern for me. She seems to be a bit stubborn even when double clutching. Is she an extended range tranny in so that it should be around 1200 rpm for downshifting and against the peg for upshifting. I am used to an Eaton 8LL. In my trial run with the seven speed I ground the gears alot when I first took off but as my run went on I was getting a little smoother. If you have any tips at all I would truly appreciate your feedback.

Link to comment
Share on other sites

Hey truckers! Just registered on this site! Glad to be here among all you Mack lovers. Getting ready to purchase my first Mack this week. It's a 2000 RD690S tandem axle dump, with a 16 ft steel body. It has the E7 300 mated to a Maxitourque 7 speed. I am impressed with this ride but the 7 speed has caused some concern for me. She seems to be a bit stubborn even when double clutching. Is she an extended range tranny in so that it should be around 1200 rpm for downshifting and against the peg for upshifting. I am used to an Eaton 8LL. In my trial run with the seven speed I ground the gears alot when I first took off but as my run went on I was getting a little smoother. If you have any tips at all I would truly appreciate your feedback.

Yes just dont get in a hurry and let the rpm come down and dont put your foot on the clutch. you will get good as time goes by. Glenn Akers

glenn akers

Link to comment
Share on other sites

this make me laught. We own a 1987 R model tractor 300Hp with a 7 speeds. This Mack is simply undestructible. not the way you should shift a truck but sometimes when me and my brother get crazy and think that we are at the races this tranny can be the best one. from second to third it's a powershift. keep the pedal to the metal, the other boots right under the clutch pedal and swing that stick... yess it works! pretty sure the wheel come off the ground sometimes. all the big bird and Cummins are impress how this little Mack pull.

Link to comment
Share on other sites

the 7 speed is a fast transmission (.60 overdrive? will have to check my books.)

you likely will have slow rears so it wont be 2 fast. I think it was David that said that the fast drive train speed helps reduce stress and shock in the mud? The 7 speeds I have driven were all pretty good and the 2 low gears did help startup on a hill, at least a little better than the 2 stick 6 speeds

Link to comment
Share on other sites

Yes..it is an .60 overdrive. My 88 with 65,000 lb rears and a 7.58 ratio will top out at 62 mph. 1200 is about right on the money for down shifting.....however tight you can get it to turn is good for upshifting :D I have ran one hauling coal (35-45 tons) in the southern West Virginia Mts sinc eit was new in 88 with 1 bearing kit. The things are unbreakable. Mackattack was right in the fact that the 2 low gears are a dream for pulling out in bad places and hills. It is definitely an extended range tranny. You cant get in a hurry with them but they usually get a lot better over time on ease of shifting. High gear seems to be loud in everyone of them also.

My only kick was the darned splitter...you had to make dang sure you were in neutral before you flipped ranges are it grinded like it was gonna explode but after 17.5 years it still hasnt :D

Link to comment
Share on other sites

Good choice on the Mack! Mack's are made for dirt work...I've been driving Mack dump trucks for 21 years and there's nothing better for on-off road work!

The shift troubles you are experiencing is common for people who move from Fuller transmissions to Mack transmissions. With a Fuller transmission, the timing between gears is the same for each gear, but with a Mack transmission, the timing between gears gets a little longer as you shift up through each gear. For example, 2nd to 3rd is a longer wait than 1st to 2nd, etc. The old joke with the shift from 4th to 5th took so much time that you could take it out of 4th, go get a cup of coffee, and come back and shift into 5th! :D

If you are in a real bind, you can shift with the Jake on, which will bring the RPM's down quicker and you can upshift quicker. I don't recommend this as a daily practice, as it's too much "shock" on the driveline.

Practice the timing and you'll have no trouble!

Link to comment
Share on other sites

  • 2 weeks later...

Hey truckers! Just registered on this site! Glad to be here among all you Mack lovers. Getting ready to purchase my first Mack this week. It's a 2000 RD690S tandem axle dump, with a 16 ft steel body. It has the E7 300 mated to a Maxitourque 7 speed. I am impressed with this ride but the 7 speed has caused some concern for me. She seems to be a bit stubborn even when double clutching. Is she an extended range tranny in so that it should be around 1200 rpm for downshifting and against the peg for upshifting. I am used to an Eaton 8LL. In my trial run with the seven speed I ground the gears alot when I first took off but as my run went on I was getting a little smoother. If you have any tips at all I would truly appreciate your feedback.

Keep at it, you will figure it out-these things are tough-just remember these things are designed to pull & last-just use low range in bad situations -dont buck jump her-these are not the fastest trucks in the world but you sure can make money with em.If you mess up dont cram start over-Kevin

Link to comment
Share on other sites

  • 2 weeks later...

this make me laught. We own a 1987 R model tractor 300Hp with a 7 speeds. This Mack is simply undestructible. not the way you should shift a truck but sometimes when me and my brother get crazy and think that we are at the races this tranny can be the best one. from second to third it's a powershift. keep the pedal to the metal, the other boots right under the clutch pedal and swing that stick... yess it works! pretty sure the wheel come off the ground sometimes. all the big bird and Cummins are impress how this little Mack pull.

Ouch!!!!!!!!!!!!!

"If You Can't Shift It Smoothly, You Shouldn't Be Driving It"

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...