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1987 Mack Twin Stick


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Hey guys,

I have a friend that bought a 1987 Mack twin stick roll-off dumpster truck and has asked that I do the driving for him. I'm am an industrial electrician turned teacher. I have my CDL and all of my experience is in an International 9 speed. I've seen several videos on you tube, but none actually explain what's happening as they go through the shift pattern. How many actual gears are there, are you splitting each as you go up, or do you go up so many and then split them? I know there's no substitution for time behind the wheel and that's coming up, but I also know I need to understand the process. Thanks in advance for your help.

Jeff

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Hey guys,

I have a friend that bought a 1987 Mack twin stick roll-off dumpster truck and has asked that I do the driving for him. I'm am an industrial electrician turned teacher. I have my CDL and all of my experience is in an International 9 speed. I've seen several videos on you tube, but none actually explain what's happening as they go through the shift pattern. How many actual gears are there, are you splitting each as you go up, or do you go up so many and then split them? I know there's no substitution for time behind the wheel and that's coming up, but I also know I need to understand the process. Thanks in advance for your help.

Jeff

I think you might be on the wrong trail here, I dont know that Mack ever used a spicer transmission and by 87 they were way past the tri-plex or quadraplex two stick transmissions. I would guess it has a 7spd or a 12spd the 7 speed would be one shifter shorter than the other and it would only shift the low-low I think they only did that with a seperate shifter for 1 year model then it went to air shift. The 12 spd has the same ide but the taller shifter has an airshift button on it, it would only use the smaller shifter on the left for low-low as well it would shift like a super ten on the taller shifter. I think that would be what you had in an 87 maybe not but that is probably it, it might be a twin stick 5 or 6 spd but I doubt it and if so it just shifts the range from low to high so you use one shifter 1-5or6 then shift back down and move the other forward then shift 1 thru 5or6 again. I'll check back but if you can tell me what the shifters have on them I can tell you how to shift it(ie: is one tallet than the other and one has airshift button on it) Ryan

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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I'm going back today, he needs an air line repaired and a tank strap needs welding. It was dark when I checked it out, but it fired up and ran great at 35 degrees. One shifter was straight and one had a knob on it. I'll find some of the ID stickers on it and get more info.

Jeff

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I'm going back today, he needs an air line repaired and a tank strap needs welding. It was dark when I checked it out, but it fired up and ran great at 35 degrees. One shifter was straight and one had a knob on it. I'll find some of the ID stickers on it and get more info.

Jeff

10-4 if it has an air shift on the tall one it probably has 4 positions high-low-neutral-rev that would be a TRTXL1070 or 1070B 12spd. Ryan

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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Hey guys,

I have a friend that bought a 1987 Mack twin stick roll-off dumpster truck and has asked that I do the driving for him. I'm am an industrial electrician turned teacher. I have my CDL and all of my experience is in an International 9 speed. I've seen several videos on you tube, but none actually explain what's happening as they go through the shift pattern. How many actual gears are there, are you splitting each as you go up, or do you go up so many and then split them? I know there's no substitution for time behind the wheel and that's coming up, but I also know I need to understand the process. Thanks in advance for your help.

Jeff

Actually, 1987 was the last year for the 2 stick 6 speed TRXL107 or TRXL1071.

The "main" stick on the left will be a standard 5 speed pattern, and the "compound" stick on the right will have :

Direct to the right and back, lo to the right and forward, and reverse to the left and forward.

You do not split shift this transmission. Basically, 1st on the main and lo on the compound is for severe starts off road or on a steep hill, other than that you leave the compound stick in direct and just shift the main like a regular 5 speed. If you're used to shifting a 9 speed, be aware that there is about 900 rpm between each gear on the main, so you'll have to let the RPM drop more for each upshift, or raise the RPM more for each downshift, compared to a 9 speed.

For reverse, you put the compound in reverse and use any one of the 5 gears on the main. 1st reverse is pretty much too slow to be of any use, 2nd and 3rd reverse are the usual gears I always used with that setup, 4th and 5th are too fast unless you're empty and have to back up a long distance quickly.

I've outlined the basics for you, there are a few tricks you'll learn for yourself after driving it awhile.

DO NOT "Jam" the compound into reverse while the truck is moving, those transmissions had a habit of taking a tooth off the reverse idlers if they were jammed into reverse too roughly.

.

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

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I think you might be on the wrong trail here, I dont know that Mack ever used a spicer transmission

Where did he say anything about a Spicer transmission?

and by 87 they were way past the tri-plex or quadraplex two stick transmissions. I would guess it has a 7spd or a 12spd the 7 speed would be one shifter shorter than the other and it would only shift the low-low I think they only did that with a seperate shifter for 1 year model then it went to air shift.

Actually the Mack 7 speed T2070 was a single stick transmission with R and 1 thru 5 on the stick and a hi/lo air shift button on the knob which was supposed to be used in 1st or 2nd for a total of 7 forward speeds and 2 reverse. The later T2070D had 1 thru 5 on the stick and rev, hi & lo on the air shift knob with a total of 7 forward gears and 5 reverse gears

it might be a twin stick 5 or 6 spd but I doubt it and if so it just shifts the range from low to high so you use one shifter 1-5or6 then shift back down and move the other forward then shift 1 thru 5or6 again.

Incorrect.

With the 2 stick 6 speed, lo on the compound is used with the main in 1st when working in severe conditions off road or starting off on a steep hill.

For on road use you leave the compound in direct and shift only the main. The ratios do not work out for split shifting, except that on the TRXL1071 you can 2 hand split it from 2nd lo to 1st direct, but that is not recommended by Mack, it's just a technique that was discovered by drivers that drove them daily.

I'll check back but if you can tell me what the shifters have on them I can tell you how to shift it(ie: is one tallet than the other and one has airshift button on it) Ryan

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

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HK, looks like you hit the nail on the head. I checked it out today and the shift pattern is the way you described. He's going by the HWY dept. Monday to take care of them and all parts for the air lines should be here also. I should have the tank strap repaired by then. After that I'll just haul when they call. When I get the hang of it, I'll help him study to get his CDL. I've tried to attach a pic, but it may be too dark.

Thanks for the replies,

Jeff

post-5280-12624840809933_thumb.jpg

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Where did he say anything about a Spicer transmission?

Actually the Mack 7 speed T2070 was a single stick transmission with R and 1 thru 5 on the stick and a hi/lo air shift button on the knob which was supposed to be used in 1st or 2nd for a total of 7 forward speeds and 2 reverse. The later T2070D had 1 thru 5 on the stick and rev, hi & lo on the air shift knob with a total of 7 forward gears and 5 reverse gears

Incorrect.

With the 2 stick 6 speed, lo on the compound is used with the main in 1st when working in severe conditions off road or starting off on a steep hill.

For on road use you leave the compound in direct and shift only the main. The ratios do not work out for split shifting, except that on the TRXL1071 you can 2 hand split it from 2nd lo to 1st direct, but that is not recommended by Mack, it's just a technique that was discovered by drivers that drove them daily.

The comment about spicers was narrowing the two stick transmissions, they are the only other maker to have a two stick trans and never in a Mack that I know of. I dont know everything about them all thats for sure just the ones I have been around but I do know I have been in a Mack u model with a two stick that had 5 on the main and hi-low on the second shifter and was told by the owner that it was a two stick 5 spd. I have never been in any others but that one with the range on a seperate stick and I have driven an R model w/a 300 and a 7spd that was a 7 spd air shift, the trtxl multi range trannys and the quadra-plex and tri-plex. I am only 31 I wasnt even born when some of the trucks I have driven were built. I will say you know your Mack tranny stuff I might have to call you on my next project truck. Ryan

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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84Superdog. Fuller also made 2 stick trans for many years they had 5X2, 4X3,5X3,5X4,6X4 all 2 stick trans. A friend of mine had a F-Model Mack with 335 Cummins and 4X4 Spicer trans. 2 stick in it. Joe d.

Good info I never knew Fuller made a 2 stick. Ryan

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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84Superdog. Fuller also made 2 stick trans for many years they had 5X2, 4X3,5X3,5X4,6X4 all 2 stick trans. A friend of mine had a F-Model Mack with 335 Cummins and 4X4 Spicer trans. 2 stick in it. Joe d.

You are correct on the 2 stick Fullers. I've also seen the 2 stick Spicer 4x4's and a lot of Spicer air shift 4x4's.

In 1978 I acquired a 1957 Autocar which had a 20C75 Fuller 5x4 trans in it behind a 190 Cummins. It was a "married" box similar to a Mack Quadruplex except that the main shifter was on the left and the compound was on the right.

Since I was used to shifting Mack quad boxes, I bent the levers around so that the compound lever curved to the left around the main lever, then bent the main lever to the right so that it was just like shifting a Mack quad box.

The history of that truck was that it originally had a Fuller 5 speed and a Fuller 3 speed auxiliary (which came along with the truck in the deal when I bought it), the 20C75 had originally been in a 59 White behind a 220 Cummins, and was installed in the A car shortly before I bought it.

I ran the Autocar as a tractor for a while pulling a trailer dump, then put a dump body on it and sold it less than a year later because it wasn't a Mack.

.

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

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HK, looks like you hit the nail on the head. I checked it out today and the shift pattern is the way you described. He's going by the HWY dept. Monday to take care of them and all parts for the air lines should be here also. I should have the tank strap repaired by then. After that I'll just haul when they call. When I get the hang of it, I'll help him study to get his CDL. I've tried to attach a pic, but it may be too dark.

Thanks for the replies,

Jeff

from Swishy's gallery-

http://www.bigmacktrucks.com/index.php?app=gallery&module=images&section=viewimage&img=5586

Producer of poorly photo-chopped pictures since 1999.

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Otherdog Wrote:

med_gallery_3420_646_454784.jpg

Yes Tom, that is the transmission I'm talking about, but it must be the Australian variation, as the shift diagram in that brochure shows the compound on the left, and the main on the right.

All the ones I've driven have the compound on the right and the main on the left.

.

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

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Yes Tom, that is the transmission I'm talking about, but it must be the Australian variation, as the shift diagram in that brochure shows the compound on the left, and the main on the right.

All the ones I've driven have the compound on the right and the main on the left.

.

yessir, I believe Swishy is Australian.

Producer of poorly photo-chopped pictures since 1999.

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HK

I remember driving a brand new 1986 Mack R Model Econdyne with a twin stick set up as a rolloff. I remember it having 5 speeds forward, and the other stick was a hi, lo and reverse, and I also remember upshifting in reverse. I was specing out 3 new rolloffs and the Mack sales guy brought me that twin stick demo model. I had seen the mack duplex etc. but never seen that trans before. I think it was considered a seven speed.

Also I work on a 1960 B85F Pumper that has a spicer trans- so even back in the day you could order a spicer if you wanted- it had full synchromesh in 1960, and the Mack 5 speed trans still needed to double clutch, so the fire company ordered a Spicer.

Firemack

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HK

I remember driving a brand new 1986 Mack R Model Econdyne with a twin stick set up as a rolloff. I remember it having 5 speeds forward, and the other stick was a hi, lo and reverse, and I also remember upshifting in reverse. I was specing out 3 new rolloffs and the Mack sales guy brought me that twin stick demo model. I had seen the mack duplex etc. but never seen that trans before. I think it was considered a seven speed.

That's a TRXL 107 or TRXL1071 6 speed, and it would be behind a Maxidyne engine.

Also I work on a 1960 B85F Pumper that has a spicer trans- so even back in the day you could order a spicer if you wanted- it had full synchromesh in 1960, and the Mack 5 speed trans still needed to double clutch, so the fire company ordered a Spicer.

Firemack

I am aware that Spicer transmissions would have been available in a Mack by special order, however I was stating in the previous post that the O.P. had not referred to a Spicer transmission.

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

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