Mack quadruplex question

[ranchhopper]

Question is can this be stuffed into my superliner without massive modifications spoke to the owner he says its new old stock I have spoke to him on the phone seems honest enough.I like these old transmissions are they strong enough for a 300 plus engine to be used with will they even bolt up to the existing bell housing on my 300 I will have to find a yoke to fit on the output shaft what do you guys think.

[terry]

If it is a hobby truck maybe, A working truck probably not, you can mate them up alright. you have to remember these were behind engines with not alot of torque. terry

[ekennedy21]

I would say it would be a no go. There are other transmissions that would work way better with the 300plus. That transmission would always be one footful of throttle away from destruction. I would use a mack 7 or 12 speed if I were you.

[terry]

I would say it would be a no go. There are other transmissions that would work way better with the 300plus. That transmission would always be one footful of throttle away from destruction. I would use a mack 7 or 12 speed if I were you

A 7 speed and a 12 speed take a whole different rear end ratios. I believe the 7 speed is around a 5.50 ratio and the 12 speed a 4.17 or 4.42 terry

[jackb61sx]

I would not due it, what's in it now for a trans. Mine has an 8 LL with 5.02 rears and 425 hp in it.

[ranchhopper]

That's what I was thinking the trans couldn't take the torque of the modern engines I appreciate the opinions it has a 10 speed roadranger now just looking over all the options now the cab will be off the truck in the spring no better time to swap the trans if I so desired.

[theakerstwo]

And this trans don't have a bell housing on it so you would have to find one.Plus that trans there may be for a push type clutch.I can think of a lot of problems you will run into.

[mrsmackpaul]

dunno the old quad box is pretty tough not a patch on the maxi torque though

they had the quad box behind the 325 and 375 V8's out here on road train work so they gotta be pretty tough 325 was a Maxidyne and 375 Thermodyne pretty sure thats the way it went my 20 cents I reckon it would be ok

Paul

[GOOG]

Ranch, have you ever driven a quad?

[ranchhopper]

Yes I have used a quad, duplexes, triplexes, I like the old school tech of the day.

[Bigdogtrucker]

This truck had a 300/quadbox. Ran daily for years in CT and she hauled HEAVY .

[Wobblin-Goblin]

This truck had a 300/quadbox. Ran daily for years in CT and she hauled HEAVY .

I am in lust.

[theakerstwo]

Another thing wrong with using a old trans is ever day you go to work you have to wonder if its going to shell out and then you set for weeks trying to find some used parts.

[Maddog13407]

I'm betting that truck had a 300 maxi dyne and not a 300+ thermodyne. If you baby it you might make a quad last, I wouldn't wanna count on my paycheck tho running a quad behind a 300

[Bigdogtrucker]

I'm betting that truck had a 300 maxi dyne and not a 300+ thermodyne. If you baby it you might make a quad last, I wouldn't wanna count on my paycheck tho running a quad behind a 300

I do know one thing, the truck I posted was not babied and didn't run light. There were several others in my area that had Maxi/quad combos that did the same for many years.

[theakerstwo]

I can remember back when these trans was still in production and seen many come in with the trans making a lot of noise and it would be the bushing in the mainshaft gears worn out.Low end torque is harder than hi end HP on thoses bushing.That is what caused the twin and triple counter shaft trans to be invented.Those bushing were replaceable but it took a tool to roll them in after been pressed in.

[Underdog]

It all depends on driver knowledge and skills. No need to apply full torque in low ranges. Let the proper gear do the work. Same reason we see single countershaft transmissions again today. Electronic controls prevent shock loads and over torque. These skills used to be the old school drivers responsibility.

Sent from my XT1254 using Tapatalk

[ranchhopper]

Im old and that being said I drive a truck like its my own (in this case it is mine) always figured if you take care of it you wont lose a day or two of work while its being fixed. I shake my head at the jack asses calling themselves truck drivers the way they beat a truck we have quite a few of them where I work.

[m16ty]

My brother has a quadruplex behind a 318 Detroit. The truck was a heavy hauler back in the day. The old quadraplex is still holding up.

[ranchhopper]

Another consideration is the fact the truck has 3.70 geared drives Im not much of a mathematician so it may not be compatable there either.

[terry]

I can remember back when these trans was still in production and seen many come in with the trans making a lot of noise and it would be the bushing in the mainshaft gears worn out.Low end torque is harder than hi end HP on thoses bushing.That is what caused the twin and triple counter shaft trans to be invented.Those bushing were replaceable but it took a tool to roll them in after been pressed in.

I believe they called that broaching the bushing. terry

[Vladislav]

Another consideration is the fact the truck has 3.70 geared drives Im not much of a mathematician so it may not be compatable there either.

The most of math seems me "as faster as better" if we talk about a bobby truck. You have a planty of low gears in any heavy truck transmission.

[jackson.hancock.@gmail.com]

Do you think you could beef one up maybe by putting bigger or stronger bushings and stuff in a quad 

[theakerstwo]

3 hours ago, jackson.hancock.@gmail.com said:

Do you think you could beef one up maybe by putting bigger or stronger bushings and stuff in a quad 

How would you go about doing that and were would you get them?

[Freightrain]

I think the biggest drawback is the single countershaft.  They won't take the torque no matter what you try to upgrade inside.