676 and a quadbox

[Jocko]

Will a 676 flywheel housing bolt up to a quad box just curious

[Joe Ditchkus]

Jocko Theakerstwo will know for sure. If you are going to work the 676 and Quadbox its not such a good idea as the Quadbox is not heavy enough for the torque of the 676. If you do put an egg under throttle. Joe D.

[theakerstwo]

Will a 676 flywheel housing bolt up to a quad box just curious

Yes the quad or triplex or duplex will bolt up to the flywheel housing but then you have to have the proper bell housing on the trans so you can use the pull type clutch or use a push type clutch with the old 673 flywheel.

I need to change my mind on my statement above. I cant remember ever using a pull type clutch on a Quad.If I remember right you will have to use the push tupe clutch and flywheel and for a brake the Quad will have a brake on the end of the lower counter shaft.So I am saying you will have to use the flywheel from a older 673.

[Jocko]

ok what about a 350 is that the same thing. and will the flywheel from a 673 bolt right on to a 350 or a 676

[Bigdogtrucker]

What exact trans and rear gear ratio in this truck?Curious to your top speed...

[theakerstwo]

ok what about a 350 is that the same thing. and will the flywheel from a 673 bolt right on to a 350 or a 676

yes it will but that trans is limited on its torque.I think the bolt pattern will be same even on the E7.When you start mashing on your motor hard the bushing in the top gears on the main shaft would wera fast. And if your not carefull when you let the clutch out with a hitorque engine the clutch imput shaft will break at the oil pump bore in the shaft.Even tho that trans was used behind the twin turbo 864 the torque may be larger on some of the six cylinder engines of later years.If it is being used for a work truck I would want a twin counter shaft trans.

[Maddog13407]

yup, a quad will not hold up behind a 300 or 350. you will most likely grenade the back half of the box. a 237 is pushing it and will grenade a quad or triplex if you drive it like a cowboy. also some early duplex, triplexes and quads had 3/8 bolts in the bell instead of 7/16 like the later ones. may have to change the bell housing on the trans.

[skip]

There were a handful of mine spec trucks that came out here with 866s and quadboxes. They had to run synthetic oil in them as they would run too hot with mineral. But they were an exception to the rule. A 285 is about as much power and torque as you want to put in front of it if you are going to work it, and you would want to wind the torque screw in on the pump so it doesnt lug too much. A mate of mine had a 320 coolpower in his B61 and it handled it ok, but he looked after it, and he didnt work it day in day out.

[topo]

I brought home a Mack 675 a few years ago that had a Quidbox on it it was not original . The bell housing was a SAE # 2 and had 3/8 bolts I think SAE# 1 bell housings have 7/16 bolts both have 12 bolts . I returned the Quidbox to the salvage yard I needed the fly wheel for my 673 the input shaft on the Quidbox was 1 1/2 or 15/8 in diameter I don't remember . when looking at older Mack parts you never know that you will find bolted together .

[Kav]

Hi Jocko, Back in the 1970,s Mack in Australia would not allow a Quadbox on a 237 Maxidyne as they claimed that the Torque was too great for them. They said that the C motor which was 250 HP and lower torque than the Maxidyne was the biggest they would guarantee. They did a great job with the C Motors and would outlast the Motors in many cases, even when pulling road trains. The first Maxidynes which were fitted with the Maxitotque 6 speed Gearboxes had the same top overdrive ratios as the Quad, which was about .6 . These still had the Push Clutch fitted. The early V8's which were fitted with the Quads by Mack were not high torque motors, but you still had to be careful with them. - Kav