Mack Transmission question

[mandt428]

I have a X107 6 speed transmission, 2 sticks, reverse high and low 1 stick, 5 speeds 2nd stick. The transmission is in a 1978 R Model with a 237 h.p. motor, with 4.5 diffs, top speed around 95 klms, around 58 mph.

I have just had the rear diff re-raced.

The transmission also sounds like it needs re-racing. With this 2 stick box, I am able to split each gear giving me 10 forward gears and 5 reverses.

The question is, is there an overdrive transmission similar to the X107 transmission?

Maybe an X1070B transmission?

Mick Downunder

[kscarbel2]

Mack produced a 7-speed overdrive Maxitorque transmission designated TRDLG-1070. You split 4th and 5th gears.

[mrsmackpaul]

you are not meant to split the gears with the deep reduction stick and it should not be able to be shifted unless its 1st there is a mechanical inter lock inside the top of the box to prevent this

And the deep reduction is such a big step I dont think it would be practical to try and split the gears anyway

hope that answers your question some one else who knows more about the transmission numbers than me might be able to put me right

Paul

could you change the diff ratios ??

[MACKTRUCKS4]

you are not meant to split the gears with the deep reduction stick and it should not be able to be shifted unless its 1st there is a mechanical inter lock inside the top of the box to prevent this

And the deep reduction is such a big step I dont think it would be practical to try and split the gears anyway

hope that answers your question some one else who knows more about the transmission numbers than me might be able to put me right

Paul

could you change the diff ratios ??

The trans that locks in low range is the 12 speed. The 6 speed should NOT be used to split every gear except first. The bearing in the trans that is used for low range is NOT designed to spin at higher speeds and the bearing ends up failing. I am not sure if there is a 6 speed that is an overdrive..

[b61mack]

I think there is a air shift 6 speed that is an overdrive, don't know what number. the one I drove was a 88 R model with a 300, 555 rears, would run around 65 to 70 mph, the old 76 285 seems to have more power than the 88 with 300 4 valve.

[terry]

I think there is a air shift 6 speed that is an overdrive, don't know what number. the one I drove was a 88 R model with a 300, 555 rears, would run around 65 to 70 mph, the old 76 285 seems to have more power than the 88 with 300 4 valve.

That probably was a 2060 series trans. Very wide gearing, was not a popular trans. Terry

[mandt428]

HI what is your thoughts on fitting a 12 speed 1070B to my 237hp r model truck is used to cart timber

from coast to high country about 90 miles up hill all the way. mick

[terry]

The 12 spd can be hooked up to a 237, but it sure would be nice to have at least a 285 horse engine. Terry

[RAYMAC]

yer I would go 4 the 12 speed but be carefull early ones are only low and direct on air switch later ones direct and overdrive a gear 4 every situation I found better behind the 237 the coolpowers seem to fall on there backside under 1400 rpm a note on the 6 speed the one I drove was overdrive box 2 stick passenger side stick was direct neutral and overdrive stick closest to driver standard h pattern reverse 1 2 3 4 5 wind it up before shifting into overdrive was a big gap cheers ray

[ws721]

The trans that locks in low range is the 12 speed. The 6 speed should NOT be used to split every gear except first. The bearing in the trans that is used for low range is NOT designed to spin at higher speeds and the bearing ends up failing. I am not sure if there is a 6 speed that is an overdrive..

I have a TRXL1070 6 speed that has a .62 overdrive. 22.5 tires with a 5.73 ratio gives it 72 mph at 2100 rpm