Mack Posted September 15, 2005 Share Posted September 15, 2005 I need Info about 5x4 gears box,I just buy a 79-R609 and have the 5x4 gearbox and 673 turbo engine tamden 12-00-R-20.The top speed is very low only 43 Mph at 2000+ RPM.Any one knows the gears of this gearbox or were can I found more info Online look like I have a 4.10 or more.I will like to more info on the 673 engine too. Quote Link to comment https://www.bigmacktrucks.com/topic/364-i-need-info-about-5x4-gears-box/ Share on other sites More sharing options...
Freightrain Posted September 15, 2005 Share Posted September 15, 2005 oldmacksrus.com has all the info on motors/trannys/etc.Look on the drivers side of tranny and you'll find the number telling you what it is....TRQ-XXXX (the last digits telling if single/double O/D ) With that road speed I would bet you have 5+ something gears or worse!One question? What is a '79 doing with a 673/quad box in it?? Seems pretty new for that combo. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/364-i-need-info-about-5x4-gears-box/#findComment-1605 Share on other sites More sharing options...
Superdog Posted September 15, 2005 Share Posted September 15, 2005 Must be a misprint,R609's weren't made that late.Must have been repowered too,it should have a 711. Quote Link to comment https://www.bigmacktrucks.com/topic/364-i-need-info-about-5x4-gears-box/#findComment-1611 Share on other sites More sharing options...
Lmackattack Posted September 15, 2005 Share Posted September 15, 2005 I dont think quads were options after the late 60s. a BCR could easly have one and if you have a 673 with a quad. it might be an early R model from the late 60s early 70s? the late 70s had numbers like 686,685 etc... Check your vin number on the frame rail near the pass front wheel to see what the truck came with...if its for shure a 79, it very unlikely that the quad came from the factory. My B61 has a quad and 5.73 rears..thats good for about 62 mphtrent Quote Link to comment https://www.bigmacktrucks.com/topic/364-i-need-info-about-5x4-gears-box/#findComment-1612 Share on other sites More sharing options...
Mack Posted September 16, 2005 Author Share Posted September 16, 2005 The engine and the quad box came from factory even in the cab have the metal stikers for the gears.This truck is non USA made may is this.thanks for the link. Quote Link to comment https://www.bigmacktrucks.com/topic/364-i-need-info-about-5x4-gears-box/#findComment-1625 Share on other sites More sharing options...
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