Warpman89 Posted November 16, 2007 Share Posted November 16, 2007 I just started driving an 88 R688ST with a 10 speed, the one with a 5 speed box with direct, high, neutral, and reverse for each gear. Often it grinds when I pull it to the next gear. For example, when shifting from 2 high to 3 direct, I shift to direct and pull the lever to neutral and I starts grinding in Neutral. It does the same thing from 4th to 5th. Is this common, or am I doing something wrong. Don't get me wrong, I've driven several eaton fullers with gear splitters, so I understand the concept. I'd like to know if there are any tricks to the trade. Give me a break and don't laugh, I'm a newbie! Quote Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/ Share on other sites More sharing options...
theakerstwo Posted November 17, 2007 Share Posted November 17, 2007 I just started driving an 88 R688ST with a 10 speed, the one with a 5 speed box with direct, high, neutral, and reverse for each gear. Often it grinds when I pull it to the next gear. For example, when shifting from 2 high to 3 direct, I shift to direct and pull the lever to neutral and I starts grinding in Neutral. It does the same thing from 4th to 5th. Is this common, or am I doing something wrong. Don't get me wrong, I've driven several eaton fullers with gear splitters, so I understand the concept. I'd like to know if there are any tricks to the trade. Give me a break and don't laugh, I'm a newbie!I think you have a 6 speed trans not a 10 speed and you dont split each mainj gear. Try to start out in low and 1st gear and go up to direct and 1st gear and up to direct and 2nd gear and direct and 3rd gear and up to direct and 4th gear and direct 5th gear. glen Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/#findComment-15098 Share on other sites More sharing options...
MACKS Posted November 17, 2007 Share Posted November 17, 2007 I have the same tranny in my 83 RD I like to split the gears with the stick in netural, always a little grind in the higher gears, make sure you have the right gear oil 80 or 85 weight is best and change the air filter on the tranny. Quote Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/#findComment-15103 Share on other sites More sharing options...
Warpman89 Posted November 17, 2007 Author Share Posted November 17, 2007 I think you have a 6 speed trans not a 10 speed and you dont split each mainj gear. Try to start out in low and 1st gear and go up to direct and 1st gear and up to direct and 2nd gear and direct and 3rd gear and up to direct and 4th gear and direct 5th gear. glenTake my word for it, its a 10 speed. I've seen this exact same tranny in several of the same era macks and they are all 10 speeds. The winshield visor gives the shift sequence: 1D 1H 2D 2H 3D 3H 4D 4H 5D 5H, in that order. Besides, if you just leave it in high or direct and go through the gears, the gears are spaced too far apart for a heavy load. Quote Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/#findComment-15107 Share on other sites More sharing options...
Warpman89 Posted November 17, 2007 Author Share Posted November 17, 2007 I have the same tranny in my 83 RD I like to split the gears with the stick in netural, always a little grind in the higher gears, make sure you have the right gear oil 80 or 85 weight is best and change the air filter on the tranny.I know what you mean. I've noticed that if you listen between shifts for the gears to slow down, and then shift, you have less grinding. But for the upper gears, there's just no help it seems. Quote Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/#findComment-15108 Share on other sites More sharing options...
skip Posted November 18, 2007 Share Posted November 18, 2007 I just started driving an 88 R688ST with a 10 speed, the one with a 5 speed box with direct, high, neutral, and reverse for each gear. Often it grinds when I pull it to the next gear. For example, when shifting from 2 high to 3 direct, I shift to direct and pull the lever to neutral and I starts grinding in Neutral. It does the same thing from 4th to 5th. Is this common, or am I doing something wrong. Don't get me wrong, I've driven several eaton fullers with gear splitters, so I understand the concept. I'd like to know if there are any tricks to the trade. Give me a break and don't laugh, I'm a newbie!I know where you're coming from mate. My brother had an Ultra Liner with a 12spd and the gear linkage was fairly heavy and slow which seemed perfect for shifting. There always seemed to be a bit of a tingle going form 4D to 5L, it just had to be a bit slower. Now hes got a superliner and it seems very hard to get a smooth shift in 4th and 5th. And when you grate a gear you know all about it! Im not much of a driver but he goes alright and still has the same trouble Quote Link to comment https://www.bigmacktrucks.com/topic/3087-excessive-grinding/#findComment-15134 Share on other sites More sharing options...
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