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12 speed shifting question


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Hi guys,

 

New here. I just bought an 87 Mack R688st. First, I wanted to say thanks because I was able to fix a bunch of things on the truck just off of the information I found on this forum, so it's been invaluable.

 

Anyway, I have a 12 speed e6 350. (I'm a new driver)

Having a bit of an issue with the truck stalling, wondering if I should be doing something different.

 

I turn the truck on. Build up air. Push in the brakes. Push in the clutch shift the truck to 1st direct and then the truck stalls.

 

 

My question is:

 

 

Should I be revving the truck as I'm letting off the clutch to get into 1st gear?

 

Do I need to rev up a certain rpm?

 

I.e. shift into 1st at 1200 rpm?

 

Thanks guys

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Release the parking brakes. Yellow air valve on the dash. If you are doing this already ("push in the brakes") then the rear brake shoes are most likely seized to the brake drums from sitting.

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1st direct is High range. isnt your shift knob round with an air switch that goes sideways? 4 positions. lo-direct, nuetral and reverse.

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2 minutes ago, mowerman said:

Sounds like you’ve got electrical issues.. bob

How would electrical issues relate to this?    terry:MackLogo:

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stuck brakes for sure can do this.. Was a brake chamber replaced right before this and the lines were switched?   I'm trying not to throw out a dozen things on this thread. I bet its a simple fix..

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I had a problem with 2001 Fruehauf I sprayed wd-40 in glad hand brakes were hanging up and changed glad hand to a quick release one on blue side good now......it would hold a little air back ?

 

Ed

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Well he didn’t mention anything about letting letting the clutch  out and the engine governor is connected to the transmission (electric) Possibly shorting out and killing the engine

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Posted (edited)

My 2 cents worth sez (Tax FREE)

the engine brake is on or short n out n try n 2 stall the cold motor

it twould make the engine sound like crap

Butt

There again

Wot Would eye kno

LOL

cya

Edited by Swishy
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I think we're missing some more details. We don't have acknowledgement that hes releasing the parking brake.  When did the truck roll last? Has it been sitting for a long time? What work did you have to do on it?

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