macattack

how could i check these.

my rev switch is on the pass side and the nss is on the drivers side.

what is the best way to test them?

thanks for your info.

trying to do some diagnosing on my refuse truck allison ht740rs trans.  sometimes reverse sometimes no.  also at times it wants to kill the engine as soon as i put it into forward gear.   

with truck stopped and off if i put the shifter into reverse then into neutral and start the truck it will go into reverse ONCE.  wont go twice until i shut off the truck shift into reverse then neutral and restart the truck, goes into reverse.   also the acc/solenoid relay seems like its getting pretty warm  more hot than warm.

has anybody dropped the pan to replace the shift solenoids in the allison ht740 transmisson?

want to know if its a tough job and why you changed them.

thanks

guys

On 2/6/2017 at 8:40 AM, Mackpro said:

I believe there's a ground breaker under a black plastic cover mounted to the air cleaner housin bracket, this is all the ground to the cab. You might add cab to engine, cad to frame grounds. Worked on very few MR's as all the refuse companies and city owned MR/LE had their own shop's thank god! Lol. I looked for any diagrams that included the Allison and only had what I sent you the other day. We only have 1 old sheet on the VMAC 2 wiring . 

would this breaker box be approx 3x4 inch.  one wire on one side and 4 on the other. i found this under the center dash.  

maybe it is something else.

anyone know how to test a oil pressure switch 

and also can a person run a test on a  pneumatic/electric solenoid?  this solenoid has 2 same color wires coming off of it.

thanks gang .

i will check for the black plastic cover.

thanks again

got a new tcm for it.  damn kind of a bitch to get at on these units.  anyways got it out and the tcm looks pretty rough.  hope the new tcm  fixes it.

got to wait till monday to get the proper connectors.

anybody have wiring schematics for a 96 mr?

thanks

thanks.  which grounds?

hi guys.  this is on a 96 mr 688s refuse truck.

this is freaking me out.  got a ht740 allison 4 speed automatic.  has air mod valve and air operated throttle.

past week my trans temp gauge and speedometer gauge were jumping around in unison.  usually in neutral, but occasionally at road speeds.

anyways last week my gauges acted up again and the truck lost reverse and if i put it in drive the truck dies.

changed out the air mod valve, but still no reverse.

a couple times it went into reverse, the reverse lites came on my back up alarm worked and then when i tried again in wont go into reverse and no lites or alarm..

gonna replace the tcm.  i was told there is a solenoid pneumatic that maybe my problem  

any ideas.  thanks

testing my temp gauge and sender on my allison auto trans.

sender has a 2 wire pigtail.  

i believe one wire goes from sender to gauge , but does the other wire at the pigtail go to ground?

thanks

thanks for the reply.

yes its a 96 no electronics.

replacing a back up switch on my 740 allison automatic trans.

what i need to know is should the truck be running or not when i thread out the switch on the trans.

some say have the engine running so you wont loose any trans fluid.

with engine off fluid will spill out.

has anybody changed theirs and how much fluid will come out.

thanks

fixed it.

air modulator valve was bitched.   need to keep a extra in cab just in case.

i got a 96 mack mr688s.    

this morning sitting at idle my speedo and oil temp gauge needles were jumping back and forth.  all others were fine.

did it a couple more times but always at idle.

any ideas what i should look at.  

the speedo guage was replaced 8 months ago.  would it be a relay?

any help or things to check would be great.

thanks

thanks gang.

gonna fix her up today.

so i can use a barb fitting at the valve cover end also?

thanks

here is a pic of the nipple off the side of the housing. looks like just a push on hose.

i found a threaded hole on the side of the valve cover i am assuming thats where it goes.

so can i add a new nipple at the valve cover and just push both ends of the hose on or should the valve cover end have a secured hose?

thanks

had my oil change last week and noticed that on one side of the oil filter housing there is a small nipple on the side closest to the cab. looks like either the hose fell off or the mechanic pulled it off for the oil change and did not put i back.

any ideads where this goes to. i think its a vent.

its a 96 mack mech e7 350.

thanks

the speedo cluster was toast.

found a good deal on the bay and fixed it. replaced the whole unit.

thanks

thanks buddy.

did not think of the coolant lines.

my compressor has been leaking oil for a while and i think its time to replace. 96 mack mr688s.

how tough of a job is it to replace and is there anything a person should be aware of.

any tips are greatly appreciated.

thanks

thanks.

no its not digital. only 6 plug connector and a line of dip switches.

order a new speedo today. should have it in about a week.

my 96 mr688s speedo is working fine ,but the odometer and mileage meter are not working at all.

is there a seperate fuse for the odometer?

any idead which fuse?

the speedo cluster has a six wire connector. looks fine but will check more later.

thanks

thanks guys. gonna try slicing the hose and see if a socket helps.

thanks again

thanks guys.

i will try turning, (the steel around the hose) but not too sure if it will take a wrench. the steel around the hose seems pretty round.

thanks for the pic,but mine looks different.

here it is.

and she seems damn tight too..

should i try some heat??