macattack

got either a trans problem or electrical issue. this is what happens. when i put my truck in drive the truck dies. i also have no reverse. no backup lites, alrm, camera etc.... when sitting idling there seems to be a slight misfire, when the misfire happens my reverse lites, camera etc... flash momentarily and the driveshaft looks like it wants to turn. i found 1 of the 5 circuit breakers were tripped. i reset it and tried again, but still nothing. i found 2 relays one for neutral the other for reverse, as soon as the part store opens i am gonna try replacing those relays and see what happens. i replaced the filters and cleaned the breather. oil looks great and there are no funny noises. i also found a silver box under the dash that looks like either a voltage reg or ign module?. would anybody have an idea of what is going on? thanks

gonna try replacing the reverse and neutral relays. i found 1 of the 5 circuit breakers tripped. i reset it and now gonna replace the relays as soon as the part store opens. hope that is the problem. any help?

does anybody know if a 96 mack e7 300 engine would have a cam timing sensor? engine does not have a computer? if so where would it be located? truck has a bosch fuel pump. thanks

thanks, truck was only out for about 10 minutes before she started acting up. this has a cable shift and that part seems to be fine. but this is what i found out today. truck is a 96(my avatar) it does not have a computer. i started the truck and let it idle for a few minutes. i just replaced the trans filters and topped up the fluid. truck is idling nice i then put it in drive and the truck dies instantly. i restart the truck and now about every 10 seconds or so a slight misfire happens. when there is this misfire my backup lites and camera flash on for a millisecond and my driveshaft wants to turn. does anybody know if the mack e7 300 engine would have a cam timing sensor or if my fuel inj pump is acting up. when it does misfire it only does for a very short time and then idles fine. 10sec later misfire then fine. i am thinking maybe a sensor or fuel inj pump and thats why it shuts off when i put it in drive. still no reverse though. dam i think this is gonna piss off santa.

did you get this fixed?

had this happen to me this morning in -30Celsisus. my 96 mr688s garbage truck had no reverse. picked my bin and selected reverse and nothing. put it in drive and the truck dies just like i pulled the red engine shutoff?. when i go to reverse all my backup lites.camera,alarm does not work. possible a short somewhere. but where do i look. do you think the nsbu switch? also when there is a misfire the driveshaft looks like it wants to turn????? the trans is an allison ht740rs automatic. would there be a relay or circuit breaker somewhere giving me trouble. thanks in advance.

i will try to get some pics later today.

did the front balance on my floats and fixed my problem. had beads added and was told it will take a few miles for the bag to seperate and spill the beads. but for now its definately helped my problem. thanks everybody.

sorry for misleading you about the spacers and longer studs. that post never came out sounding like it should. but actually it has the proper offsets installed. i was not sure what they were called so i just stated spacers. i did have the fronts off for the brake work and kingpins. mechanic said that its all fine. gonna throw some beads in my front floats and see what happens. sorry for the bad post.

thanks for all the responses. i am going to tackle this problem this week. i will post what i find.

thanks i will check that out also.

thanks rob. i will check into this.

how can i tell if its the proper offset?

is there anything he could of screwed up on when changing to the front floats?

what should i look at as far as the tires being changed to 425 65r 22.5. i know the previous owner stated he had to adj so the wheels the tires would not rub when turned. thanks for the info. the truck seems to steer great from one extreme to the other.

hi. thanks never thought of the pump. its a 96 mr 688s. my avatar is a pic of it.

thanks got to get them balanced. my fronts are brand new 425 65r 22.5 on alum rims. i know the prev owner had to install longer studs and spacers for the front rims. truck previously had some narrow front tires. thanks

my steering wheel is nice and steady. drove nearly 70 miles today, the rear balance didnt seem to help. feels like someone is pushing on the cab from left to right. one of these days i will find him. lol

hey. ok ive been battling this shimmy problem i have on my mr688s for close to 2 years. starting to drive me nutso. i dont operate it very much once twice per month. here is a brief description of my problem. at about 35-40 mph i get a shimmy/wobble in my truck. above and below that its fine. i replaced the following items. rear bushings insulator pads all. tie rod ends wheel bearings. king pins flex bar on front between spring hangers. replaced and retorqued hanger bolts. retorqued frame bolts. balanced my front rears. all u joints. few other misc items i cant recall now. still have the shimmy!!!. my question is should i have my fronts balanced 425 65r 22.5? i was told if my steering wheel does not shake its not in the front. but the mr688s cabover truck front tires are basically behind the seat. so is it possible the tire shop could be wrong. the fronts are on aluminum rims, i dont see any weights on the front rims at all. i had my front rears balanced with beads. tire shop told me it may take up to 100 miles before the bead bag breaks and balancing begins. is this correct? also i noticed that the front timbren type rubbers on the front springs are in contact with the trucks frame without weight. i dont think this is correct. maybe my problem is the previous owner installed oversized rubbers causing the wobble through out the truck. any ideas what else i should check? sorry for rambling on and on.

here in saskatchewan . 4 11r22.5 installed $1459.00 and 2 9r22.5 steers 700.00. my last set of 425 65r 22.5 cost me 1600.00 for a pair. damn.

well took it apart today and noticed only one washer on one side none on the other. the previous owner put the washer on the wrong side of the tube. repaired and reinstalled nice and snug now. thanks

thanks. gonna do a rebuild.

the washers are welded on the inside on both ends rite?

thanks guys. i think i am gonna reweld as is.

on my mack 688s mr i have a rod that goes between the front springs on the rear hangers. it is held by a nut on each end. what i noticed was it looks like its also welded on the inside. is this correct? looks to me the weld let go on each side. could i remove and just reweld the rod? you can see the weld spots on the rod. dont know if i should reweld it or replace. thanks