Fld 120 possible motor mounts / clutch problem

Sure sounds like the engine is moving around to me. Pull the trans, put a clutch in it along with a rear main seal if its wet. The mounts will be in your face with the trans out of chassis and will take minutes instead of hours. If the rears are shot, get the front mounts too, they are likely just as old.

Just what I would do.

 

I would stop at the nearest safe place! Is there a gap between the bell housing and the flywheel housing? Is the flywheel housing cracked and or loose on the engine? #### the load do not have a major blowout.
I was driving a vehicle once that the clutch started slipping. I was baby dolling it. Noticed on a hill when I clutched it to down shift it stopped slipping but something seemed odd. As it got worse I found if I just clutched it and stayed in the same gear it would stop slipping. Dropped off at the next exit and pulled in the only gas station. It was dark and raining. No service just gas. The guy opened a door and let me noise up in the shop. Found the lower bolts missing and or stripped out. Took some bolts out of the front bumper braces that were the next size up. Ground the threads like a tap on their bench grinder. Beat on the heads with a hammer while working back and forth. Got it sucked back together, threw him some cash and got home.
That is often a rear mount and or bad bolts. You may get by with just one for a while. Goody has good advise for long running.

 

The mounts aren’t too hard to replace. The engine is twisting giving you the slack in pedal. Best remove oil pan, using a block of wood and bottle jack to change rears, fronts have a nice bracket for jacking. Also check cab bushings near firewall. Once all the bushings and motor mounts are done. The heights/ distances will be correct, then make sure linkage ends are good, May need to adjust linkage and/ or clutch if it’s been adjusted in the past to compensate for worn parts. Safety first, I almost lost the end of my finger, cutting corners by not removing oil pan. Unless you can lift engine from top. Either way block it good. Watch those fingers, lol

 

You bring valid points to not Jack on the oil pan for obvious reasons. Lifting from the top is an option but overhead or gantry is not in everyone's shop bay. Rough sawn oak timber blocks and quality bottle jack's that dont bleed down in the correct locations can get the job done without oil pan removal. 10 ton Porta power can work as a slim jack on the pan rail as well.

 

I jacked it one side at a time on the side of trans. After getting done, I found a plate I missed sitting inside frame rail. I thought it odd to only have one “ shim” while doing the other side. So I redid the first side, and got careless as it was around midnight , I took a chance and jack slipped, smashed my finger like a grape. One of the dumbest things I’ve ever done,having known of 3 people who lost their lives to a jack. I doctored it myself for 4 mos, A trip to hospital would have been 10 times what I saved in labor, I lived but that left hand middle finger bandaged up got a lot of inquiries, I’m not too proud to admit my mistakes if it can help someone else avoid it.

 

Can’t be too careful, my next door neighbor, smart Guy, Great Mechanic, missing half his foot from an engine on a faulty chain fall. If Something like that can happen to him, after years of Diesel Wrenching, Anything can happen.

 

You don't have to jack anything. Drop the trailer open the hood lock the brakes and find another trucker. Put the truck in 2nd or 3rd and with the other trucker watching let out the clutch,slowly and with minimum fuel. The guy watching should be able to tell you where the motor and trans are moving, easy- peasy.

 

Ok .......Brake torqueing will find out if the mounts are shot. I wanna see you replace em before the engine comes back down. Lol

If you can do that I'll hire you right now and pay you twice steering wheel jockey wages.