Motor Mounts / trans mounts

[JGrefenstette]

a few months ago i replaced the transmision mounts under my getrag. before i replaced them there was serious clunking when taking off from a stop and sever clunking when in reverse with the clutch not fully engaged. we i first replaced them it seemed to solve most of the problem. but now its almost worse than it was before. are my motor mounts bad??? when cruising in any gear between 1500-2000rpms if i abrubtly let off the throttle it will thump, and it does the same if i abrubtly hit the pedal while coasting in gear. this is extreamly agravating and feels as if somthing is going to break. if im on a hill and have to use reverse... . lord have mercy, feels like the transmission/motor are going to fall out of the truck. drives me absolutly nuts! ive ignored this problem long enough and i want to solve it, any advise would be apreciated.

how difficult are motor mounts to replace? cost of new mounts? will 2nd gen. 24v motor mounts work on my truck? my buddy has a set that he doesnt want.



thanks

 

[TWorline]

Have you checked the carrier bearing assembly for sloop. While you under there see if you can turn your driveshaft at all, you may be getting excessive lash in your rear end.

 

[JGrefenstette]

yea i replaced the carrier bearing and all three rear u-joints a few months ago. the drive shaft turns slightly but i dont think any more than normal. ive lifted the hood and watch the top of the motor as i let out the clutch in 1st-2nd or revese and i can see it torque up, and if i grab the throttle linkage on the IP and rev the motor up it moves the whole motor. so i think thats what it is. but not 100% sure

 

[PToombs]

If you hold the brake, put it in 1st and reverse, and let out the clutch, if it has a broken mount, you'll see it! I've had 318 gassers jump up 3-4 inches. Scare the shirt out of ya!

 

[JGrefenstette]

how much will it move if its a broken mount? if i replaced the trans mounts, doesnt this only make sence that its the motor mounts? or could the trans mount bolts be too loose?

 

[Niki]

Sometimes motor mounts get so bad the motor looks like it'll jump out of the truck. I guarantee almost every firstgen could use new motor mounts, just because of age. If you have any oil leaks it turns them into mush also. Motor mounts are something like $20 ea. You probably need to lift the motor by the lifting eyes on top though. I wouldn't trust jacking a Cummins up by the oilpan, just too heavy. Whatever you do be careful if you plan on doing it yourself, make sure everything will stand up to the weight.

 

[dpuckett]

There is a guy who did a good write up on the "other" Dodge diesel site in the 1stGen forum. PUt a bottle jack on a block of wood or concrete block, and jack it up by the lip of the oil pan, essentially lifting it by the edge of the block. The mounts come out fairly easy.



24v mounts will NOT work on a 1stGen.



I'd check the rear end for excesive play. If you can turn the driveshaft more than about 30-45 deg before it grabs, you probably need new spider gears- easy change, though I dont know how cheap. That should take up most of your slack, since you changed the u-joints and center support bearing.



Like Niki said, motor mounts are cheap, and not hard to do.



Daniel

 

[JGrefenstette]

ok thanks guys. daniel, i assume you are talking about jacking it up from the front of the pan on the front side of the cross member (oposite end of the drain plug)?



does it matter if i use the hoist loop in the front of the head? becuase my oil pan leaks, and is dented in the front, i would like to avoid puting any abnormal pressure that might incourage it to leak more. im going out right now to double check the driveshaft play. thanks again yall.

 

[Niki]

There is a guy who did a good write up on the "other" Dodge diesel site in the 1stGen forum. PUt a bottle jack on a block of wood or concrete block, and jack it up by the lip of the oil pan, essentially lifting it by the edge of the block. The mounts come out fairly easy.



24v mounts will NOT work on a 1stGen.





Like Niki said, motor mounts are cheap, and not hard to do.



Daniel

I would definitely not jack anything up with a concrete block between the motor and a jack, if that would crumble your hands are going to be right there to get crushed. That lip is probably only 3/4" wide, pretty dangerous if you ask me.

 

[Mopar_Tim]

i used the lip on the passenger side to jack the engine up to put in the mount when i swapped it in the trailduster frame ..... it was safer then you would think it did not move at all

 

[PToombs]

I did one on a 4bt in a backhoe last week. Just put a 2x4 on a floor jack on the side lip of the pan. Worked good! The 2x4 bites in and can't slip. A bottle jack would be better, no wheels.



If you wanna be safer, put a jackstand or block from the floor to the pan side for safety.

 

[therabbittree]

the engine hoist is easier in my opinion. . that show i've done any oil pan work. etc.

 

[JGrefenstette]

i noticed probly 20-30* rotation in the rear driveshaft. i havnt done the brake and let out the clutch in 1st or reverse yet. thats next, probly tomaro after i take it to class.

 

[DValentine]

I found the shaft that holds half of the spider gears had worn at 110K, when I bought the truck. It was not hard to replace. Take the Diff cover off and have a look. You can look into the carrier, as it has holes in it. Work the tire back and forth with the truck in gear. You will see the slop.

 

[JGrefenstette]

so you think thats my problem... not motor mounts???

 

[DValentine]

Did you do the first to reverse test with the brake on? Did the gear shift move back and forth? I only recommend looking at/in the diff, because you said your drive line moved a bunch. That indicates some excessive slack some where in the drive train.

 

[JGrefenstette]

i was talkin with one of my buddies, and he asked if my rear end could be adjusted? he said the ford rear ends have shims in them, but he thought the dodges could be adjusted?

 

[JGrefenstette]

i did do the brake on, i didnt notice the stick all that much. im pretty certain it did move though. when ever i shut off the truck if jumps all over the place as the motor jerks to a halt.

 

[Philip]

If you can turn the driveshaft more than about 30-45 deg

HHHMMMM Daniel you better look in the manual. The amounts you have shown is wwwwwaaaaaayyyyyy to much. Most of the time if an axle is that loose its trashed. Jeremy's first W350 had bad bearings and teeth gone off the pinion and it didn't have that much slop.



2 to 3 degrees is more like it for driveshaft movement. 5 degrees max.

 

[DValentine]

The stick will move, as the engine is rubber mounted. But you are looking for the stick to lay way over, when you do the test. This will show a broken mount, as the engine torque will try to overcome the brakes.
You can change the depth of the pinion gear against the ring gear. You also can move the ring gear from side to side with shims. On my truck the shaft holding two of the spider gears, located in the carrier, was worn. I took it apart and replaced the spider gears and shaft.