transmission fluid change G56

[KBrody]

Of course my warrenties up, I changed the transmission fluid about 3weeks ago. 6 qrts of amsoil, ATF, no problem. Started it up to move her and it sqeaked in 2nd and in reverse, went away after a day or so. Headed over the mountains to Moses Lake with my 30 ft toy hauler. Seemed to have no problems back and fourth. Tues headed to the base and as I down shifted to 2nd if shaked and shimmed. Drove it home and I have a gnawing sound at 55 and the shakes when I slow down. Even when I push the clutch it and coming to a stop it still shakes. The only thing I did is pulled the drain plug, reinstalled it, pulled the fill plug, 6 qrts. Is there some rocket science dealer thing that I missed?

 

[Andersonville]

I would put the Mopar ATF4 back in it. It is synthetic.

 

[Bob V]

Might be a bad u-joint. Feel if any are hot after a long drive

 

[JBonpua]

I would put the Mopar ATF4 back in it. It is synthetic.

Amsoil is also synthetic. Did you somehow accidentally dropped a small tool in the fill hole? I did my G56 and tcase at the same time 4 months ago and no issues. It might be a U joint like Bob V said.

 

[CDonaldson]

I am running the Amsoil ATF with NO problems, on my 2nd fluid change-did the first one at 15K, 2nd one at 30K. Actually, all my fluids in the transmission, xfer case and diffs are Amsoil products.



Might be a u-joint?? Your symptoms sound like it, you need to check temps, check for play, or both. Usually you will feel a slight vibration on acceleration first, gets worse under towing load or over time.



I have ane of those electronic temp testers, my transmission, xfer case and diffs ran hotter with the Mopar fluids, running much cooler with the Amsoil fluids. Amsoil is synthetic also.



CD

 

[DPKetchum]

Does not sound fluid related

 

[GCroyle]

KBrody,



Can you tell us your mileage please?



The G56 uses a Dual Mass Flywheel, at higher mileages SOME trucks have reported a vibration. If you put the truck in neutral, engine running and accelerate the engine, if you get a vibration if could be the DMF has lost its balance. Might want to try various rates of acceleration and deceleration, engaged and disengaged but do it in neutral, that takes out the drive shaft etc.



If you confirm a stationary vibration test and DO NOT have any engine related causes (others can chime in and explain better) then the secondary side of the DMF is most likely loose on the primary side, orbiting around the crankshaft centerline and you get 50 Lbs worth of DMF and clutch that are out of balance. The secondary is piloted by a bushing, bushing can wash out on one side allowing secondary to orbit.



Doesn't get better, not fluid related if it is the DMF.

 

[JCasper]

I bet it's a U-Joint

 

[Motorhead]

I bet it's a U-Joint

I THIRD that opinion.
Jack the rear end off of the ground and check the driveline by turning the driveshaft back and forth while holding the drive shaft on EACH side of each U-joint. Look also for rust powder around any of the U-joint bearing cups.

 

[2broke2smoke]

i am no fan of scamsoil ...



but many use it on here with good results ...



sounds like a u-joint ...



c'mon you just gotta take advice from a guy named Motorhead