Cruising - deceleration drivetrain bucking

[eclipsegst1990]

Having interesting problems with my manual transmission. I have a 1991 Galant VR4 and the vehicle is bucking as if I'm in too high a gear when foot is off the gas and just cruising under the vehicle's own momentum.

For instance, let's say I'm in 5th and cruising at a low rpm and too low a speed for that gear...the bucking you get while doing that is the same bucking I get in "ALL" gears while cruising under closed throttle in the "proper" speed and rpm range for the necessary gear.

Also similar similar description would be like if you leave the car in 3rd and coming to a traffic light and forget to put the car in neutral before stopping - similar bucking. It kinda feels like the rear wants to run over the front. However, when I press the gas, this symptom disappears.

The car shouldn't buck in 2nd going 15 to 25mph with foot off of the gas pedal. Press clutch in and we're fine or touch the gas pedal and symptom is gone. Seems only in deceleration or off throttle cruising.

Lastly, what can happen to my AWD drivetrain if my vehicle is towed by a j-hook tow truck where it is lifted from the front. Could it be lifted from the rear if steering wheel is secured from moving?

 

[eclipsegst1990]

Well, since nobody has had any ideas or suggestions, I think I figured this out for myself. I'm thinking that the vehicle has a bad viscous coupling now which can make the car jump forward at times when the torque isn't transferred properly between the front and rear. Seems like one's trying to catch up to the other feeling and the vehicle jumps a little. So, with that being said, I'm assuming it is a PITA to replace the viscous coupling or is there an easy way instead of dropping the trans/diff etc? Most replacements I've seen are when the trans is out of the car.

Also, the damage to the viscous coupling makes sense too because an idiot friend of mine towed the car on a j-hook. I told him not to, but the tow driver didn't think there would be a problem. FLAT BED YOUR CARS PEOPLE!

 

[Mr PopUps]

Theres a big red/orange sticker on the drivers side door jamb that tells you this... its been known for 22+ years

Replacing the VC isnt that bad, it can be done on the car too. You just remove the outer/end casing and its right there with the 5th gear assy. Youll need a new spring clip as they are a one time use item only.

 

[jtmcinder]

Your symptoms do not match problems with a center VC.

 

[Mr PopUps]

Agreed, but at least he now knows its not that tough of a job to do. Last time i did one, i got the 'on the car tear down and reassemble' down to 8 hours... .