1G Jerking at low rpm's!

[eclipse_16g]

I finally got my car on the road after putting my engine into this new shell. After driving around I noticed a hard jerking and loud bang while driving in 1st or 2nd gear at very low rpm's. It happens when I put slight pressure on the gas pedal, and when kept steady with slight pressure at low rpm's.
Also only when I'm decelerating where the driveshaft meets the rear dif is rubbing on my exhaust.
There were no bolts in the top of the rear dif mount, so I put them in, and tight, also checked every bolt holding the differential in place, still them same thing. Changed out the rear suspension with Agx adjustables, and Eibach pro kit springs, still the same thing.
I also replaced the driveshaft with one with good carrier barrings on it, stiull the same thing.
Any input would help, thank you.

 

[mitsu-luver]

How low are the rpms when this happens? Im pretty sure everyones car jumps like that if its too low...

 

[undefined0000]

jerking, heh.

 

[Tyeler18]

On your differential mount, were there bushings in it? Since there were no bolts I'm going to assume there was no bushing in it?

 

[97 DSM Gs-T]

How do your motor mounts look? My car jerks really bad at low rpms and im pretty sure its because my mounts are shot. Waiting on money to get some new ones.

 

[eclipse_16g]

I have poly inserts in my tranny and d/s mount, the others are good. The lower bolt slot on the block for the rear mount has broken off, but still has the upper spot bolted on.
Yeah my other car used to jump, but this isn't just a jump, it's a bang, I feel like I'm gonna get whip lash when it happens.
I'm not sure if the mount has the bushing but I will check, where should I look for them?
Why would my differential be scraping my exhaust only on deceleration? I can see that it's not hitting when the car is not driving. It's like the dif is falling down and rubbing it. It's a full Apexi n1.

 

[Tyeler18]

I have poly inserts in my tranny and d/s mount, the others are good. The lower bolt slot on the block for the rear mount has broken off, but still has the upper spot bolted on.
Yeah my other car used to jump, but this isn't just a jump, it's a bang, I feel like I'm gonna get whip lash when it happens.
I'm not sure if the mount has the bushing but I will check, where should I look for them?
Why would my differential be scraping my exhaust only on deceleration? I can see that it's not hitting when the car is not driving. It's like the dif is falling down and rubbing it. It's a full Apexi n1.

Because under decel your differential is attempting to rotate down, on acceleration it's attempting to rotate upwards. If you don't have those bushings in, it's free to rotate as it pleases as the bushings are part of what centers the housing.

 

[1998_gst]

check your intake after the maf, I've seen air leaks when the engine torques at lower RPMs, check the clamps or tears if you still have stock intake

 

[meangreengst]

did you ever solve this issue?