Toyota Surf jerks while shifting on idle

[qaiserbhatti0189]

i have changed my engine and transmission yesterday in my toyota surf 1996 from 1kz to 3RZ petrol with origional engine gear and wiring. i pulled out from an origional petrol surf. every thing went fine except the jerk in shifting from N to D or R to D.
i changed the drive shaft and differential too from that petrol surf to my diesel surf.
i drove that spare petrol surf myself and there was no jerk while shifting but now when the mechenics remove and inatalled every thing to this new vehicle this problem showed up.
can anyone help me to indicate what possibly could have gone wrong. suggest a check list plz.

[UAHMAD]

Hopefully, the mechanic was reliable and ensured following during the swap:

• Engine was placed on the correct position of mounts and the swap was done properly.

• New OEM mounts/foundations were used instead of the ones taken out from the donor car.

• Transmission oil was also changed.

• Drive shaft U - joints were inspected for play and looseness, and were greased during fitting.

[dani_kk]

Looks like you're running low on transmission fluid or fluid lines are bent while swapping. Kindly tell us how much fluid was used?
And which city you're from?

[qaiserbhatti0189]

thnx thes all measure were taken except oil change. mechenics told me that was not necessary

[qaiserbhatti0189]

i didn't change fluid.

[dani_kk]

So you're saying you didn't remove radiator or oil cooler pipes and directly migrated everything in to ur surf from other surf?