99 Saturn SL1 automatic transmission jerking each time gear changes. I have had two other transmissions and a rebuilt computer put in, but it still does the same thing. Wiring harness has been checked out also. Does anyone have an idea what the problem may be?

That can be a mount, but you would of said it jerks at all time from park to drive and when your driving. and also reverse.Going from park to drive is there a pause and do you hear a buzz noise then a gear change. If you did that would be the solenoid. So here it is from park to drive and the RPM is in range this is known also as a harsh up shift, it is mechanical in nature the clutch pack is taking more pressure than it need to achieve a gear change. In other word your transmission is mechanically worn

96-99 SL1, SC1, SW1. Avoid the 2 models, they are DOHC and have different gear ratios

2001 Saturn SL1. Transmission (automatic) shifts hard when putting it in gear and every gear there after. The only codes I get is PO442 and PO410. Any help would be greatly appreciated.

Time to find a much lower mileage used tranny and have it put in. Replace the clutch components with new stuff while you are at it.Note that the transmissions 91-99 will most likely swap but you must know whether you have an SL1 or SL2 and the donor car must be the same..

That I'm not sure about yet. Do me a favor and pull the trany dipstick and put your nose really close to the fluid on the stick and see if it smells burnt.and is the fluid red or brown.

You may have a failing valve body which tends to hang up on metallic debris. Several electronic actuators are present in the valve body and their elctro-magnetism draws this metallic debris then hangs valves.replace control valve body

The issue is most likely due to a worn transmission valvebody. The problem will get worse over time. It is caused by not changing the transmission fluid often enough.

Only solution is to have the valvebody rebuilt or replace it with a new one. Its not a difficult job, but the removal and installation steps have to be follow precisely.

your transmission has possibly been rebuilt with stronger springs put in. No worries. have been running mine for along while without any problems. Better this than slipping, but it is a bit annoying.

I had a 1991 Dodge Caravan that did the same thing. I had a transmission rebuilt because of the problem you describe. I was told it was a seal inside the transmission that was leaking fluid from an internal chamber when the engine was at an idle (like it is when you are at a stop sign). A redesigned seal fixed my problem. I would bet if you gave it a little gas with one foot and kept your foot on the brake it wouldn't act like it had dropped out of gear. If you have the money for a transmission rebuild that might be something to consider but if you are tight on money, a bottle of lucas transmission additive might help your problem. That seemed to help me so I could get some money together for a transmission rebuild. I realize that most mechanics will say that your transmission doesn't need an additive of any kind, I also realize that sometimes in real life you have to do what your pocketbook/ wallet can afford.

Good luck.

its because your saturn motor is manual and your car is automatic i have the same problem thats whaat they told me