Transmission shudders and slips, especially in low. Reverse doesn't seem to be affected.

Torke converter needs to be replaced. Before you do that check the mounts.

2004 doesn't have a modulator valve . An if it did it would affect all gear operation , Shift hard , but would still go into gear. You have an internal transmission problem !
No Reverse, Slips in Reverse
Checks
Causes
Reverse Clutch
No apply or slipping
Piston and Seal Assembly (457)
Binding, cracked, or leaking
Inner Seal (456)
Plugged orifice
Clutch Plates (460-463)
Worn friction or broken splines
Snap Ring (459, 464)
Out of position
Housing (454)
Cracked, plugged feed holes, or broken tangs
Housing Retainer and Ball Assembly
Missing or out of position
Springs (458)
Binding
Reverse Clutch Fluid Routing
Fluid leak or restriction
Driven Sprocket Support (95)
?€¢
Leaking seal rings

?€¢
Porosity, damage, misalignment

Channel Plate and Gasket, and Valve Body, Gaskets, and Channel Plate
Porosity, fluid leak across the channels, misalignment, damage, or fluid restriction
Low and Reverse Band and Servo
No apply or slipping
Servo Piston (69)
Broken or binding
Servo Piston Seals (71, 72)
Leaking
Servo Pin (67) and Springs (66, 68)
Binding
Servo Cover (73)
Broken, loose, or leaking
Low and Reverse Band (111)
Broken, worn, or out of position
Anchor Pin (64)
Broken
Fluid Feed Tubes (83)
?€¢
Broken, bent, or plugged

?€¢
Missing or leaking seal rings

Transmission Case (1)
Porosity, fluid leak, or restriction
Shift Linkage
Disconnected or misaligned
Manual Valve (800) and Link (802)
Disconnected or misaligned
#1 Checkball
Missing, no low band fluid
Fluid Level
Low
Fluid Pressure
Low
Refer to High or Low Line Pressure .
suggest you take to an ASE certified transmission repair facility !

You need to get the transmission evaluated by a professional shop immediately. The symptoms you describe are a slipping transmission and a severe one at that. Slipping transmissions can be caused by low pressure inside the transmission which in turn can be caused by improperly installed filters (especially if this is a v8 Grand Cherokee). You could go to a quick oil change center and ask to have the transmission flushed _AND_ the filter changed. It might cure the problem... But that typically costs $120+ and a transmission shop will typically diagnose for less (half that).

Good luck.

It is an auto I take it and the problem will be a reverse band/clutch pack solenoid servo. It it is a manual then the clutch works the same way in forward and reverse so if it was slipping in reverse ,it would also be slipping in forward gears as well. Run the fault codes to check for TCM and servo/solenoid faults.

That seems obvious to me

You have a trans fluid leak
Didn't know it
The transaxle was slipping for sometime
Now it is ruined

Just because you changed the fluid doesn't mean if this is automatic transmission clutch plate chatter that will cure it. I have fixed this issue by using synthetic transmission fluid from REDLINE OIL. You can also try adding 3 ounces of STALUBE limited slip differential anti friction additive, it will not affect the transmission in any way but it does cure clutch plate chatter..

Without additional information it will be very hard to diagnose the problem.

1. Is it a manual or automatic transmission?
2. When you say pull do you mean that the engine is stalling out or that the car doesn't want to move forward - as in transmission slipping?
3. Have you noticed the transmission slipping before - especially in reverse?
4. Are the fluid correct?

Find a transmission servicer that is not afraid of tackling a Volvo problem. This is probably why the car was for sale in the first place. Good luck!

The transmission needs service. take it to a Transmission shop.

it doesent have to be slipping to go bad.youve lost reverse and it could be the solenoid on the side of the trasnmission but i dont think so since it would affect all the gears