Transmission shuddering when accelerating around corners

Question edited for clarity, Lubegard and Shudder, not 'shutter'.
Question moved to vehicle category.

https://www.canadiantire.ca/en/pdp/lubegard-transmission-instant-shudder-fixx-56-ml-0380673p.html

Yes you can.

• Transmission Instant Shudder Fixx is a concentrated friction modifier formulated for eliminating torque converter shudder problems - instantly
• Works with any automatic transmission fluid except Ford Type F and CVT applications

Shudder is usually a transmission concern with the torque converter. 40 MPH indicates a range in which the tcm engages torque converter lock up, and most shudder concerns happen at this time. Need a scan tool to be exact. Obviously could be another concern. Without driving I would not know. If it is a shudder, in my experience a complete transmission service with filter and friction modifier will usually remedy the concern in the short term... however... complete rebuild is not usually far off in the future. I have seen other internal transmission issues following this about 20 to 30,000 miles after fixing the shudder

Sounds like an engine misfire.Does the check engine light come on or flash. If so, it may be a spark plug or ignition coil issue. The transmission can also cause a shudder problem. These transmissions are usually rather dependable though.

what year a older one or a new model ?please describe shudder a bit better is it shaking the steering wheel or just make the whole car shudder? is it clonking going around corners ?

possible due to mileage on vehicle, you may need to service your transmission. if fluid is real dark in color, do not service transmission.lube guard is a supplier that makes and treatment for this problem, which is called shutter fix. torque converter clutch is causing this problem when transmission goes into lock up. let me know if you need additional information

as long as the trans does not slip while shifting gears, you may need a torque convertor. you may be able to minimize the shudder by changing the fluid and filter, but that may open a can of worms causing the trans to go bad.

This car has both options of auto transmission plus manual gear **** so the only reason it can shudder when the clutch is not fully released and thus takes some time, that's when it shudders, but on accelerating this will not happen cos the centripetal clutch has enough torque such that the clutch is pressed hard to the cam & therefore no shuddering. On cruising speed the probability of clutch slipping making the car shudder. Thus changing the clutch assembly ought eliminate this problem....sodeep

I'd shudder too at 260,000 miles. . By shudder, do you mean vibration?. U-joints usually show up at around 45 mph. So try to narrow it down.

I had a similar problem on my 93 Accord after I accidentally threw the car in reverse at 50 mph, obviously wrecking the transmission. When I got it rebuilt I was told the transmission pump was to blame (clogged with "shrapnel"). I, and your car manual, recommend taking the car in to get the tranny looked at. Especially considering you just had the fluid changed which is what would normally cause the problems you are describing.

try by replacing the spark plugs and the plug wires and add some injector cleaner to the fuel tank