No. If the ATF level is correct there is no magic potion that will fix it.
Some take atf some gear oil, others specific manual trans fliud.
The transmission does not take gear oil. The auto uses ATF+4 and the manual uses manual trans fluid.
6.8 pints of 75W-90 Manual Trans Gear Lube.
Check the fluid. If full, take it to the trans shop.
Take it to a service shop and have the trans checked for codes.
On a 1990 Ford Ranger ; The 5 speed manual Mitsubishi transmissions ( trans code " D' ) take 4.8 pints of 80-90 W gear lube The 5 speed manual Mazda transmission ( trans code " M' ) takes 5.6 pints of MERCON automatic transmission fluid
BUY A BOOK OR CALL THE DEALER AND ASK THEM you need to take the speedomiter cable out of the transmission remove one 10mm bolt i belive and there will be a gear on it and it will say add or low on it its simple
Hey Jason==Probably something inside the trans. TAke it to a a good trans shop. Good luck Joe Maintenance and Help Section May offer some assistance, but it sounds like you might need to take it to a dealer or transmission shop.
The Transmission filter is on the Inside of the trans. The only way you can change it is to take trans apart.
The biggest problems of why a jeep wont go into third gear is either that the shifting fork for third gear is worn or bent or the sycronizer or gear itself is worn out and needs to be replaced. Once you take the top of the transmission off where the shifter is located you can see the whole transmission gears and inspect the shifting forks. A general rule of thumb is to make sure the transmission is in second gear before taking the top off. This will make it easy to take off and rerattach the top of the transmission cover and align the shifting forks.
You have to go to the dealer to get the transmission fluid! go to a local autozone or someplace and ask i believe its dextron III not sure
Too much transmission fluid in the trans or pressure build up. Check the fluid level as outlined in your owners manual. If it is not overfull, take the vehicle to a transmission professional.