Transmission fluid started leaking while pulling trailer. with trailer attached would not engage in drive only in 3rd gear. without trailer attached first gear engages. please help.

Based on the symptoms you described, it is possible that the issue is related to the valve body of the transmission. The valve body is responsible for controlling the flow of hydraulic fluid through the transmission and is made up of various valves and solenoids that regulate pressure and flow.
When the winter drive is engaged, the transmission may be bypassing the valve body and locking into third gear directly, which would explain why it starts in third gear when winter drive is engaged. However, the hard shift from 2nd to 3rd and the inability to shift into 3rd without winter drive suggest a problem with the valve body.
It's also possible that there could be a problem with the transmission control module (TCM) or the wiring and electrical connections between the TCM and the transmission. A diagnostic scan tool can help identify any error codes or other issues related to the TCM.
Given that you have already replaced the 2nd to 3rd shift solenoid without any improvement, it may be best to have the transmission inspected by a professional mechanic or transmission specialist who can perform a more thorough diagnosis and determine the exact cause of the problem. They may also recommend a rebuild or replacement of the transmission if the issue is more serious.

Hi. Before you do anything, check the transmission fluid level with engine running and in park. If the fluid is at the right level, there are 2 levels, a cold and a hot level. If the fluid is low then simply add fluid to correct level and check for leaks in hoses,transmission pan, external oil cooler if installed and axel seals. Normally fluid levels will not go down except if there is a leak somewhere. If the fluid smells burned, then you have most likely will need an overhaul as the tranmission has overheated due to high loads (pulling a trailer in hot temps, or simply because of age and the resultant excessive slippage of the friction plates.
However if the fluid level is good and fluid smells ok then gave the computer code read. Your problem could simply be a loose or corroded wire to or from the transmission causing erratic shift symtoms.
Good luck,
Gary

check fluid level in transmission . run the fault codes and look for a faulty TCM or torque converter clutch solenoid / servo

It is in "limp" mode which limits the transmission to only 3rd gear. The transmission fluid level needs to be checked and the "basic settings" need to be reset in the Transmission Control Module.

That doesn't sound good, sounds like a transmission problem. First try changing the transmission fluid. if that doesn't work find a reputable shop to take a look at it.

no problems before the mud deal but problems after the mud deal means that the problems started in the mud
check for mud in connections , wires disconnected , harness problems, vacuum hose to actuator broken or missing
run the fault codes to help point to a problem area
the transmission is sealed so there will be no need to change the oil or filter--just clean and check everything that is mud affected

suggest that you check your transmission fluid post haste please. you may only need to add transmission fluid to your car. also,if you have to add the fluid,where did your fluid leak? check for leaks under your car when parked. you may need transmission fluid and filter change,suggest that you do this with new filter and add lucas transmission treatment to the fluid change also. you'll need to purchase this yourself,unless you have a mechanic in the family that can do it for you.if not i suggest you find a mechanic you trust,then tell him,or,her to add this to your tranny fluid change. also suggest while the mechanics there at the transmission to check the modulator valve on the transmission,and the vacum line that operates it. just a hint. thanks for choosing fixya.com

You should not use overdrive unless you are steadily going highway speeds. I had one of those and my ex liked to use cruise control on windy coastal roads. This caused it to shift back and forth from 3rd to overdrive constantly. So I disconnected the cruise control so he couldn't use it. Lol. I'm not suggesting this for you. You should keep overdrive off for now and have your transmission serviced. New filter & oil & flush the cooler. Make sure you ONLY USE THE RECOMMENDED FLUIDS!!!!!!!!!! See if that helps. Do not use overdrive pulling a trailer and going up a hill and do not use it if you are on windy roads where you are slowing down alot of times. Try letting off the gas for a second when you do want to engage the overdrive. Remember to always check your automatic tranny fluid with the engine running and fully warmed up.

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Ok I see a manual transmission with a hydraulic clutch.
Get some fluid in that reservoir before you burn up the synchronizers.
Basically your clutch isnt disengaging because you are out of fluid. Next you need to find where the fluid is going. Likely the clutch slave cylinder is leaking and needs replaced. Pretty easy actually if you are handy with a wrench.

Try unplugging the electrical connection on the transmission to lock it in 3rd. It might get you moving. Although the transmission is going to need rebuilt or replaced.