This truck has been giving me tranny problems for a while now. About a year ago, stopped in traffic in neutral, I attempted to shift into 1st but it wouldn’t go into gear, not reverse, not any gear. Eventually after a minute or so of trying it reluctantly went into 1st. About 6 months ago I started the truck after being parked and again it wouldn’t get into gear. Shut it off, tried to get it into gear, nothing. Checked the hydraulic fluid reservoir for the clutch and it looked a little low so added a bit and after that it shifted into gear (maybe coincidentally). Now about a month ago, it again wouldn’t shift into gear after being started. I checked the reservoir again, looked fine this time. Shut the car off, attempted to shift and this time shifted with ease
Something that I’ve noticed in the past year is that sometimes now when I shut the engine off it doesn’t run down smoothly; kind of slows then clunks to a stop. Didn’t used to do that
The problem might be that the clutch master cylinder is leaking internally and not developing enough hydraulic pressure to operate the slave cylinder. Usually when this happens, you can shift thru the gears without the engine running. But if you start the engine, step on the clutch pedal and try to shift into any gear it won’t go into gear because the slave cylinder can’t release the clutch. So this would be the same as trying to shift into gear without stepping on the clutch pedal.
It could be the above suggested or a synchronizer problem. Also, make sure the fluid in the transmission is also full and change it if this hasn’t been done in the past. Most suggest using synchromesh transmission fluid although some use standard auto trans fluid as it is thinner and allows for less resistance, producing slightly better MPG. I have a 1997 Ford that suggests ATF in the manual transmission. If this hasn’t been changed, I would do so.
You will have a fill plug and a drain plug in the transmission. Pull the top plug (fill) and see if you can touch the fluid with your finger. Dab some of this out with a white paper towel and make not of the color and odor. If it isn’t bright red on the paper towel and/or has a burned smell, replace the fluid. Also, if the fluid is low and you can’t reach the fluid, this could cause shifting issues.
Put an oil drain pan under the drain plug (lower) and remove it. Wipe all metal particles from any magnets and then replace drain plug. Refill with fresh fluid of the specified type and capacity. The simple way to tell full capacity is to fill until fluid starts coming out the fill hole. You should always be able to touch the fluid by putting your finger in the hole.
You might also change the differential at the same time if that hasn’t been done. This will probably call for GL-5 gear lube or similar.