Hello all,
My 94 4.0 4x4 manual (230,000 miles) is difficult to shift into first gear unless I hold the clutch down for a few seconds. I suspect the first gear synchro is toast, but I'm also an idiot and would like someone to check my diagnosis before I tear apart the transmission on my daily.

If I try to shift into first immediately after depressing the clutch, its blocked out. If I wait a second or two, it grinds as it goes in and then stays in gear just fine after that. If I wait four or more seconds, it slides right into gear, no problems what so ever. It feels like my first gear synchro needs more time to match speeds that it should.

If I engage second gear first, then drop into first gear, it always slides into gear nicely. This leads me to believe the 2nd gear part of the 1st/2nd synchro ring is matching speeds and allowing for a clean shift. I may be wrong and going into second gear may only be delaying the first gear shift long enough to make for a clean shift (see above statements about being an idiot).

I don't think its my slave cylinder because:
1: This problem is isolated to first gear. No other gears have any problems.
2: It fully engages at about 50% pedal depression. The vehicle free rolls when clutch depressed and in first gear, no tangible hanging up.
3. Through the inspection hole, I see no signs of leaks or damage.
4. I replaced the master and slave cylinders, the clutch and pressure plates, and the flywheel about 10,000 miles ago. All were original, no decrease in performance noted since then.

I'm going to get a rebuild kit and replace all the synchros, bearings, and seals while I'm in there. I noticed a good amount of wobble in the input shaft (approx. 5mm in all directions) while I was replacing the clutch. Hoping all new bearings will resolve that.

If ya'll see anything wrong in my diagnosis here let me know! Any feedback is appreciated.

 

Not a transmission issue, its a clutch issue or pilot bearing issue(but bearing usually makes a noise)

Transmission always spins at Rear Wheel RPMs, well drive shaft RPMs because there is no disconnect between rear wheels and transmission

So when you are stopped transmission output shaft RPMs are at 0 <<<

This means to put trans into 1st gear the Clutch disc/input shaft must also be at 0 RPMs
Clutch disc is sandwiched in between the flywheel and pressure plate which are BOTH spinning at idling engine RPMs, lets say 750 RPMs

When you press the clutch pedal down it pulls back the pressure, but it must pull it back far enough so 10" clutch disc is not rubbing on flywheel or pressure plate
If its rubbing even a little the 4" synchro can't slow the 10" disc down to 0 RPMs very well, if you force it you can overcome the rubbing but will get grinding
Yes, 2nd, 3rd, 4th or OD can make it easier, and once clutch disc is at 0 RPMs then it will easily go into 1st

Pilot bearing supports the end of the input shaft inside the crank shaft, this bearing allows the input shaft to slow down to 0 RPMs while crank shaft stays at 750 RPMs
So if its "tight" not spinning free it can cause the same symptom, clutch disc can't slow down to 0 RPMs

When you are moving its much easier to RPM Match engine and transmission
So it can be easier to shift into 1st while still rolling to a stop

I would try bleeding the clutch system first, very very common for Ranger to get air in the system which reduces the travel of the slave so clutch disc rubs and gets hard to slow down to 0 RPMs

On your transmission, the M5R1, Reverse is also synchro'ed, so try it when stopped, if it doesn't have the same issue then could be 1st synchro is worn down, synchos are a softer material so they don't grind but can wear down

 

There is a faint rattling noise that I neglected to add to the opening post. Tomorrow I'll see if I can't pull it out and bench bleed it again. Will report back after doing so.

Reverse gear engages smoothly at a stop, no delay at all.

 

With 200k mileage, I guarantee you have play in your input shaft bearing. I know mine did, and that wobble will definitely cause clutch disengagement issues. Given you said it had some wobble when you replaced the clutch, it hasn't gotten any better since.

I would follow the suggestions Ron posted first, check your clutch hydraulic system and try to bleed all the old fluid out. If this hasn't been done in a long time, it could use it.

P.S. Replace the pilot bearing while you're at it.

 

Well no change after bench bleeding the clutch.

I also checked how well the other gears engage at a stop and the only gear that needs any time to engage is first.

And yessir, if I go in there the pilot bearing’s getting swapped out too. I did also swap it with the clutch I mentioned but they cheap.