Grind when engaging 1st gear

I've started noticing an issue with my 96 2.7L 5spd 4x4. In certain instances, when I push the clutch in and move the shifter into 1st, I get a grind as the shifter engages 1st.

For example, if Im sitting at a light in N, when the light turns green, I push the clutch in, move the shifter into 1st, and hear a quick and loud "grrrrind". Once the shifter is in 1st, everything works fine: ease the clutch out and continue on my way.

This noise also occurs on downshifts into 1st as well.

The funny thing is this doesnt happen on every shift to 1st. For example, again, if Im sitting at a light just playing around with the shifter with the clutch depressed moving it from gear to gear. The first time I engage 1st, it may grind, but every time afterward its quiet and with no issue.

Obviously, something in the driveline is wearing. My question is is this clutch related or tranny related? Anyone have any idea what the issue may be?

My truck has 185K+ miles - about 3-4K miles ago, I changed the tranny, differential, and T/C fluid to Mobil 1

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90. I had no issues until now so i dont suspect the fluid.

 

In my experience with manuals, that would usually happen when the trow bearing needed replacing. Another suspect would be the clutch master cylinder (if it has one).

 

It does have a clutch master cylinder, but I was kind of thinking T.O. bearing as well. Just wasnt sure what the symptoms were.

 

I would go for the cheapest first (trow out bearing), that is if you are doing the work yourself. Then My second option woul be the master cylinder or plunger; both can be checked without having to drop the tranny if I'm not mistaken.

 

could be 1st gear syncro going too, you aren't doing it any favors by grinding it...will it go into other gears while stopped and engine running, this will help with determining what it could be...

if it grinds slightly with the other gears at full stop, engine running, then it has to be something either MC or Bearing as mentioned, if all of them are smooth and easy, then more than likely it is your 1st gear syncro....

 

when was the last time you changed your tranny fluid?

 

Less than 3,000 miles ago, in March.

 

Yeah. No problems with other gears - whether moving or stopped. The reason I was thinking it WASNT the 1st gear synchro was that it doesnt do it all the time, jut here and there. I imagine once the synchro goes bad, its bad?

 

How "sharp" is the shifting into any other gear? and is there any slop in the shifter when in gear?

Maybe order the marlin ball and seat kit to see if sharpening everything up on the shifter helps at all. It's a lot cheaper than pulling the tranny

 

Feels pretty good when shifting into other gears - as good or better than any other trans. Ive driven. However, there is a ton of slop in the shifter in most gears.

 

I'd say change the seat. It should help. It almost sounds like a "botched" shift from the minute movement in the seat.

 

Especially with 185k

 

OK.

Well, I ordered the shifter seat and socket from Marlin - so I'll get the cheap and easy solution out of the way first.

Conicedentally, I took my clutch lever out to fix the clutch squeek and since I put it back over the weekend, I havent noticed any of the grind I posted about. But its only been 25 miles or so - could just be a fluke.

Once the seat and socket come in, I'll throw them on and see how things go. If that doesnt work, I'll start looking toward the T.O. bearing.

 

The fluid you used, was it GL-4 or GL-5?

You need GL-5 for the trans. The GL-4 will eat away at the brass synchros in the trans.

I suggest you use Redline MT-90 fluid.

 

I used Mobil 1

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 all around - which is a GL-5. Aside from this issue, the tranny shifts very smooth. I would never tell it has 185K miles on it if I didnt know otherwise. And the shifter slop had never bothered me before.

 

Just an update:

So, I ordered the Marlin seat and socket when I originally made this thread a few weeks ago. For some reason it took a long time for the pacakge to arrive from Marlin - almost 10 days or so.

In that time, I pulled the clutch pedal assembly to replace the squeaky bushing and it turned out my clutch pedal assembly has no bushing (not that it was missing it, but that it didnt seem like it came from the factory that way). Anyway so I lubed up the spring part of the assembly and re-installed it. That did wonders for my squeaky pedal.

However, whether it was because of the lube or just because taking off the pedal assembly and re-installing it cleared some obsturction to clutch engagement, my grind into first has just about disappeared.

I did install the Marlin seat and socket and noticed a significant firming up of the shifter. For $25 or so, I would recommend that everyone get it. Ive put about 600 miles on the truck since I installed it a week or two ago and have no complaints - installation was super easy except for the fact that you need to ensure to clean off the gunk and grime at the base of the shifter mount so that the socket can firmly plant or else you wont be able to get the shifter back on. It took me 5 tries in the dark before I wiped down the area and click the shifter went in smooth.

 

You sure you got that right? Everything else I'm reading is saying GL-4 not GL-5

 

Yep, that's backwards, GL-4 is the "brass" friendly lube not the GL-5, although my manual says either or but to be safe, I always use the GL-4. I second the Redline MT-90.

I also think the issue is in the clutch or slave cyl. the adj side of all the slack put to specs.