3rd gear grind on my 6 speed

I've got a 2005 off road with 6 speed manual with 114k. If I shift from 2nd into 3rd too quickly, I'll get a grind. It's been going on since about 100k. I've noticed if I shift a lot slower it wont grind. My question is, am I causing harm by doing this? Also this is a very jerky shifting truck, is this normal with this tranny? And yes I changed the fluid.

 

Having the same issue with 3rd as well. It being jerky thats normal

 

How long has yours been doing it?

 

about 10k. Started when I missed grabbing a gear quickly

 

Syncro is worn. Shifting slower or double clutching that shift will eliminate the grinding. Otherwise you need a new 3rd gear syncro.

 

The Synchronizers on these trucks are poor at best.

 

I may have to invest in some tranny work then... The slow shifting is driving me crazy!

 

Yeah that's a good idea, replacing the synchros is much cheaper than the gears themselves.

Be ready to get raped on labor though.

 

Yeah, I figured it wouldn't be cheap. That's why I've put it off so long.

 

If you have the means to remove the transmission yourself you could save some money. I'd throw a new clutch in it too.

 

Maybe I can cash in some favors with one of my buds that knows what he's doing. I don't mess with transmission work

 

Mine does this too, but pretty much only when it's cold. I can avoid it if I intentionally shift much slower. After a few miles, it's not an issue. I have 159,000 miles on the truck, and I do notice it more now, so I do think it is a wear issue.

I would try changing the transmission fluid first. If the new fluid didn't help, then I would consider tearing into the transmission.

 

What gear oil did you put in? My six speed would grind 4th nearly every time as if it had no synchro at all when I had GL5 stuff in there. Even with light shifting pressure!

Doesn't fix the weak synchro issue but if proper oil would help even a little it could stretch its life out.

 

I've had smoother shifting with Red Line MT 90.

 

would you try grabbing 1st at 60mph even though the truck screams in terror?

if it grinds, don't do it.

apparently, either you or a previous owner dusted the synchro shoving it into 3rd when it wasn't ready. by shifting too fast, it was up to the synchro to try and match shaft speeds. now, its about tired of it and is making you slow down till the shaft speeds are closer together before it lines things up for you; which is when you should be shifting anyway. if you time them right, its not jerky.

clutch in when rpm is at its peak and just ready to come down (foot off gas)

slide into next higher gear with gentle pressure. you will learn to anticipate when speeds are close enough for an easy shift

clutch out when rpm falls to what it would be if you were driving the speed you currently are, in the gear you just shifted to. (that makes wayyy too much sense).

it could be your gear oil too. people often (myself guilty) throw gl5 into a trans that asks for gl4 assuming it is better. . . .well, from what I hear, it wants gl4 because that is the grade with the proper friction coefficient on the synchros to operate them correctly.

I don't think you need to pull the transmission. it will still last forever, its just asking you to better time your shifts for the rest of its life

 

After doing some research I changed the oil to redline mt90 a few months ago. It helped a little, but didn't eliminate the grind. I know how to drive my truck, my driving habits are not an issue.

 

If you are doing a clutch in the near future , its not a difficult task to install a new 3/4 synchro being at the very front of the gearbox . These transmissions come apart fairly easy . Take the two halves apart and mount the middle cast iron spacer in a vice .Once the housings are split , removing the shift rail and input shaft is a breeze . No gaskets at all , just high temp RTV is used .