Transmission grinding in third etc.

[socom688]

So the third gear is starting to go in my deuce... My question to you guys is what exactly do you guys think is the problem. I think a synchro maybe?

Symptoms:

If I shift into third "normally", it will grind. However, when I shift slowly and let the rpms drop a significant amount (an annoying amount, it really slows up city driving), it will not grind as long as I gently, but firmly move it into gear.

second, when I have the steering wheel turned completely to the left, there will be a grinding noise until I press the clutch in, then no grinding noise.

I don't know if the symptoms are related, but I'm sure as **** hoping they will be easy fixes. Deuce funds are where they should be for a trans replacement.

 

[clinto]

1. Synchro is worn out. Need to inspect the gears to make sure they're ok.

2. PTO linkage is binding up when the frame flexes. As the frame flexes, the linkage is trying to push the PTO into gear. Next time it does this, instead of pushing in the clutch, reach down and apply pressure to the PTO lever. When you apply pressure in one direction the grinding will get worse and the other direction will make it go away.

 

[socom688]

Thanks clinto! I need to adjust my linkage on both my pto and transfer case anyways so that just makes sense.

Also, how hard/pita would a synchro change be? I don't have any kind of trans jack or anything like that. Would it be worth it to just find a used trans to put in there or take it to a shop for a synchro swap?

 

[gringeltaube]

You don't have to pull the whole transmission, if it only needed a new 2nd-3rd synchro.
There are many threads explaining the procedure. Here is one...


G.

 

[phil2968]

Instead of waiting for the rpm's to drop, do like the rest of us and double clutch. Once you start doing it you find yourself doing it all the time.

 

[socom688]

Ok, I did some driving today and double clutched it, only one grind, and I think it was diver error. I didn't press the clutch down on the second pump as much as I could have. So this will save me from getting a new trans for a bit. As far as the pto grind, I moved the pto lever during a left turn, and I still can't determine if it is the cause. I have to spend more on that later.

 

[socom688]

So I figured out that it IS the pto lever that is making the grinding sound during sharp left hand turns. It needs to be adjusted a hair. Thanks for the input Clinto!

 

[rustystud]

1. Synchro is worn out. Need to inspect the gears to make sure they're ok.

2. PTO linkage is binding up when the frame flexes. As the frame flexes, the linkage is trying to push the PTO into gear. Next time it does this, instead of pushing in the clutch, reach down and apply pressure to the PTO lever. When you apply pressure in one direction the grinding will get worse and the other direction will make it go away.

I have never heard of that before. That is really interesting that the frame flexs that much ! Might be another good reason to go to a hydraulic winch instead of the driveline.

 

[clinto]

I have never heard of that before. That is really interesting that the frame flexs that much !

This picture doesn't show the maximum frame twist that is possible, but it's a good example. From the 2008 SSGR.

Might be another good reason to go to a hydraulic winch instead of the driveline.

I guess you could look at it like that, but to me, it seems like a good reason to spend 15 minutes and $0 and adjust your PTO linkage.

I don't have a problem with hydraulic winches (I have a customer's M35A3 I am playing with right now and the hydraulic setup has some nice features), but I think the factory setup is fine. No need to redesign the wheel over a linkage adjustment issue.

 

[phil2968]

Clinto, remember when Gimpy got his truck all twisted up down in the canyon at SSGR09? There may be a pic in that thread. The cab and bed were a right angles to each other!

 

[clinto]

Clinto, remember when Gimpy got his truck all twisted up down in the canyon at SSGR09? There may be a pic in that thread. The cab and bed were a right angles to each other!

I looked all through that thread and the pics of his truck really didn't show how much it was twisted up. I did find this though:

 

[Jeepsinker]

Neato! I guess that is why our frames are riveted and not welded. I doubt the Air Force trucks would flex that well though because the beds are welded to the frame in multiple places.

 

[welldigger]

Neato! I guess that is why our frames are riveted and not welded. I doubt the Air Force trucks would flex that well though because the beds are welded to the frame in multiple places.

Sounds like a field repair someone did to me. My buddies a2c drop side bed is bolted on with the flex joints in the front just like my standard cargo bed.

 

[Jeepsinker]

Oh no man, all five of the ones I had here were like that, as well as an Air Force drop side five ton that we cut up here a few weeks ago. They are attached with pieces of angle welded to the frame and bed between each bed floor crossmember.

 

[welldigger]

Hmm that's interesting.

 

[The King Machine]

Here's my truck flexing out.
All 4 rear tires are on the ground

 

[rustystud]

Oh no man, all five of the ones I had here were like that, as well as an Air Force drop side five ton that we cut up here a few weeks ago. They are attached with pieces of angle welded to the frame and bed between each bed floor crossmember.

My M35A2C Air-Force rig is just bolted down and has the springs like any other deuce I've seen.

 

[mobileauto2000]

When I got my truck third and forth gear would grind. But mainly third. I change out the GL5 and went to 40w motor oil and it started shifting better and better. After a few weeks of driving there was no more grinding at all. The friction modifiers in GL5 can cause the syncros to slip to much and cause hard shifts.