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Old 02-24-2012, 03:42 AM   #1
Big-foot
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4 speed SM465 just lost reverse

70 4x4 Blazer 350.

At least it got me home first. Backed in, unloaded and pulled forward and that was the last time I've been able to get it into reverse. I can't even get close to engagement, the lever won't go any farther to the right than 3rd and 4th, feels like it's hitting a wall. I can get into all forward gears, motor running or not.

Is it dead?

Last edited by Big-foot; 02-24-2012 at 04:06 AM.
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Old 02-24-2012, 10:26 PM   #2
rsavage
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Re: 4 speed SM465 just lost reverse

Put the shifter in neutral and pull the shifter out to check the end of it to see if the end is bent/breaking. In case you haven't removed the shifter from the top of the transmission, you pull the boot, make sure it is in neutral, press and hold down the ring that the shifter goes through and while your holding the ring down turn it about a 1/4 turn and the shifter will pull straight up. Can't remember whether it is a 1/4 turn counterclockwise or clockwise, but you can figure it out.
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Old 02-25-2012, 11:57 PM   #3
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Re: 4 speed SM465 just lost reverse

Unfortunately the stick looks straight. The tip has 1/4" play left/right and up/down. Is that excessive?

I'll look down into the trans tomorrow when I can see better.
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Old 02-27-2012, 10:54 AM   #4
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Re: 4 speed SM465 just lost reverse

Put the shifter back in and try again...maybe just re-seating it will change things? If it's not bent..
my 465 has alot of play in there so...?
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Old 02-27-2012, 06:00 PM   #5
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Re: 4 speed SM465 just lost reverse

I have reverse! For now.

I squirted a quart of 10/30 all around the top but one quart was all it took. I was hoping that low fluid might have caused the problem but I don't think being less than a quart low would starve it like that.

I stuck the stick back in and drove it around in circles and to my surprise I can work it into reverse with some effort. I still can't go straight over, it's notchy and I have to go partially into 4th and then up and right to get around whatever is blocking it and then down into reverse. But I can get there.

I had no choice but to drive it to work Monday so I put a 'NO REVERSE" sign on the mirror to remind me to park so I can drive out again. I think I'll leave that sign on there for a while just in case.

The daily driver truck has a cracked block and I've been putting it off, I think someone might be telling me to get on it.

Thanks guys.
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Old 02-27-2012, 06:50 PM   #6
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Re: 4 speed SM465 just lost reverse

Hmmm I run 90w gear oil in my 465
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Old 02-27-2012, 07:29 PM   #7
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Re: 4 speed SM465 just lost reverse

It has a fill plug in the side. Put 90 weight gear oil in it until it is even with the fill opening.
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Old 02-27-2012, 08:16 PM   #8
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Re: 4 speed SM465 just lost reverse

Sounds like a shift fork issue to me. Bent, broken or worn.
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Old 02-27-2012, 10:44 PM   #9
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Re: 4 speed SM465 just lost reverse

Any metal shavings in the fluid?
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Old 02-27-2012, 11:00 PM   #10
Big-foot
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Re: 4 speed SM465 just lost reverse

Quote:
Originally Posted by cleszkie View Post
Sounds like a shift fork issue to me. Bent, broken or worn.
That's not good. Makes sense though. I'm pretty easy on trannies but I've only owned this truck for a year, no telling what it's been through.

I live way out in the country and 10/30 was all I had. I'll get some gear oil soon, pull the pan and check for shavings.
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Old 02-28-2012, 05:12 AM   #11
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Re: 4 speed SM465 just lost reverse

What pan? Drive it around and get the trans warm before pulling the drain plug. That way the fine particles are suspended in the oil. Stick a magnet in and see if u get any prizes! Get your wifes nicest measuring cup and see how much comes out
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Old 03-03-2012, 06:16 PM   #12
Big-foot
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Re: 4 speed SM465 just lost reverse

Screwy thing. After my last post it became difficult to get into 3rd and 4th. Feels like I'm shoving the stick through a piece of carpet. Matching the revs didn't help. Once I'm engaged it's fine.

Seems like every time I replace the stick it changes. I got home Friday and swapped out the oil, the magnet found only one shaving. I pulled the stick again to make refilling easier so I'll find out what it does when I drive it out to the shooting pit Sunday.

Gotta get that other truck on the road.
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Old 03-15-2012, 03:58 PM   #13
Big-foot
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Re: 4 speed SM465 just lost reverse

Looks like the plastic o-rings on the bottom of the stick were getting progressively worse.

Towards the end all I had was 1st and 2nd and the rails were all lined up, that's what told me it was the stick and not the tranny. Pulled the tip and the plastic was almost gone so I put three wraps of electrical tape around the top and bottom to tighten it up temporarily and made it 75% better. I just put some o-rings on it and it's still about 75%, I'll have to find some bigger o-rings or just weld it solid.

The ball is still tight and the sleeve below it has a tiny bit of play.

Anyway, looks like I found the problem. Thanks fellas.
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