Well, glad I don't have a ranch. And, I posted after you posted your comment.
Hope you get it figured out. Good luck. Sandy

I'm not arguing the point but I am curious and to why you don't buy it being the problem. I thought the forks ONLY rode in the sliders and never touched anything else. That is why I buy into them causing the wear. I guess if the sliders were sloppy from wear they could slide into the forks some but I am not sure.

 

Just noticed that I never answered your question... The fork that was worn for myself and others has typically been the 1-2 fork. I know that I spend very little time in those gears, and I would think you need to be in those gears to wear the fork, no?

 

I would think so since MOST people are in 1-2 more than 3-4. I think the driving tendency is to take off in first and try to get to second to get up to speed as fast as possible. That fast shift to second would cause the fork to slam into the slider. With my M5OD and gearing I couldn't get over 20 or so mph in first. I wanted second as fast as I could to keep from getting run over. Third and fourth are Usually more relaxed shifts and are less likely to be jammed into gear. I also don't think many people take their hand off the shifter when the transmission is in first and second gear. These are the reasons I think driving habits contribute to excessive fork wear.

IIRC your 1-2 fork was replaced soon after you got your truck several years ago. We don't know the habits of the PO. Have you replaced it since? Sandy

 

Funny you should ask as the transmission is on the garage floor as I type this; not for an internal failure, but for a clutch replacement/upgrade to 11". That said, your question inspired me to go take the cover off just now. I am happy to report no wear on the 1-2 fork at all; in fact, there's barely contact marks on it. The 3-4 fork (the one on the right below) actually has a little radial wear on the left side - just enough to create two tiny ridges on the wider section at the top. That may very well have been there before - I'll have to check my pics from 2012 and compare them to these. (Edit - just looked at my pics from 2012 and I took my pics from the other side - the opposite of the ones below).

 

I think 1-2 fork wears more because you push the shifter harder to get into first gear from a dead stop. You push it harder because the first-gear synchro has to slow the output from 700 RPM (idle speed) to 0 RPM (wheel speed) before it can go into gear. The rest of the gears don't have as much of an RPM change between them. I guess technically you don't have to push it harder, you could just wait a couple more seconds for the synchro to slow the output shaft to 0 RPM. But I think most people just unconsciously push it harder.

Anyway, by pushing the shifter into first gear with more force, the fork pushes against the slider with more force. The slider pushes the synchro harder, which creates more friction and slows the shaft down.

Does that make sense?

Edit: The synchro doesn't just slow the output shaft -- it slows the output shaft, counter shaft, and input shaft. Basically everything in the transmission has to stop rotating before it goes into first gear from a stop. And the output shaft isn't turning at 700 RPM, it would turn at about 250 RPM because of the first gear ratio. Anyway, that is a lot of rotational energy that the first-gear synchro has to convert to heat (via friction) to slow the transmission internals to 0 RPM.

 

I don't doubt that user abuse is a contributing factor to fork wear. My questioning was more specific with regard to leaving your hand parked on the shifter as an arm rest as a cause of wear. With as little time as the transmission stays in 1-2, I would think that wouldn't be the specific cause.

With my transmission, my bigger concern was that something else was going on that was causing the 1-2 shifter fork wear I saw in 2012. ~10,000 miles later, my inspection yesterday alleviated those concerns. In fact, I'm MORE inclined to agree with you now that user abuse was the cause given that under my care, I have not abused the transmission, and there is no 1-2 fork wear at all.

 

Regardless of the reason I'm glad you're one two fork iis in good shape. Sandy

 

When I drained the fluid before dropping the transmission there was a fair amount of ferrous "goop" stuck to the magnetic drain, so I was a little concerned given that had accumulated with just 10K miles of use. I'm not sure how "normal" that is, but at least it's not a 1-2 fork about to fail!

 

I've seen the shafts bent enough from trying to jam in first, or third, and that caused it to touch almost all the time, and PO's not knowing you don't have to hold it in gear, in town driving made it worse, red light to red light

 

I suppose if the old 1-2 fork bent, that would have resulted in it wearing out in a hurry and would explain why the replacement one is doing totally fine.

 

This was your question. In looking at your older post, I don't see where you changed the fluid when you replaced the fork. If that is the case, the goop you saw on the drain plug was left over from the first one being worn out. All should be good if so. Sandy

 

I may not have mentioned it, but indeed I did change the fluid when I replaced the fork ~10K miles ago.

 

To the OP, can you list the part numbers of the shifter forks and maybe where you bought them? Thanks

VOTS

 

A lot of folks on here have used Allstate Gear. Here is their website and the parts they have for our transmissions. If your shifter is sloppy, a shift kit is available also that is easy to install and gets the shifter back to normal.

https://www.allstategear.com/Manual-...rts-s/1815.htm

 

sandymane, thanks for the response. I bought the shift repair kit and 5/8 metal plugs from Allstate in an attempt to fix the oil leak from the shift tower. That's when I noticed how worn my 1-2 shift fork was, it's about .040" thick. The 3-4 is in better shape but I'm going to replace both when I'm in there.

The pictures of the shift forks on Allstate's website don't match what I have on my truck. The pictures of the OP's forks match what I have, that's why I asked for his part numbers. My truck is a 95 and I've had it for 2 years. I'm wondering if the original transmission was replaced at some time. I'm going to call Allstate on Monday and see what they say.

Here's my 1-2 fork.



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