Transmission issues.

[NCSUDucker]

A little background. Picked up the 39 1 ton in July of 24 after a fair amount of work to get it back running, it was serviceable but pretty low compression overall and 2 cylinders real low. It had been sitting for about 10 years. One of the other issues were the transmission had a significant amount of water mixed with the fluid. That was one of the first things changed. While we were chasing "vapor lock" that turned out to be an issue with a liner flaking off in the fuel tank, the truck sat outside for the better part of a year. Fast forward to Match when I got it back and began driving it around. It would fire right up but low power and would smoke you out of the cab, so I decided to drop it off to be rebuilt as that was out of my scope. However I found a mildly built 59a motor up in PA abs decided to go that route. Motor installed with a new clutch. Drove it a couple of weeks and started to grind a little even going into first at a complete stop. Adjusted the clutch linkage a little and it shifted like a charm with absolutely not even a chirp between gears double clutching. Probably about 500 miles since this, now it's wanting to grind a lithe between 2/3 and 3/4th no problem going into 2nd or reverse at a dead stop. I don't use first with it being the granny. I checked the transmission oil and it was a little milky so I drained it and refilled with 90w gl1 (it was 140 but no one had it in stock, plan on changing again soon) However, there was a ton of water in there again. Is there some kind of boot on the shift lever that might be worn out that let's water enter the transmission? It's stored indoors or under a cover now. Secondly I tried adjusting the linkage again but can't get the grinding between 2/3 and 3/4 to subside. Any suggestions? Wondering if the water intrusion might have caused some kind of damage.

Thanks for all the help you guys give in advance.

Brad

[cas3]

Have you got the proper 1" of free play at the clutch pedal? Clutch could be not fully disengaged if so. No seal at the shift tower, once drained it should not get water again. Might have bad bearings if its had water for quite awhile.

[NCSUDucker]

Originally Posted by cas3

Have you got the proper 1" of free play at the clutch pedal? Clutch could be not fully disengaged if so. No seal at the shift tower, once drained it should not get water again. Might have bad bearings if its had water for quite awhile.

When you say 1" of free play, are you talking about from the floor before the clutch starts to disengage or from the top when the clutch starts to engage? Mechanic said the linkage may need to be adjusted a few times as the clutch breaks in.. i didn't have any problems after i first picked it it up. Then it wanted to grind just a bit, even going into 2nd at dead stop. I screwed the linkage out about 1/4" which was perfect for about 500 miles.

[flatford8]

1” of freeplay at the top. When you push on the pedal, it should get stiffer or harder to push after 1”. You could pull the shift tower off and have a look inside. If there was a lot of water in it to start with, you may have to change it a couple of times to get all the milky stuff out. Or you could have some rust on parts that’s causing your problem……..Mark

[38 coupe]

The early four speed "granny gear" transmissions have no synchronizers in them. Double clutching (or floating the gears if you are really good) is required to avoid grinding when shifting up or down.
I'm guessing the transmission had a good bit of sludge and a bit of rust on the gears and shafts when you started driving it. That created enough drag to make shifting easier, the gears would slow down on their own while you shifted. Now that you have driven the truck and changed gear oil again you have cleaned out most of that and things spin more freely. Now you have to double clutch to shift without grinding.

[Mac VP]

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Since there are no synchronizers in the truck 4 speed transmission, they will really benefit from using the heavier 140wt gear oil. This will help slow the spinning gears down sooner than the 90 wt oil….very helpful when up shifting.

If stored inside, there shouldn’t be any water leaking into the transmission. Perhaps you didn’t get it fully drained before. If water has accumulated inside the gearbox over time, chances are that there may be some pitting of the lower gears inside. That may or may not have weakened the gears, but it’s certainly not good for the bearings. With the straight cut spur gears in this unit, it’s never going to be a quiet gearbox but pitted gears and rusted bearings will add to the racket. None of this affects the shifting performance issues however.

[NCSUDucker]

Originally Posted by flatford8

1” of freeplay at the top. When you push on the pedal, it should get stiffer or harder to push after 1”. You could pull the shift tower off and have a look inside. If there was a lot of water in it to start with, you may have to change it a couple of times to get all the milky stuff out. Or you could have some rust on parts that’s causing your problem……..Mark

Thank you. I had read about the 1" of free play but wasn't sure whether from the top or the floor.

Originally Posted by 38 coupe

The early four speed "granny gear" transmissions have no synchronizers in them. Double clutching (or floating the gears if you are really good) is required to avoid grinding when shifting up or down.
I'm guessing the transmission had a good bit of sludge and a bit of rust on the gears and shafts when you started driving it. That created enough drag to make shifting easier, the gears would slow down on their own while you shifted. Now that you have driven the truck and changed gear oil again you have cleaned out most of that and things spin more freely. Now you have to double clutch to shift without grinding.

I have always had to double clutch in it, even before the new clutch was installed. I'm just trying to figure out why I had only the occasional grind when I missed the correct RPM double clutching when I first got it back from the engine being installed, to absolutely zero grinding and smooth shifting when I needed to adjust the linkage (again still double clutching), and now grinding a bit between 2nd/3rd & 3rd/4th pretty much no matter how well I time the RPMs on the shift.

Originally Posted by Mac VP

Since there are no synchronizers in the truck 4 speed transmission, they will really benefit from using the heavier 140wt gear oil. This will help slow the spinning gears down sooner than the 90 wt oil….very helpful when up shifting.

If stored inside, there shouldn’t be any water leaking into the transmission. Perhaps you didn’t get it fully drained before. If water has accumulated inside the gearbox over time, chances are that there may be some pitting of the lower gears inside. That may or may not have weakened the gears, but it’s certainly not good for the bearings. With the straight cut spur gears in this unit, it’s never going to be a quiet gearbox but pitted gears and rusted bearings will add to the racket. None of this affects the shifting performance issues however.

Thanks Mac and appreciate the input, I figured as much but could not find the 140 locally. I should have some here today and will see if that helps. Just to clarify, the transmission fluid was changed when I first bought it but while we were chasing other problems it sat outside at the mechanics on and off for about 8 months. Now that I have it back it will be indoors or at minimum under a cover. My biggest concern was how it was getting in as it wasn't a small amount like condensation. I don't know the exact amount of water but when I removed the drain plug it came out more like water than gear oil and even shot past the bucket i had placed under it.

Thanks again for all of the input. Wish I had more to offer here than posing questions...lol

Brad

[slowforty]

check the model a forum. they use 600wt inthe trans

[v8fordman]

You need to drive across the river and get you a spare transmission. Just in case you have damaged gears.

[NCSUDucker]

Originally Posted by v8fordman

You need to drive across the river and get you a spare transmission. Just in case you have damaged gears.

You happen to have one? Back to shifting good today after starting out with a few chirps between gears... really strange. However, on the downside, the starter went out today. Granted I've been running a 6v starter with 12v. Got a new Powermaster on the way along with a solenoid just in case. Still need to get the carbs dialed in starts great when cold but wants to load up a bit making it hard to start if I try to fire it right back up after I've been running for awhile. The plan is to replace the starter and change the transmission oil with the 140 wt and have it for the opening day off dove season here to make for some cool pics. Then drop it off at the mechanic to tune the carbs. However would love to come across the river some time to put a face with the name! Slowly but surely everything in the truck is going to be new LOL

[v8fordman]

Come on over. I may have two 4 speed transmissions. I would have to look.