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1967 c 50 2.5 ton dump truck:
Just changed the tranny oil & used 80/90 wt. Trans was whining & still is after the oil change. Actually, there was like NO OIL in the tranny as I found out after removing the drain plug. Not good. I'm considering going to a heaver wt oil. Anyone done this b4? Also "Lucas" makes a good additive. According to the directions, Lucas can also be used be used straight (as a non-additive) where heavy wt oils are used. Thoughts? Any & all imput appreciated. Oh also, it looks like the old oil was lost from a leaking seal.

CFFC
Don

Heavy oil or additives will not stop the whining although it wont leak out as much. If it whines in the lower gears but not in high it has some bad bearings. If it whines in all the gears & changes from acceleration to deceleration it might be in the rear end. A steady whine most audable at low speeds can be the carrier brg. in the driveshaft.

It the truck was driven much without lube in the transmission the bearings are suffering from excessive wear. If I were you I would rebuild that transmission before you have a catastrophic failure it is getting tuff to find gears for some of these old transmissions. You should be able to find some one to rebuild it for 4 to 6 hundred if it’s just bearings and a synchronizer ring or two but may become very expensive and near impossible if you damage any gears or shafts.
I concur with Wrenchbender lubrication is preventative not a cure no oil will fix damage.

try running 85w-140 it won't be a cure all but it will take some slop. basicly buy you time. . .

Those are pretty easy to o-haul yourself as trans. go. Get a good book & go step by step.

I'd rebuild it brake it in than fill it with
80W-140 synthetic gear oil.... I used AMSOIL in mine worked out well no leak's smooth silent shift's. . . i was told i would have gear noise but there is non. . .

Just got in from riding her for about 15 miles. Whining is definitely in the lower gears (1st & 2nd) when upshifting. Also whines when downshifting (3rd 2nd 1st) mainly 2nd & 1st gears. When driving speeds between 40 - 45 mph there's another sound. It almost sounds like a jet. Any clue what that may be?
Looks like it about that time to drop the tranny. Aside from zero tranny repair experience, the biggest concern is finding replacement parts. Any idea where new bearings & bearing races can be purchased? ... & where can the special tools needed to do the job be purchased? Possible carrier bearing too. Is the carrier bearing in the rear end?
Also, during this truck's life it had a 350 put in it. At least that's what the guy who sold it to me said. How can you tell? Does it use the same spark plugs as stock engine? If so, that may indicate something. Also, if it turns out to be a 350 engine, would the tranny have to be different?
Perhaps worth of mention; About 8 months ago when I bought her & drove her home, the following day I found that one of the axle plates & u bolt was broken on the drivers side. no too long ago I replaced the plate & u bolt. Is it possible that the rear axle is mis alligned? Woud that cause the jet sound? What the best way to check it? Thanx again.

CFFC
Don

Don,

In regards to the broken suspension items. I think even with only one U-bolt that the center bolt will hold the rear end properly in the axle pad. It would be real noticeable if it were even a smidgen out...while driving, look in your rear view mirror...if the back isn't following the front perfectly your rear axle is cocked. This shouldn't cause any sound.

Stuart

Dont know what trans your truck has, but a place called Novac had the parts for my 47. They have rebuild kits + their website as alot of good info. Hopefully if you punch in Novac it will come up. I did my sm420, first trans I had ever done. 400 miles and appears to be working well. Also check your rear end, if your trans was low maybe the rear end might be too. Mine was out of oil, or atleast it had been at some time or another,Expensive repairs.

If it were mine I would put a quart or two of Lucas or Hi-Tach in it, after draining out the same amount of the regular oil. Then I would drive it until you could not stand it.

In the mean time I would look for a second transmission, as this is almost always cheaper than rebuilding one, especially with a common one like you have.

By the way, what transmission do you have? A 4 speed, or a 5 speed. The 4 speeds can be found for around $100 or less in good quiet working condition. If it is a Spicer 5 speed with the round SAE 12 bolt clutch housing then I have one that I will sell for $75. It has about 85,000 miles, I drove the truck home and parted it out, it's easy shifting with no problems.

If you plan to keep the truck for ever, and just like rebuilding transmissions then do it. For a work truck, or anything less than a full restoration, buy a used transmission and save yourself the money, trouble, and time.

Grigg

After a lot of research & getting under the truck several times, It safe to say she's got the late sm420 trans w/the ribs on the right side of the case.

Grigg, thank you for offering the tranny. Pretty sure there was a previous thread regarding swapping a 4 speed for a 5 speed. Going to have to find that & see if that's a feasible option.

Tom, Do you recall what tools you used to rebuild your tranny? What information sources did you use to guide you through it? Even if I go with a tranny swap, it would be a good learning experience to rebuild the trans that's now in the truck. Especially during the upcomming north east winter. Thanx again to the "Big Bolters" for aiming me in the right direction

So you have the SM465. That's an excellent transmission too.

I would still recommend buying a used one before you rebuild yours. You will have more in new parts than a good reliable used one cost.

Grigg

If it,s a SM465 i,ll agree it would be better to get a used one. They are ornery to rebuild. Used ones are plentiful & generally good because they are a tough trans. They are pretty much the same from 68 up. Some of the big bolts had the e-brake behind it. Around the early 80,s up they had some improvments.

Pretty positive it's got an sm 420 trans. The pic of the sm420 on the Novark site is exact(horizontal ribs on passenger side).Also H shift pattern w/ reverse being in & down toward driver.

Not that it matters for the decision you have to make, but what model do you have?

You say late SM420 with ribs, to me that means SM465. The SM420 is the older version, first used in 48.

Grigg

1968 was the first year for the SM465.

That makes me wrong then. I thought it was somewhere about then. I'll edit my earlier post so as to not confuse anyone else.
Thanks,
Grigg

Shovelhead - Its Novak try their web site real good info. Their rebuild kit comes with all the bearings and new rollers and synchronizers. It was $198, the tranny shop wanted 800 plus to rebuild mine. Several of my friends - more skilled with more experience told me it was easy and maybe more important - they did not want to do it, so I decided to give it a try.
The web sight and instructions tell you everything you will need and are pretty good. Only things I needed were some cheapo pullers and a press 3 ton, from Northern tool. My friends said get a bigger one but it did the job and I am pressed for room. Some snap ring pliers are good to have too. Thats about it. I would not call it really easy myself - but it was not bad either. I had a harder time getting the tranny back in by myself than anything else.
I think the other guys might be right, my truck is kind of a beater and I am getting more in it then its worth, but as long as I can still pay for gas I will keep it.Mainly I like working on my stuff and trying to learn about it, not to mention - I cant afford the pro's help very often. In my area, the trans shops were telling me the 420's are getting pretty hard to come by. I dont know if thats right or if they were trying to stick me. I rode a shovel for 25 years, a Sturgis 81 - it was an excellent machine!! Good luck, Tom.

Tom,
My bust, .... "Novak" (not Novark) is what I meant. ty for correcting that. Excellent pics & info there. Right on about the shovelhead. We could really get into what makes that bike a great choice for ppl that do their own wrenching, but this isn't the right place. How often did you use the 3 ton press? Trying to figure how many trips to a shop for pressing will be needed vs. purchasing a press. Thanx again.
CFFC
Don

Don, I used my press a bunch - probably 6 times or so. Mainly just trying different sized snap rings and spacers - trying to get the best fit I could. You might be able to get by with less attempts. Mine was a cheapo from China and I have used it several times since. You might be able to get by with a small sledge hamer and a brass drifts or leaded steel drifts. But it says in the instructions that hamers are not recomended because the bushings in the 420 dint hold up well to sharp blows. So I felt better with the press. None of it is to much of a press fit, it comes apart pretty easy, Tom.