Oil recommendation

[Northern lights]

OK, so I have a seal coming tomorrow for my Rockwell t221 (thanks guys for the ID) and can't imagine there being a problem filling it with 75-90 synthetic as I do with all my diffs but, rather than assume, I thought I'd get some thoughts on it. Also, out of curiosity, the 4spd tranny in my truck has the following markings on the drivers side right above the PTO cover. What would it be?.

A66
8
GM
837334

Thanks
C

[j.kirn]

Are you asking what kind of transmission. If you are it should be a sm-420, 4 speed. We know your truck now has the right transfer case which is original kind for your truck. Personally i dont believe in synthetic oil or the cost of it. I would use what it had in it and change it at the correct scheuled intervals.

[Yukon Jack]

What is the shift pattern of your transfer case? Reverse down and to right of 4th is an SM465.

[Northern lights]

Reverse is far left and back (left of second). As far as synthetic oil goes, It's the only gear oil I'll run in the peterbilt, western star and LTL9000. They all have 46,000lb rockwells. I use it because when the mercury dips to -30C or colder (winter before last we worked over a week where the temp never got better than -40 and spent alot of the time at or under -50 ambient, no wind chill) Mineral oil is no longer oil. Even synthetic is thick at those temps. While it's true that my '64 won't be seeing anything like that, it's the oil I have on hand so, to keep things simple, I'ld like to use one gear oil in all my boxes if possible. At this point I'm not sure I can get the yoke off without wrecking it and am not going to go any further until I find a source for a replacement should this one come off "modified".

[j.kirn]

You have a sm-420 , which is also original to truck

[Northern lights]

Thanks j.kirn. Any thoughts on getting a yoke off my T-case?. I have a puller on it and wound REAL tight but nothing. I'm afraid of snaping an ear off the yoke. Tried heat (breifly) but it seem that the dust guars prevents much heat from getting to the yoke sleeve so I decided to hold off on that for now.

[j.kirn]

The only thing i can think of is what you have done already. If you break the yoke they can be replaced. Sorry i couldnt be of help if i was there maybe i could.

[j.kirn]

I forgot to ask is your truck 3/4 ton or 1/2 ton

[Northern lights]

It's a 1/2 ton short box (originally 2WD) on a shortened mid 80's (I believe) frame. I've been looking but, as of yet have been unable to locate a new yoke. If I could find a new one, I could be a bit more forceful. I just got off the phone with my brother (HD mechanic) and he suggested haveing someone put an air chisel with a blunt bit up against the side to rattle the shaft and hit the end of the puller with a 4lb hammer. Might work. Do you know who carries yoke for this?

Thanks
C

This is the truck. Nothing special compared to alot of the rides on here but I like it.

[j.kirn]

I will check on yoke i had mine rebuilt in st.louis mo. i thought novak had them. Good lookin truck check out my 1960 k-20 restoration. All original napco axle on front.

[Northern lights]

Originally Posted by j.kirn

check out my 1960 k-20 restoration. All original napco axle on front.

Would love to. Where would I find it??

[j.kirn]

In the 4X4 projects and builds

[Skirkpat]

Originally Posted by Northern lights

It's a 1/2 ton short box (originally 2WD) on a shortened mid 80's (I believe) frame. I've been looking but, as of yet have been unable to locate a new yoke. If I could find a new one, I could be a bit more forceful. I just got off the phone with my brother (HD mechanic) and he suggested haveing someone put an air chisel with a blunt bit up against the side to rattle the shaft and hit the end of the puller with a 4lb hammer. Might work. Do you know who carries yoke for this?

Thanks
C

This is the truck. Nothing special compared to alot of the rides on here but I like it.

I like modesty, but not as much as that truck !!!! It is a beutiful ride, and as nice as 99% of any I see on here.

[OldCreek]

Those turbine wheels are SPOT-ON for that truck .... don't ever change em!

[Northern lights]

Originally Posted by j.kirn

check out my 1960 k-20 restoration. All original napco axle on front.

Now that's my kinda truck. Nice, clean straight truck. Nothing radical. Look forward to seeing it finished

BTW, I found a source for a yoke (should I need one). Hopefully I won't need it.........$200!.

[Northern lights]

Thanks Skirkpat & OldCreek. I'm kinda "old school" and don't mind a few mild mods but not into the tricked out stuff so much. Have a few things I want to do to it yet, waiting on parts.