Change all fluids? (2 Viewers)

[Scota4570]

My 1970 is getting more road worthy. It does make some odd vibrations and general lack of smoothness noises in the drive train. As far as I know the none of the fluids have been changed in decades. I changed the oil and flushed the cooling systems yesterday. What about the diff, gear box, transfer case, steering box, winch and so on? Should I drain them all and put new gear oil in everything? I am suspicious that some of the noise is from low levels or worn out lubricant. Should I be putting any additives in anything?

 

[brian]

while some might be due to lack of fluid, possibly. chances are better that either you are not familiar with 40s, or bearings are shot.

 

[firemanj92]

Yes, change all fluids. Your 70 should use 80w-90 GL4 gear oil with no additives in the trans, front/rear diff's and transfer case.

 

[ceylonfj40nut]

Absolutely. Inspect all drained oils for shavings and flakes. If you have water or milky oil, likely water.

 

[Scota4570]

OK, Sounds like a plan. I'm pretty familiar, I have been driving it since I was 10YO. It is definitely worse.

I have found a place that will clean the undercarriage for a price that I am happy with. I'll change out all the fluids then, clean and assess. One challenge is that no shops in my area are interested in it or will work on it. There is one guy who now works out of his house. He may be great, then again that is how my father got burned multiple times.

I am surprised and annoyed that virtually no shops will work on old cars any more. I understand that the need to assess the customer and the expectations. I will pay a fair price and expect other issues to arise. $200+ an hour for labor is the same regardless of the age of a vehicle. Maybe most modern auto tech don't understand old vehicles and rely on scan tools and computers more than mechanical ability?

 

[Paul_A]

Don't forget to grease those drive shafts and front end parts, too.

 

[sogncab]

It'the hardest part about changing axle, differential, tranny, and tcase fluids is putting it back in. I bought a little pressure pot off Amazon, and that made out much nicer.

As far as noise, these things never had much in the way of operator comfort in mind, and a lot has been learned in 70 years for fluid dynamics.

Rebuilding everything, or having everything rebuilt is money well spent in my opinion.

 

[Zjohnsonua]

I'd plan on two drops. That fresh oil is gonna knock all kinds of stuff loose. Let it do its thing and then repeat the drain and fill

 

[SteveH]

I would drive the truck to get it hot or warm (as much as possible) and stir up contaminants in the axles and gearbox, then drain fluids and refill. Skip the additives.

Do you really want the 25 year old tech at most 'modern shops' to try to figure out how to change a thermostat with a (gasp!) paper gasket, and clean the surface properly without gouging it, and reassemble with a light coating of FIP? I didn't think so.

 

[South Texas 97]

I always take out the fill plug before the drain plug, it helps the flow, and you know you can put fluid back in. ditto on getting it hot and agitated before draining.

 

[sogncab]

Buy the updated fill and drain plugs too. They aren't expensive, and easier to contend with