Tranny question

[huskilvr]

Hi,

Changed out transmission fluid in my 66 4 speed, and used 50 wt motor oil. Is this ok or should it have been 50 wt tranny oil? Getting a sound now when truck is moving like chain rattling or spray can shaking type noise. Doesn't happen in neutral just in gear. Thanks!

[oldtrucks]

Should use 80/90 gear lube sounds like you have some bearings that are worn and allowing some shaft movement. Drain and refill with the heavier lube and add some Lucas additive and if the noise continues you will need a rebuild kit. There are several very good gear people in Seattle to help you. Check with the local salvage yards for a good used tranny. Do you know which tranny you have, T-18 or the 435. If reverse is over and down it is the T-18, over and up is the 435. Both good trannys and not hard to rebuild.

[texaskicks]

Second the hevey gear lube. Also if that does not solve the noise issue besure to check that your clutch is set up correctly, but like the above said more likely internal.

[huskilvr]

Thank you for your help!

[cdherman]

50w engine oil is about the same viscosity as 80-90wt gear lube. I know -- it makes no sense.

[huskilvr]

That is weird! I read that while the same viscosity gear lube reacts differently to heat and pressure and has different additives than motor oil. But don't know if that makes a huge difference?

[blackagatha]

I dont know what difference the stuff in the gear lube makes other than being a nice slippery, slimy mess in there keeping everything all happy.

The biggest difference that I can come up with is that the stuff STINKS and doesn't wash out of your clothes. Even 50wt engine oil washes out nicely, but I got a big old diarrhea squirt out of my 3speed when I was doing my engine/trans swap, right on the chest, that shirt with the crap on it went thru the washer like 10 times before the splat quit stinking, and the fabric is still strange feeling.