Brazos

Hi all. I just bought a '93 4wd Toyota truck w/ 184K miles on it. I have not driven it much in the week that I have had it but the transmission and transfercase/4wd seemed to work perfect prior to purchase with no fluid leaks on the truck. Just to be preventative I planned to change fluids in the tranny/T-case/and front/rear differentials (previous original owner said it had never been changed). Today I started with the Transmission and transfer case oil changes. I started with the transmission. Per my Chilton & Haynes books I drove the truck about 3-4 miles to warm up the transmission. I drained the oil and filled it back up. I found the oil level a little low and a little dirty. There was a little sludge on the drain plug but nothing crazy. So then, per the book, I put the truck in 4wd and drove a few miles and came back and changed the T-Case oil. The T-Case oils was a little low but nice and clean. I did find a few small metal shaving on the magnetic plug, again nothing crazy. I was feeling good about things knowing I had nice new oil at proper levels. Here is what I noticed. I now have a whining sound from the transmission. Not bad but it wasn't there before. I also have this constant (always there with no noticable change in pitch) high pitched whinning sound (not super loud but noticable) I believe from the T-case. FWIW I used oil I bought at Autozone which was Coastal 80W-90 gear oil that says it meets SAE GL-5, GL-4, & GL3 ratings. According to both books this was the proper weight oils for both the Tranny & T-Case. Chiltons said GL4 or GL5 for both the Tranny & T-Case and Haynes said GL4 for the Tranny & GL5 for the T-Case. Since this oil said it service both GL5 & GL4 (and is what Autozone had in stock) I figured "what the heck it has 184K miles". What could be causing these new sounds and should I be concerned? Other than the new noises it seems to function just fine. Could it be the new oil just stiring up left over sludge that is now being distibuted thru the gears?

On a similiar note the books said to use Hypoid type gear oil for the differentials. I bought some Vaveline gear oil that met that description (Hypoid). Changing that tomorrow.

Thanks,

Brazos

4bangercraig

Not totally sure about the whining, but I do know that 4 wheel drive on dry, paved roads is a major no-no. Binds your driveline and can end up causing your TCase to literally explode. When I did my TCase oil, I took it to a dirt lot and drove figure eights for a while to warm it up. Never seen it go down, but I've read that if your driveline's bound up, you can relieve pressure by jacking up the back end. Also read that sometimes the consequent backwards spinning of the tires will throw the truck off the jack if it's bound badly.
Wheels need to turn at different rates going around turns. In a low traction environment like dirt or a really rain-slick road, side slippage allows this to occur. On dry pavement, the wheels are forced to turn at the same rate. The wheels attempt to turn at different regardless (because physics forces them to). The resulting pressure is absorbed by the transfer case and it's bad news bears.

Sorry if I misread your post. Just wanted to save your driveline!

Brazos

I hear what you are saying 4bangercraig. I was just doinf what the book said and took it real slow and easy. Especially on the turns. I am done working on the truck for today but think tomorrow I will recheck the fluid levels. Even though I filled to the point of fluid running out I was still about a 1/2 quart short on the tranny and about 3/4 short on the T-Case as what the book said the capacities were.

highonpottery

iTrader: (1)

could it be possible that the oil you took out was heavier weight than the stuff you put in? i know that for my truck i had the tranny rebuilt because of input bearing noise and i still had a little after the rebuild. the solution was to put heavier weight Redline gear oil in the tranny and everything has been good for the past 2yrs. since you weren't able to get the full capacity of oil in there, was your truck on level ground?

driving on the dry pavement was probably ok as long as you're not doing it a lot and with lots of turning. whenever i run my 4wd on pavement to get the oil moving around i don't lock the hubs, thus the wheels aren't technically tied into the drivetrain and still allows the parts to move without worry of binding.