I recently flushed out my tranny oil out of my 87gxl n/a, and what i saw made me wonder. I was having symptoms with my tranny ie: it was hard to shift, i would trip certain gears at certain times, yadda yadda yadda. But my question is what would turn transsmion oil into something black and really frothy? If anyone knows it would be very helpful in an effort for me to make sure I don't have to repair my transmission beacuse of this problem later on. (I already put new tranny lube in so i should be good until i load up the good stuff: redline, royal purple, etc. which I imagine happening relitively soon)

I searched for frothy tran but nothing came up, so help a brother out.

 

Frothy = Overfilled
Black = Burned or Clutches Coming Apart...

 

eww....:-/

 

Was it ever run low on fluid? If it was you'll have gears that whine because the bearings were cooked and are no longer perfectly round. When that happens you get black tranny fluid.

 

Excessive moisture and heat related fluid breakdown will cause both.
Fluid and additive breakdown from excessive time usage, and too many miles or years. Heat is caused by incorrect fluid, low oil level, and spent additive package.
Moisture buildup from an excessively long change interval and by leaking seals. How much condensate or rain can enter a transmission from the shifter area? Was it ever parked in flood area?

What brand gear oil? what mileage interval?

Before switching to the good stuff, which you should've been using and maintaining regularly anyway, consider flushing that manual transmission. You might want to change the transmission oil again in 500 miles to see if it washes the transmission. If the new gear oil comes out dirty again, you will need a solvent to clean up the transmission.

 

I do not believe the car was parked in a flood zone. I think it was just never changed in the life of the car. there are no leaks or places where rain water can enter the tranny directly from where I've been able to inspect. I will be going in for a tranny flush in about 2-3 weeks. considering I have only been the owner of this vehicle for the past month or two (probably the exact date is my join date on this forum) I have taken pretty good care of it for routine maitenence. anything prior to that date I do not know so much. total miles on the car are 105000, with an engine swap occuring *i think* at 35,000 (i'd have to check the recipt to be certain). if that was the last time the tranny fluid was flushed (i do not know, is it SOP to flush the tranny during an engine swap?) that means the car was driven like that for 70,000 miles. I believe haynes says to flush and fill after 50,000.

If that's the case then it was 20,000 miles over due. There also seems to me evidence that the shifter has gone through some abuse (indicating rough shifting/driving). when purchased there were no bushing remaining in the shifter. I have since replaced the missing lower bushing and have been time hungry to go out and purchase the upper bushing and spring washer.

 

Gear oil expands when hot. Air is burped as the tranny heats up. As it cools, any air drawn in will have moisture. Flood or not, leaks or not, moisture can enter your transmission over time.
30k is a reasonable life for any gear oil.
Please don't quote the Haynes. Its a good do it yourselfer book and nothing else.
And, if the wrong fluid is used for the topoff or tranny change, then its overdue the minute its installed.
Don't assume gear oil is changed at an engine or even clutch replacement, unless there are records to prove it. Sorry, but too many owners and shops cut too many corners.

So, what gear oil did you use in your manual transmission for this rinse?
What gear oil do you plan on running long term and for future maintenance?

If you bring you own gear oil to a shop, make sure you watch them install it.