Recently moved the car and saw a oily spot on the floor which would be from the rear end. First drip in 11 years of ownership. I have the car up on the Quickjack doing some maintenance for an upcoming trip so I rolled back to see a drop of fluid at the seam where the trans and diff bolt together. I was hoping it wasn’t the leaking butt issue, and it doesn’t appear to be originating from there. Any other likely culprits? Its fairly clean back there, meaning no long term leaks with caked on dirt and grime. It’s a 99 FRC with 81,000 miles.

 

Brown fluid or red fluid?

 

I wouldn't start to worry until there was a puddle

 

If the fluid has enough trans fluid in it to turn red he has a massive trans fluid leak from the rear output seal. Should only be gear oil from that seam unless its leaking elsewhere(tail shaft to trans joint) and blowing back.

OP: the only seal there is a 12 dollar o-ring. Take you about 3 hours to get to it provided you have access to a few jacks to pull the cradle and a trans jack to support the trans. If you were close to me in Dallas I could help you out.

 

Fluid is not red. I may need that O ring.

 

Factory service manual for diff removal shows to completely remove the torque tube along with transmission and diff after removing the rear cradle. I am assuming that your 3 hour job doesn’t so that deep. Any step by step procedures you can provide would be appreciated!

 

Ill try real quick, probably miss a step, but ive had mine in and out 3 times in the past 3 months.

Jack up car
drain diff
Unhook air intake from throttle body(the engine will tilt back as you drop the trans/diff down)
pull wheels
pull brake calipers(no need to pull brackets)(15mm socket and 16mm wrench)
remove brake line bracket from frame in wheel well(10mm)
unplug abs sensors
disconnect emergency brake cable from brake and remove from spindle(odd 3 tabbed thing, use 2 slot screw drivers)
remove upper control arms at frame(18mm)
remove upper shock mount from frame(13mm)
Remove 2 nuts holding diff mount to sub-frame(15mm I think, maybe 17mm)
Pull axle shafts from diff(I just grab the spindle and pull and it will pop free of the c-clip on the output shaft)
Support the trans/diff with a trans jack. I generally do this further forward on the trans so I have room to slide my motorcycle jack under the subframe.
Support the sub-frame with another jack of some kind(I use a motorcycle jack).
Undo the 4 sub-frame to main frame nuts(21mm I think it is). DO NOT USE IMPACT TOOLS ON THESE NUTS EVER
Start to lower the sub-frame taking care to unclip wiring and hard brake lines. Slide the sub-frame out of the way so you can work.
Remove the mufflers(13mm)
remove the H-pipe(13mm, 15mm, and dont remember what the h-pipe to exhaust manifold was, I think 17mm)
remove the tunnel brace(a ton of 8mm screws)
Drop the trans/diff down until you have clearance from the rear tub to slid the diff off the trans output shaft.
Remove the bolts and nuts(15mm and 13mm wrenches)
Support the diff with another jack(a regular floor jack works just fine) and proceed to slide the diff off the trans. This works better with 2 people, but ive done it alone. One person to manipulate the jack and the other under the car working the diff of the trans.

I probably missed a step or 3, but thats the gist of it.

I tried the first time to not drop the exhaust and tunnel plate... cant be done. The diff hits the tub and no way it will ever come out.

 

Thanks for that. It’s what I needed. Maybe I’ll catch any steps you missed as I move slowly forward.