R8 6spd trany and LSD fluid question

[stage247]

Hi. I`m driving 08 R8 6spd. I drove around 18000mile. I want to change LSD and transmission fluid. Anybody know how much I need put in? and what`s the proper viscocity of them?

[willyjp]

From the Audi Service Training Manual for the R8 (99B703):

Transmissions
The manual and R-tronic units are fully synchronized 6- speed transmissions, are internally identical, and have a torque output of up to 443 Lb-ft (600 Nm).
The gear oil of the transmission requires no regular maintenance. Either transmission can be removed and installed without removing the engine.

The Bentley R8 Service Manual notes that there is NO WAY to check the transmission fluid level (drain plug method not reliable) except to drain it and replace it
(4.0 l initial fill, 3.5 l recoverable); it states the transmission is "filled for life" and, in the maintenance schedules there is NO mention of routine checking or filling
of the transmission. The only mention of the transmission in routine maintenance is to "check for leaks." It also cautions to use ONLY the fluid available from Audi as
a "replacement part" and refers to the "electronic parts manual", which I do not have.

The owners manual, which you undoubtedly already looked into, make NO mention of transmission fluids (except the 4.0 l capacity), checking or filling or fluid spec, despite
a lengthy discussion of engine oil spec..

If I were you I'd leave the tranny alone. Not sure what you mean by "LSD."

PS: the 0.5 l of transmission oil not recovered on draining the transmission via the drain plug is in the transmission cooler.

[harrison]

LSD-Limited slip differential ?? Does the engine need to be pulled to change the clutch? Or maybe just the tranny?

[willyjp]

LSD-Limited slip differential ?? Does the engine need to be pulled to change the clutch? Or maybe just the tranny?

The (rear) "LSD" is integral with the transmission in the same case (a "trans-axle) and one assume it has the same oil supply. Probably why they're so fussy about what fluid you use in the tranny, since limited slips have special needs lubrication wise.

The front differential is not stated to be "limited slip" in any Audi literature I can find. It appears to be a normal differential. The Bentley R8 Service manual describes checking fluid level by the usual method of making sure it's full up to the drain plug, and mentions the reference to the Audi Parts manual for the proper fluid (no spec given).

The Audi maintenance schedule make no mention of any transmission or differential fluid change within the 120k mile service schedule.

Yes, Harrison, I'm pretty sure you can pull the clutch by removing the tranny and without removing the engine. In reading up on that, one interesting point I noted is that Audi sells pressure plates and clutch discs only together in matched sets, since apparently there are some matching requirements. So, in effect, you have to do the "whole" clutch if you do a disc (though they don't mention the T. O. bearing, I guess if I was going in to do the disc/pressure plate, I'd do the T.O. bearing too.

[harrison]

Last nite I switched off the ESP in a slick parking lot and the rear tires squeeled just like my Jeeps' rear end, on which I welded the gears..making it fully locked.

[willyjp]

Last nite I switched off the ESP in a slick parking lot and the rear tires squeeled just like my Jeeps' rear end, on which I welded the gears..making it fully locked.

no question the rear is limited slip...but I can't find anything that says the front is, or that really says anything about the front differential other than it being "a diiferential"

not sure I can quite get my head around how the viscous coupling would work in this situation, but I wonder if it wouldn't, in effect work backwards to stop a front wheel from spinning? what I mean is:

the way a viscous coupling (v/c) works is to become more "locked up", the more it senses a speed difference between the two sides

so the usual way it works is: the REAR is tending to spin so it's end in the v/c is turning faster, which starts to lock the coupling so torque is transferred thru the coupling to the front

but if the torque going to the front is causing a FRONT wheel to spin, that also will be prevented...front parts can't move faster than the back part without the v/c locking up and keeping both sides moving the same speed?

so maybe the front doesn't have to be limited slip?

not sure if that makes sense or not??