Frustrated by being unable to locate a 17mm hex lug anywhere in Williamsburg, I took my 928 to my local shop and asked him to drain and fill the differential for me, top off the transmission and drain/fill my coolant.

How hard could that be I thought (having not done any of it yet my self...)

Well, I picked the car up 4 hrs later and asked how'd it go? He told me he didn't have the correct tool to top off the transmission...needs to be added under pressure or something to that effect??? Drained and filled the other two tasks though.

After I got home, I looked at the job sheet and noticed he had written down "70 11 40 gear oil" -- What is that?

I left the manual open for him on the arm rest showing SAE 90 recommended for the differential -- what is 70 11 40 gear oil?

Do You suppose he meant to write 75W-140? If that is in fact what is now in my differential (I have the LSD) - is that going to be an issue for me here in VA? I think he used Amisol - I'll confirm tomorrow after he reopens.

Mike

 

17mm hex sockets can be found on Ebay for ~$15. I bought one early in my 928hood, to discover that S4+ diffs don't use the 17mm hex plug. Duh.....

Enterprising cheapskates might get an M10 (17mm head) and crank two nuts together on the threads, then use the head of the bolt as your hex driver.

Dunno what 75W-140 would do, I'll leave that to the tribologists. I'd guess it'll sap some horsepower and generate a lot of heat if you go racing....

Diff oil can be pumped uphill using a $3 pump attachment that screws (or at least sits) into the top of your quart jug of 75W90 gear oil. The attachment can be had at any NAPA/Pep Boys/Kragen, then you take it to Home Despot and fit a 3 foot length of plastic tubing of appropriate diameter:

 

Transaxle is $5000 to rebuild, not worth experimenting with oil Porsche did not spec. 140W is used in truck rears, I would think the LSD would chatter when making a turn.
Drain and refill with Redline 75-90w. You'll sleep better.

 

There is a rubber plug under the rear glove box, where you could feed the plastic line through and find its way to the top filler opening. then, you can hang a funnel near the hatch hinges and just pour and wait. With my race car, there is no glove box, so its real easy. If the rear glove box can be removed easily enough, it would be worth a try. sure beats using that pumps with 90 weight oil!!!

mk

 

Just buy a 1/2 gallon garden sprayer (less than $10) , pump up variety with a nozzle on a flexi hose. Remove spray nozzle and trigger just leaving hose. insert oil into container, insert pipe into fill hole in tranny, make sure it won't fall out, pump up sprayer and go have a cup of tea.

AND MAKE SURE WHEN YOU START THE JOB - THE FIRST PLUG TO REMOVE IS TH FILL PLUG NOT THE DRAIN PLUG.

 

You can also feed the line via the rubber grommet by positive battery cable.

 

Mike
The shift action of my 5-spd LSD was completely transformed by changing to Mobilube 1 gear oil. I strongly recommend you do the same.

As for filling it. Once you have the correct allen (hex) key all you need is a funnel and about 10ft of hose. Put the hose into the filler hole, it doesn't matter if the hose sags below the filler as long as you hang the funnel at a point higher than the filler. Pour in the Mobilube 1.

Colin. 89GT.

 

WAR MOBILE 1! Mine shifts like butter, baby. I did mine with the gravity method, and IIRC I got the 17mm @ Sears. GL!

 

Mechanic told me this morning he put 90/140 weight gear oil in the differential (I misread his handwriting).

I'm no oil expert - the manual calls for SAE90...I've put 150 miles since and can't detect any difference, loss of power, etc. He told me the original oil didn't look dirty...but I'm not sure how many miles were on it.

Cruising the internet I've read that BMW's M3 uses 75W-140 and Ferrari uses a 200+ wt oil!

Mike

 

For some reason , i couldnt use that hole. (i might have plugged it up when i changed my battery location. good idea though, would probably be worth just drilling out a big hole and pluggint it with a rubber grommet. ive done the pump enough to know, there has to be a better way! (although, its only about 5 min of pain!)

mk

 

Hi,
you should drain the oil which has been installed
That lubricant is incorrect - it should be done ASAP

The correct lubricant is a GL5 75w-90 (this replaces SAE90) a synthetic is best

Mobil 1 75w-90 will work very well but there are a number of others. you do not need to waste your money on a "boutique" gear oil

Regards