Transmission Fluid

[Coloradocurt]

Is there any "generally favored" transmission fluid for the 915 5-speed (non-racing applications)?

[OldSpool87]

Many threads on this topic all of which end in 80w90 Kendall or Swepco 201. Those are the most popular and generally accepted as fine choices.

[DRACO A5OG]

...and depends if you have Standard or Limited Slip Diff. Check the serial number of the bottom of your gear box.

[Coloradocurt]

Originally Posted by DRACO A5OG

...and depends if you have Standard or Limited Slip Diff. Check the serial number of the bottom of your gear box.

Thanks. My guess is that it's a Standard as it's a very nice, original 1973.5 911T (I'm getting next week). But other than the model number on the bottom of the tranny, what would be the give-away to answer the Standard vs LSD question. Or is the model number in-and-of-itself indicative of the answer to that?

[TimT]

With the car on a lift, or both rear wheels jacked up rotate one of the wheels,

Observe what the wheel on the other side does... if it rotates in the same direction, you have a limited slip...

If the opposite wheel rotates in the opposite direction you have an open diff..


I'd wager your car has an open diff..

[uwanna]

Originally Posted by DRACO A5OG

...and depends if you have Standard or Limited Slip Diff. Check the serial number of the bottom of your gear box.

If the model/serial number on the trans has a 12 between the model
and serial number it has LSD. EX: 915/73 12 12345
No 12 no LSD unless it was added later.

[Matt Monson]

Originally Posted by TimT

I'd wager your car has an open diff..

Most of them are, and I can't say that I've ever seen a T spec'd with an LSD.

Agree with the above about oils. People here argue about Kendall versus Swepco like their lives depend on it, but it doesn't matter. Either works.

['76 911S 3.0]

I have had good success with Kendall, hell so good it let me go from 3rd to 2nd at close to 80 mph with ease!

[Bill Douglas]

Handy helpful hint time. Before you drain the old oil out of the gearbox, make sure you can undo the filler hole on the side. Looking forward to seeing pic's of the new car

[72911]

I have used both Kendall and Swepco on two different boxes. One 7:31 and one 8:31 that I use for Grant Touring. Both boxes are original unrebuilt units and they both shifted EXACTLY the same. Both need lots of TLC when shifting and lots of double clutching (even triple when cold). I seem to have more leaks on the 8:31 Kendall box. I have had both boxes apart to inspect and just re-assembled with new gaskets since they both seemed to be in fair shape. My 2 cents.

[Johner]

I just did this for the first time this weekend. Very easy, just a bit messy. I used Kendall and there has been a nice improvement in shifting. I was also unsure about whether I had an Lsd, but as I had to jack the car anyway I just checked by turning one wheel and watching the other. Best tips were to undo the fill plug first and heat the oil in hot water before filling. With the cheap pump from Pelican it only took about one minute to pump each quart

[Sabai]

I use Swepco in my 915's and Motul in my G50's.

[Marc Bixen]

We love Kendall at Red Line. As for LSD or not, always go by the manual test, turn the wheels. We've worked on LSD cars with no LSD in them.And we've installed LSD's in many, DON'T GO BY THE TRANS NUMBER, parts can be changed. LSD additive will not hurt anything.

[911obgyn]

In my very high mileage 915 Kendall helped the syncros align in 1st and 2nd, easier shifts, and better cold morning driving. used both, Kendall is a bit cheaper too.

[G450X]

Originally Posted by 911obgyn

In my very high mileage 915 Kendall helped the syncros align in 1st and 2nd, easier shifts, and better cold morning driving. used both, Kendall is a bit cheaper too.

Same for me in my kinda high mile SC.