• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Gearbox and differential oil change

Share this page

Wana

Wana

Jedi Hopeful
Offline
One of the last items on my winter maintenance and project list is to change the oil in my gearbox and differential. My question is, should I wait until I can take the car for a run and get the oil nice and warm, or will it all drain out well enough if I do it without getting it warm? I would think just leaving it sit with the drain plugs out for an hour or so would do the trick?
 
I would warm it up somehow. You see there's probably some sludge lying in the bottom of both cases. Sludge just won't come out in an hour or two. Possibly you could use a heat gun aimed at the bottom of the cases then let stand without plugs overnight.

When you drain the transmission don't forget to also drain the overdrive. Clean the screens up and replace.
 
You would be better off if you can drive it around to warm it up. You will get a better cleanout since more of the foreign particles in the trans and dif are in suspension in the fluid when you drain it.

Mark
 
Thanks guys. Looks like this job will wait for a while... we're having a blizzard here today.
 
If you are really worried I recommend warm-up drain -refill. Warm-up drain refill. The cost is double for the fluid but you get a better rinse. I do this on all new unknown gearboxes and motors. Perhaps I am a bit crazy but I do feel better about the cleanliness of the innards. Be sure to use a magnet on your drain plug to help keep the particles from moving across precious parts.
 
bigly, i like your idea for keeping it clean, the book recommends changing the oil when you have "just completed a run" meaning while its hot at 6000 mile intervals. refill with castrol gtx 6-1/4 pints. some folks have been using "red line" /bcforum/images/%%GRAEMLIN_URL%%/savewave.gif
 
I switched from Castrol GTX 20/50 to Redline MT90 in the trans. I get smoother 2nd gear shifts and better cold shifting. You can also increase the mileage between changes with Redline.

If I was going to do a double fluid change, I would start with the Castrol since it is cheaper to "throw away". Motor oil is also designed to keep particles suspended so you might get more out on the first change. Redline, being designed as a trans fluid, will tend to not keep particles suspended so as not to keep them moving through the gears. This is because most trans don't have oil filters as engines do. In transmissions, you want the particles to drop to the bottom of the case. In engines, you want particles stopped in the filter.

Mark
 
marka, i agree, good point im going to start my trans. rebuild today (i hope) when done ill also be using "red" line! /bcforum/images/%%GRAEMLIN_URL%%/iagree.gif
 

Attachments

  • 4560-MVC-016S.JPG
    4560-MVC-016S.JPG
    37.3 KB · Views: 168
Hi wanna, Do it hot otherwise the OVD accumulator will not drain properly.---Fwiw--Keoke
 
Back
Top