TT.Mk1 Transmission/Bevel Box Oil Replacement
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Back to 2000-2005 (Mk1)
Submitted and Entered by: MCPaudiTT
I replaced my transmission fluid with Redline MT-90 Synthetic Transmission Oil. This mod is supposed to improve the shifting feel. It did improve mine, though I was hoping for more... Best tip is to find and drain the Bevel Box. Most write-ups don't mention this. When you do it, you need to clean the magnetic plug as well - mine was full of filings... Signs of ground gears?
Other than the oil, there are no other filters, bolts, etc. needed.
You WILL need something to undo the plugs. It should be a 14 mm Allen Wrench (that is for my 2001, I hear later years may use different bits), that are hard to find (AutoZone has a set of 14/17/19 mm wrenches). If you can't find the bits, you can use a 3/8" bolt and two nuts. The head of the bolt is 1/2", or 12.7 mm, which is undersized for the 14 mm socket, but it worked...
Transmission Drain Plug Loosened
Using the double-nutted 3/8" bolt, I loosened the drain plug from the transmission. This is, of course, after I had a "helper" (thanks Nick!) remove the belly pan. I also changed my engine oil (my first time) with the pan off - no reason not to take advantage of it!
A helpful suggestion I have received is to remove the Fill plug first, just to make sure you will be able to refill the transmission prior to draining it. That sounds like a good idea, just in case!
Drain Plug Close-up
Smelly fluid drain
Make sure you have a bucket handy, as the fluid comes out FAST. After about 10 seconds, it is down to a slow drip. Also, the fluid is SMELLY!!! But so is the new stuff, so I guess that's OK.
Old Fluid
Here is my old fluid. It was quite dirty.
Bevel box drain plug
Most posts I have seen don't mention draining the Bevel Box. Those that do don't do anything BUT mention it. The Bevel box is what takes transmission power, and sends it back to the Haldex. It is located to the passengers side of the transmission, and sits further back. It is physically mounted to the Transmission. They SHARE fluid, so you need to drain it as well. The drain plug takes a 10 mm Allen key. Once out, mine drained about a cup of fluid (after the Transmission was empty)
Bevel box #2
You can see the engine oil pan drain plug at the top of this shot as well.
Bevel plug close-up
Bevel box magnetic plug
The Bevel Box drain plug has a magnet in the core, and collects filings from the system. Here you can see a bunch of chips/filings in the plug. These need to be cleaned out so that more (unfortunately) can be collected.
Magnet cleaning
You can remove ALOT of filings with a STRONGER magnet. It pulls them out of the plug. The magnet I used (MarTT's) has a flush face, so it was easy to clean off. The magnet is just a strong "dropped parts pick-up" magnet bought at Pep Boys - nothing special. It is VERY strong, though.
Magnet cleaning 2
Magnet cleaned
After pulling out debris with another magnet, I wiped the inside of the plug to clean out the oil, and as much other residue as I could. Here it is, ready to go back in.
Fill hole
This step really should be done first - Make SURE you CAN remove your fill plug before you drain. Seems obvious, but I didn't think about it. Fortunately mine did come out, so it was a non-issue. Here you can see the double-nut system in action. You need to work on the second nut to loosen, the first nut to tighten. Otherwise they work themselves free, and do you no good! In other words, this shot shows me LOOSENING the fill hole plug. If I were to tighten, I would have the wrench on the OTHER nut.
Filling tool
Here is the refill tool. You pull back the piston, fill it with fluid, cap it, and push the new fluid in to the system.
Charged and ready to fill
Here the system is ready and loaded.
Poised to fill
With the hose in the fill hole, just push on the plunger and fill the Transmission [Note: This photo acutally shows the lower drain plug not in. This is not correct. Obviously you need both the Transmission AND Bevel Box drain plugs installed PRIOR to adding fluid, or it will just come right back out]. Mine took over 3 quarts, but I spilled some. I would order 4 quarts to make sure I had enough. Just keep refilling the tube and pushing more fluid until it comes back out the fill hole (the same hole you have the tube in). Go slowly after 2.5 quarts so you don't make too much of a mess!
Once full, put the fill plug back in.
All three plugs have a 30 Nm (22 ft-lb) torque spec.
Put the belly pan back on and you are ready to hit the road.
Again, I do feel my shifts are smoother with the new fluid. It was not a cure-all, but it is a worthy addition.
FWIW, I believe that neither changing the fluid nor cleaning the magnetic plug are either listed as ordinary maintenance. I did the change solely because it was reported to make shifts smoother, and I was not happy with my 2-3 shift feel. I would do it again, and plan to change it every 20k or so now.
Back to 2000-2005 (Mk1)
