Using redline MTL

Drew20

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think I've mentioned it before, I have (I think) a worn synchro on 2nd, so downshifts require a blip of the throttle to make it smooth, upshifts are fine. I was therefore planning a box rebuild this winter, but then thought MTL is a low cost option to (hopefully) defer the cost of a rebuild for a few years at least. So 50/50 MTL is the new plan A.
Questions:
Why not use 100% MTL? I've gone 100% MTL on a VW before and it was fine, but from looking on this site, everyone seems to go for 50/50.
Is there any best option for the other 50%? I'd thought to just reuse the current box oil, but then again, I can do better than that, as I've no idea what the current fill is.

Thanks team
:):)
 

m5bb

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MTL is recommended for pre 80's 5 speeds. Don't know why it can't be 100%. That's what all the E28 guys run.
The transmission engineer for Rahal Letterman racing told me at a track years ago to put about 8 ounces of STP oil treatment in my M5 280.
I did and it cut down on a little catch it had going into second.
 

stphers

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I just put 100% MTL into an older noisy ZF gearbox. It was OK shifting but noisy as hell. The shifting improved very slightly, mostly when it is little colder but a lot of the bearing noise got much less, did not make it all go away but now, at least, it is drive-able. Have to wait and see if there is any improvement on the oil leaks Oops, sorry, oil sweating . I don't think that the MTL will be able to fix that part but as I said, much quieter now.
 

Gary Knox

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I believe sfdon recommends the other 50 be a good grade GL-4 manual transmission oil. I found an 'oil testing' website a while back that rated the Amsoil GL-40 the best of about a dozen oils tested.

Just installed that 50/50 blend in my 265/6 OD transmission. It took essentially the full 2 quarts.

Won't be driving it for several months, so don't know how it functions with the new lubricant.
--------------------------------------------
PS: Had a decent day of weather, so went out for a 10-15 mile drive a few days after the transmission oil change. Transmission shifts very well - smoother than before, and I think it is quieter as well. Glad I made the change
 
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Drew20

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Thanks, that's a few options better than reusing whatever's in the box now. Will look for the amsoil GL4 here in the UK.

Ta
 

sfdon

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It’s Carl who suggests the mineral oil.
It works!
 

aearch

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WHATEVER REDLINE IS THE BEST OIL IN THE WORLD PERIOD
RIGHT AROUND THE BLOCK FROM ME
MY NATIVE TOWN
 

Drew20

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My job for tomorrow, more fun than xmas shopping I think

Going to need some plastic pipe as neither bottle has a squirty nozzle thing.

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And if it ever stops raining I hope to get a chance to try it out before they start putting salt down, otherwise no running report until spring
:(
 

Stevehose

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If you are doing this refill solo, I get a large funnel and about 5' of clear tubing and hang the funnel from the rafter with a coat hangar, then use a pair of long nose vice grips as a hemostat on the tube about a foot from the end. Then you can insert the tube into the tranny, undo the pliers, fill, and close the tube back off when full.
 

Gary Knox

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I've been filling automatic and manual transmissions as well as differentials for about a dozen years using a small pump designed for oil fluids, with a couple of pieces of clear plastic tubing. These are frequently used by people who maintain their own boats. Pump operates on 12 volts and I installed a push button switch in the positive feed wire to start/stop pumping operation. Takes about 3-4 minutes to pump a gallon of fluid into an auto transmission, half that to fill a manual or differential. I use a small 7-10 amp 12 volt battery, or connect to any other 12V source. SO MUCH easier, cleaner, and quicker than the hand pumps I'd used before. Pump cost about $25, and I've used it at least 20 times, so I considered it a good investment.

Gary--
 

Drew20

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Well, my set up's a bit more Heath Robinson, I've tucked a hose in behind the head, down past the exhaust into the fill plug. I'll let you know how I get on later. Been told I need to do xmas decorations before I get to play with the car
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bluecoupe30!

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If you are doing this refill solo, I get a large funnel and about 5' of clear tubing and hang the funnel from the rafter with a coat hangar, then use a pair of long nose vice grips as a hemostat on the tube about a foot from the end. Then you can insert the tube into the tranny, undo the pliers, fill, and close the tube back off when full.
This is the point when neighbours start jockeying for position outside the open garage door to see what happens next....:D
 

Willem Tell

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What about in the diff?
I will change the oil in both tranny and diff next Spring.
Does it make sense to do both 50/50?
 

Mal CSL 3.0

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Hi,

In my owners manual it says use SAE80 manual gearbox oil.

As many posters suggest MTL I am hoping using 100% will quieten my MT a bit.

MTL comes in 80W/90 and 75W/80. So which one is the ideal choice?

And is 2 quarts enough?

Thanks

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