DIY: manual transmission and diff fluid change

[parapraxis24]

Great DIY! I'm looking at buying a used 128i, and this will be on the list of maintenance to tackle fairly early on. Thanks!

[crowtrobot]

Did the transmission yesterday (DIY was great help thank you!). Ran a hose out to engine bay with a funnel and filled with Redline D4 ATF. The fill started overflowing after ~1.75qt or so. My understanding is that the reservoir is 2L so 2+qt, so I'm curious why this might be? Did I not let it drain enough? The car was on a slight decline (5deg max) - the front was on ramps while the back was on jackstands. Would this have trapped 0.25qt of old oil?

Also, the fill never really stopped seeping, I sealed it up when it slowed, but not stopped - the FCP euro DIY video shows them sealing it up right away, wouldn't this pressurize the gearbox?

I ran it a bit after buttoning everything back up, felt pretty good, though maybe slightly notchy, but hard to tell if it's placebo, new fluid, new fluid type, etc.

[Dackelone]

Originally Posted by crowtrobot

Did the transmission yesterday (DIY was great help thank you!). Ran a hose out to engine bay with a funnel and filled with Redline D4 ATF. The fill started overflowing after ~1.75qt or so. My understanding is that the reservoir is 2L so 2+qt, so I'm curious why this might be? Did I not let it drain enough? The car was on a slight decline (5deg max) - the front was on ramps while the back was on jackstands. Would this have trapped 0.25qt of old oil?

Also, the fill never really stopped seeping, I sealed it up when it slowed, but not stopped - the FCP euro DIY video shows them sealing it up right away, wouldn't this pressurize the gearbox?

I ran it a bit after buttoning everything back up, felt pretty good, though maybe slightly notchy, but hard to tell if it's placebo, new fluid, new fluid type, etc.

The manual trans hold just under 2 liters of fluid. I always remove the fill plug FIRST, then the drain plug at the bottom. Its no fun finding out your fill plug is stuck/seized, after draining out all your trans fluid.

I always let the drain plug out and wait until it stops dripping old fluid out. Then I fill the trans until fluid spills out the side/fill plug. It is important to make sure your car is LEVEL! Sounds like maybe your's wasn't. You can use a bubble carpenter's level placed on an open door sill to check how "level" your car is - next time around.

The gearbox has a breather on the top of it. So it's not pressurized.

Dack

[crowtrobot]

Originally Posted by Dackelone

The manual trans hold just under 2 liters of fluid. I always remove the fill plug FIRST, then the drain plug at the bottom. Its no fun finding out your fill plug is stuck/seized, after draining out all your trans fluid.

I always let the drain plug out and wait until it stops dripping old fluid out. Then I fill the trans until fluid spills out the side/fill plug. It is important to make sure your car is LEVEL! Sounds like maybe your's wasn't. You can use a bubble carpenter's level placed on an open door sill to check how "level" your car is - next time around.

The gearbox has a breather on the top of it. So it's not pressurized.

Dack

Very helpful, thank you Dack!

Definitely opened the fill first, like you said, don't want to end up with an empty gearbox and no way to fill Must have been the slight incline in the car. Will have a second set of jackstands this weekend, hopefully it'll warm up enough and I can get under there with a syringe and top it off with a more watchful eye.

Good to know about the breather as well. Again, very helpful, thanks for the tips.

[Dackelone]

Originally Posted by crowtrobot

Very helpful, thank you Dack!

Definitely opened the fill first, like you said, don't want to end up with an empty gearbox and no way to fill Must have been the slight incline in the car. Will have a second set of jackstands this weekend, hopefully it'll warm up enough and I can get under there with a syringe and top it off with a more watchful eye.

Good to know about the breather as well. Again, very helpful, thanks for the tips.

^^

I would just drive the car for a few more weeks... then change the fluid again. You really can't hurt anything by changing the fluid again.

Dack

[325d09]

Very interesting read and knowledgeable group! One question tho. Want to replace geaebox oil and diff but mine is a 325d 2009 pre lci manual thus is it same oils as whats on this thread oor different? From what i have read i am lead to believe 75w90 is way to go for both??
Many thanks in advance.

[Dackelone]

Originally Posted by 325d09

Very interesting read and knowledgeable group! One question tho. Want to replace geaebox oil and diff but mine is a 325d 2009 pre lci manual thus is it same oils as whats on this thread oor different? From what i have read i am lead to believe 75w90 is way to go for both??
Many thanks in advance.

You can use the same oils as mentioned in this thread.

I think for your car BMW originally spec'd MTF-LT3 oil for the manual gearbox fluid and 75w140 gear oil for the diff.

LT3 has now gone to LT5 specs from BMW. As for the diff you could use a 75w140 oil or a 75w90.

IF you can get ahold of Redline oil in the UK... I would go with either their MTL or MTL90 for the gear box(manual trans, GL4 rated) or even their ATF-D4(I still like this oil in my manual gearbox!). I think Redline also makes a MTF-LT5 compatible gearbox oil too.... but I forget the Redline name for it - at the moment. Maybe contact Redline to see what they recommend now.

For the diff... you can use a 75w90 or a 75w140 GL5 rated oil. I use the latter - since I drive a lot on the Autobahn at very high speeds(>285 kph)

Dackel

[jlc45]

The level for the oil/fluid in a manual trans is not that critical so long as it's close. This is filed under "hard to believe" but i'll recount the story anyway;
when I was working as a transmission mechanic in a former life (in the 80's) we had a Toyota come in making noise from the trans. We took it out and checked it. It was bone dry and had some metal residue in it but everything looked physically OK. We rinsed it out, filled it with fresh oil and reinstalled it. It was fine. Nothing wrong with it! Amazing. But I also owned a Mazda pickup and it went through two sets of bearings in 300,000 km. I am skeptical about the use of ATF in a standard trans. I think motorcycle motor oil might make more sense, since in a MC the same oil lubes the engine and the trans and usually the clutch as well. Comments? I am still deciding what to use in my 135i. The oil in it now is no good in cold temperatures.

[Dackelone]

Originally Posted by jlc45

The level for the oil/fluid in a manual trans is not that critical so long as it's close. This is filed under "hard to believe" but i'll recount the story anyway;
when I was working as a transmission mechanic in a former life (in the 80's) we had a Toyota come in making noise from the trans. We took it out and checked it. It was bone dry and had some metal residue in it but everything looked physically OK. We rinsed it out, filled it with fresh oil and reinstalled it. It was fine. Nothing wrong with it! Amazing. But I also owned a Mazda pickup and it went through two sets of bearings in 300,000 km. I am skeptical about the use of ATF in a standard trans. I think motorcycle motor oil might make more sense, since in a MC the same oil lubes the engine and the trans and usually the clutch as well. Comments? I am still deciding what to use in my 135i. The oil in it now is no good in cold temperatures.

I wasn't saying to use any ATF oil in your manual transmission... but to use Redline Oil's ATF-D4 as they have been recommending this fluid for BMW manual transmissions for years and years(like way back from my e36 days).

I just doubled checked Redline's website and they are still recommending:

for a N54, 135i they recommend:
ATF-D4 fluid for the 6 speed manual transmission and 75W85 GL-5 Gear Oil, for the differential.

for a N55 135i or iS or a 1M(since they have the SAME manual trans) they recommend:
ATF D6 fluid for the 6 speed manual transmission and 75W140 GL-5 Gear Oil for the differential.

www.redlineoil.com/application.aspx


Some BMW members will use Redline's MTL 75W80 GL-4 Gear Oil, in the manual transmission. I'm currently running MTL is both my 135i and my e39 540i. It works fine, but when its cold outside(bellow freezing) the trans does take a few miles before it shifts nicely. I think for the next winter I will be switching back to ATF D4.

https://www.redlineoil.com/product.aspx?pid=45&pcid=7

The level for the oil/fluid in a manual trans is not that critical so long as it's close.

Yep, agreed.

While it's not super critical to have the car level - when refilling the trans and diff fluids... I would certainly encourage a DIY to get the car fairly level. I used a water-level placed on an open door sill to check the angle of the car - up on jackstands.

When a transmission has the wrong amount of fluid in it... when its too low("under filled")... generally the the trans will start to over heat the higher gears. Normally this is 5th/6th gears bc they sit highest up inside the trans case.

When a transmission is over filled... the oil can froth up and puke out of the topside air breather on the trans. Not only does this cause a real mess... but you run the risk of blowing a trans case seal or output shaft seal.

Just get the car up in the air and level as you can... they when re-filling the trans or diff... keep pouring oil into the trans/diff until oil start spilling out. This is why its always better to have MORE fluid than not enough. Plus you have some fluid left over for your next trans/diff service.

Dackel

[Stubbie Blue]

Thanks for this DIY. I bought my 2012 135i used with 33k miles on it, and after about 1 hr of city driving it seemed like the fluid got too hot and thin that I had difficulty engaging 1st from a standstill. Also I usually heel and toe into 3rd every time I slow down, and it was very notchy.

The Red Line website says to use D4 ATF but I decided to try MTL which is a bit thicker due to my high temp issues in Florida.

The procedure was pretty much the same as the 128i. 8mm hex sockets for both the fill and drain plugs, and there were no washers. I used a 3/8" drive breaker bar with no adapters so did not need low profile hex sockets. I only needed about 1.5 qts of Red Line MTL, and drained about 1.25 qts of the original fluid.

I could immediately feel an improvement in the shifts. The notchiness was pretty much gone and all gears engage like butter now. Don't pay attention to BMW's 'lifetime fluid' recommendation. It's just $32 for 2 qts of Red Line MTL and the transmission feels amazing now.

[Gray_Panther]

Originally Posted by Stubbie Blue

Thanks for this DIY. I bought my 2012 135i used with 33k miles on it, and after about 1 hr of city driving it seemed like the fluid got too hot and thin that I had difficulty engaging 1st from a standstill. Also I usually heel and toe into 3rd every time I slow down, and it was very notchy.

The Red Line website says to use D4 ATF but I decided to try MTL which is a bit thicker due to my high temp issues in Florida.

The procedure was pretty much the same as the 128i. 8mm hex sockets for both the fill and drain plugs, and there were no washers. I used a 3/8" drive breaker bar with no adapters so did not need low profile hex sockets. I only needed about 1.5 qts of Red Line MTL, and drained about 1.25 qts of the original fluid.

I could immediately feel an improvement in the shifts. The notchiness was pretty much gone and all gears engage like butter now. Don't pay attention to BMW's 'lifetime fluid' recommendation. It's just $32 for 2 qts of Red Line MTL and the transmission feels amazing now.

I will have to try this again next weekend because I couldn't get the filler plug off with the small tool I was using. I will use the breaker bar method.

I don't feel comfortable getting the car on jackstands, because I don't have the right ones to hold the car in the air.

I will run a hose from the top of the engine into the transmission filler hole instead.

[Suprgnat]

Originally Posted by Gray_Panther

I will run a hose from the top of the engine into the transmission filler hole instead.

[Stubbie Blue]

Originally Posted by Gray_Panther

I will have to try this again next weekend because I couldn't get the filler plug off with the small tool I was using. I will use the breaker bar method.

I don't feel comfortable getting the car on jackstands, because I don't have the right ones to hold the car in the air.

I will run a hose from the top of the engine into the transmission filler hole instead.

Actually if you have a Harbor Freight near you, I get a lot of my tools from there really cheap with coupons.
-$14 hex socket set
-$10 E-Torx set (not needed for fluid change, but I see a lot on BMWs)
-$9 3/8" drive breaker bar
-$5 fluid transfer pump
-$80 3 ton low profile floor jack

I had the front on ramps, jacked up the rear by the cross member behind the diff, and put jackstands with ebay rubber adapters under the rear jacking points.

[Stubbie Blue]

My transmission was starting to feel notchy again after the fluid change. So I jacked it up again. There were no signs of leaks. Opened the fill plug and nothing overflowed out. So I pumped in more fluid and ended up putting around 0.4 qts, bringing the total to 1.9 qts. This time when I removed the fill tube, there was a small stream of overflow, but I just put the fill plug in as fast as I could. Went for a drive and it was shifting smoothly again.

I guess there are some nooks and crannies inside that don't get filled up until you drive, so be aware that you may have to recheck the level and top up.

[Dackelone]

Originally Posted by Gray_Panther

I will have to try this again next weekend because I couldn't get the filler plug off with the small tool I was using. I will use the breaker bar method.

I don't feel comfortable getting the car on jackstands, because I don't have the right ones to hold the car in the air.

I will run a hose from the top of the engine into the transmission filler hole instead.

The "plugs" are very tight from the factory. A breaker bar will be needed. But when you re-tighten the plugs/screws... you don't need to use so much force/torque.

Also... I know this sounds dumb... but double check to make sure you are turning your wrench/breaker bar the correct way to loosen the plugs. A lot of people get messed up when they work upside down under a car - trying to remove a fastener. Lefty, loosy, righty tighty!

Originally Posted by Stubbie Blue

My transmission was starting to feel notchy again after the fluid change. So I jacked it up again. There were no signs of leaks. Opened the fill plug and nothing overflowed out. So I pumped in more fluid and ended up putting around 0.4 qts, bringing the total to 1.9 qts. This time when I removed the fill tube, there was a small stream of overflow, but I just put the fill plug in as fast as I could. Went for a drive and it was shifting smoothly again.

I guess there are some nooks and crannies inside that don't get filled up until you drive, so be aware that you may have to recheck the level and top up.

It's always a good idea to re-check one's work.

Dackel

[Hops128i]

Originally Posted by Stubbie Blue

My transmission was starting to feel notchy again after the fluid change. So I jacked it up again. There were no signs of leaks. Opened the fill plug and nothing overflowed out. So I pumped in more fluid and ended up putting around 0.4 qts, bringing the total to 1.9 qts. This time when I removed the fill tube, there was a small stream of overflow, but I just put the fill plug in as fast as I could. Went for a drive and it was shifting smoothly again.

I guess there are some nooks and crannies inside that don't get filled up until you drive, so be aware that you may have to recheck the level and top up.

I've been on the fence whether to DIY or have someone else do it, but your post really makes a good case for DIY.

[Stubbie Blue]

Originally Posted by Dackelone

It's always a good idea to re-check one's work.

Dackel

Sure, I agree. Do you think it should be part of the procedure to close everything up and go for a drive to fill any nooks inside the tranny with fluid, then recheck the level and top it up?

[Dackelone]

Originally Posted by Stubbie Blue

Sure, I agree. Do you think it should be part of the procedure to close everything up and go for a drive to fill any nooks inside the tranny with fluid, then recheck the level and top it up?

That would not be a bad idea. Or even to just recheck the trans fluid after a week or two of driving around.

Dack

[ThatKidDavid]

Hi sorry if this has been asked before but I own a 2011 135i 6MT and I had a transmission replacement so it has ~20,000 miles and I want to replace the transmission and differential fluid. I live in southern California and the temperature rarely drops below 40° F but can go up to almost 100°F. I have come to the conclusion of getting Redline MTL for the transmission but I'm unsure of what to get for my differential, it's an eLSD open diff, any suggestions on the weight i should get? I'm looking for the smoothest, reliable shifts I can get for my environment

[Hops128i]

Finally got transmission fluid done, thanks to this great thread! While it's a simple job, there are a few things that made it more than an oil change level DIY. Just a few notes:
- I used OE MTF-LT-3 from the tall narrow 1 liter bottles. You really have to be careful not to tip these while under the car.
- I used a simple $8 gear oil pump from harbor freight, while it works fine. Space was tight and getting the pump into the bottle without spilling really took care. Earlier in this tread, someone posted that they filled with a decent length of tubing going from the top of the engine compartment with a funnel. I think this is the way to go. I would do it this way next time, instead of fumbling with tippy bottles in a cramped space under the car.
- It took a total of 1.7liters of fluid to reach the fill hole.
- I didn't see any measurements on the filler plug width for finding compatible tubing, so attached an image.

[Dackelone]

Originally Posted by ThatKidDavid

Hi sorry if this has been asked before but I own a 2011 135i 6MT and I had a transmission replacement so it has ~20,000 miles and I want to replace the transmission and differential fluid. I live in southern California and the temperature rarely drops below 40° F but can go up to almost 100°F. I have come to the conclusion of getting Redline MTL for the transmission but I'm unsure of what to get for my differential, it's an eLSD open diff, any suggestions on the weight i should get? I'm looking for the smoothest, reliable shifts I can get for my environment

Redline has an application guide now...
www.redlineoil.com/application.aspx

It says to use their ATF-D4 for your six speed manual trans and 75W90 GL-5 rated Gear Oil for the diff.

Lots of guys love MTL... so I think you could use that as well.

Dackel

[SSMoverRot]

Wow, really nice DIY write up with great pictures