Transmission Experts Weigh In

[Overboost]

So I have decided to finally service my GM A5S390R (GM 5L40-E) transmission. I had a small leak from the selector shaft but now I can't help but wonder how much it has leaked before I noticed it. I am thinking it must be low so it is time to drop the pan, replace the filter and pump in some fresh ATF.

I want to do a filter and fluid change and then a simple drain and change the next day once cooled back off so my decision on preferred ATF will be depending on my budget.

What I am asking everyone is what is the preferred ATF for my GM transmission and also if this thread gets any traction, what is the preferred replacement ATF for the ZF boxes as well. (My E46 has the ZF 5HP19)

There is a list over on E46Fanatics from member Balidawg and I have copied it here for reference. Feel free to add any missing fluids or any suggestions you might have.

I would love to hear from others and especially RRPhil as he is the one man I know really knows his stuff on automatic transmissions.

GM - Dexron VI
AC Delco Dexron-VI: http://www.acdelco.com/auto-parts/ve...dexron-vi.html
Amsoil Signature Series Fuel-Efficient Synthetic: https://www.amsoil.com/shop/by-produ...mission-fluid/
Castrol Dexron-VI: https://www.castrol.com/en_au/austra...ax-dexron.html
Havoline Global Multi-Vehicle: https://cglapps.chevron.com/sdspds/P...&docFormat=PDF
Mobil Dexron-VI: https://mobiloil.com/en/automatic-tr.../dexron-vi-atf
Pennzoil Platinum LV Multi-Vehicle: http://www.pennzoil.com/en_us/produc...NhbGU9ZW5fdXM=
Redline D6: https://www.redlineoil.com/d6-atf
Super Tech Multi-Vehicle Low Visosity: https://www.walmart.com/ip/Super-Tec...1-gal/54310244
Valvoline Dexron-VI: https://www.valvoline.com/our-produc.../dexron-vi-atf
Valvoline Maxlife Multi-Vehicle: https://www.valvoline.com/our-produc...ti-vehicle-atf

ZF - LT71141
Castrol Transmax Import Multi-Vehicle:https://www.castrol.com/en_cr/ccsa/h...-multi-vehicle
Febi No. 14738: https://partsfinder.bilsteingroup.co...cle/febi/14738
Fuchs Titan 5005: https://www.fuchs.com/de/en/special/...itan-atf-5005/
Havoline Global Multi-Vehicle: https://cglapps.chevron.com/sdspds/P...&docFormat=PDF
Liqui Moly Top Tec 1200: https://products.liqui-moly.us/top-tec-atf-1200-1.html
Mobil ATF LT71141: https://www.mobil.com/English-GB/Pas...L-ATF-LT-71141
Pentosin ATF1: http://www.pentosin.net/specsheets/Pentosin_ATF1.pdf
Ravenol 5/4HP: https://www.ravenol.de/en/products/u...-hp-fluid.html
Redline D4: https://www.redlineoil.com/d4-atf
Royal Purple Max ATF: http://www.royalpurpleconsumer.com/p...mission-fluid/
Super Tech Multi-Vehicle Low Visosity: https://www.walmart.com/ip/Super-Tec...1-gal/54310244
Valvoline Import Multi-Vehicle: https://www.valvoline.com/our-produc...smission-fluid
Valvoline Maxlife Multi-Vehicle: https://www.valvoline.com/our-produc...ti-vehicle-atf
ZF Lifeguard5: https://aftermarket.zf.com/us/en/aft...l-change-kits/

[andrewwynn]

I've heard better to drain swap filter and put original fluid back in and top off so there isn't too much shock to the parts that are used to the amount of wear.

How many miles ?

[Overboost]

Originally Posted by andrewwynn

I've heard better to drain swap filter and put original fluid back in and top off so there isn't too much shock to the parts that are used to the amount of wear.

How many miles ?

180,000 pampered miles.

[andrewwynn]

Similar to mine. I'm a little closer to 190 actually but the first 128 were much more pampered than the 50,000 I put on I'm a bit of a lead foot.

[Clavurion]

If the box is still working normally with those miles I would be considering dropping the gearbox and renewing/refurbishing the torque converter. TC is the known weak link in this gearbox and when the locking clutch surface wears off metal debris will very soon destroy the rest of the box.

If you are going to change the oil why not flush change the whole content. You can do this by disconnecting the line going to oil heat exchanger. Guiding the fluid from there to a a drain reservoir and filling the oilpan with drill pump or similar while engine running. Dexron III -H is the specs. I've used Petro Canada ATF D3M.

Here are some pictures from 2007 when I did this first time to my E39 530d with the same gearbox. It had a new TC at about 300t km (preventative) and now running 400t km without a problem.

https://photos.google.com/album/AF1Q...5o-PwXajFVf-pc

[Overboost]

In all my research, I have found most transmission services were done after 100,000 miles. Yes, there may be a small percentage that did it religiously at 60,000 miles but I can only guess less than 1 or 2 percent of the owners followed that service interval.

I guess maybe the best route is maybe doing the filter and fluid change as this is still leaving 40% of the original fluid and see if it causes any problems for a week or 2. One look in the pan magnets should give some kind of indication that there was a problem that would have been inevitable.

I have avoided the transmission fluid changes exactly because of the issues you pointed out but I feel the pampered mileage along with zero transmission issues allows me the confidence this will only be a benefit.

Hopefully RRPhil posts some of his knowledge for all of us.

[andrewwynn]

I had thought that the super high mileage srmmm did the filter swap but it wasn't him. He's at like 360,000 miles on original filter and fluid!!!

[Overboost]

Originally Posted by andrewwynn

I had thought that the super high mileage srmmm did the filter swap but it wasn't him. He's at like 360,000 miles on original filter and fluid!!!

Yeah, Steve is a really nice guy. He actually came out and watched us race at COTA last year and I saw his X close up. That kind of mileage on his nice X5 gives me hope I can make it to 300,000 miles in my X5

[Overboost]

Originally Posted by Clavurion

If the box is still working normally with those miles I would be considering dropping the gearbox and renewing/refurbishing the torque converter. TC is the known weak link in this gearbox and when the locking clutch surface wears off metal debris will very soon destroy the rest of the box.

If you are going to change the oil why not flush change the whole content. You can do this by disconnecting the line going to oil heat exchanger. Guiding the fluid from there to a a drain reservoir and filling the oilpan with drill pump or similar while engine running. Dexron III -H is the specs. I've used Petro Canada ATF D3M.

Here are some pictures from 2007 when I did this first time to my E39 530d with the same gearbox. It had a new TC at about 300t km (preventative) and now running 400t km without a problem.

https://photos.google.com/album/AF1Q...5o-PwXajFVf-pc

Thanks Clavurion, but that might be a little difficult for me to replace the TC in my garage on my back and certainly no money to have it done. I will just pray to the BMW Gods to have mercy on me and not destroy my transmission because of a clutch surface.

I have seen the Dexron III-H, I think AC Delco offers one. I wonder if I should stay with the non synthetic or move to the synthetic Dexron VI

[Clavurion]

Originally Posted by Overboost

Thanks Clavurion, but that might be a little difficult for me to replace the TC in my garage on my back and certainly no money to have it done. I will just pray to the BMW Gods to have mercy on me and not destroy my transmission because of a clutch surface.

I have seen the Dexron III-H, I think AC Delco offers one. I wonder if I should stay with the non synthetic or move to the synthetic Dexron VI

I would still do the oil change by flushing the whole content especially if you are going to Dexron VI which is also compatible and has better wear abilities. This can be done if you have the vehicle on stands. Personally I think these myths about dangerous oil changes are mainly based on cases where someone has tried to rectify an already faulty gearbox with an oil change or the oil change was done wrong and there was too little oil in the sump (not filled while engine running).