Project Royal Purple for tranny and diff - Need your help (junk yard experts welcome)

[JCtx]

Hey gang, finally got to it, and have car in the air, perfectly leveled (yes, I leveled it and marked it before lifting it, so I knew exactly where it needed to be ), but I'd REALLY like to activate the tranny cooler pump. I know it's not really necessary with less than 6K miles on the oil (it was clear), but since I'm putting a different fluid, would like to get as much out as possible. And also to make sure level is perfect by activating pump and checking level again. That's what the manual says, but manual also says to activate pump to empty cooler, which I think it's not entirely possible, as it doesn't pump air, right? However, I noticed tranny being lower than cooler, so maybe everything flows out without the pump, but you'd need the pump to fill??? By the way, lifted car really high after tranny finished draining, and nothing else came out, so I suspect cooler drained with the car flat, but fluid was hot. Cool fluid might not get there without the pump's help. Hmmm, which of all the possibilities do you think is true for the drain and the fill ?
Here are the options to activate the pump, so you can comment (and please also comment if you really think it's unnecessary):

1- Buy a connector from a junk yard (my preferred choice). My guess is most places just cut the wire, and leave the connector in the pump, since it looks like it's not detachable until close inspection (and you need a jeweler's screwdriver to detach). I'll attach a pic of the connector later on. Hopefully a junk yard 'junkie' can help me here , as there're no M3 V8s in this town. That way I just peel the wires off and apply 12V.

2- Buy a connector from a specialty place, but would need to have the precise info, which I don't have. I'd also need the correct terminals to insert in the connector. If somebody has knowledge on this, please shoot.

3- Locate the pins of the pump on the ECU and apply 12V there. This sounds too risky, as pins are extremely close together, and getting the wrong one could fry something expensive, so if they're not in a safer place, this option is discarded.

4 - Last option is to buy a relatively inexpensive code reader that has the option to activate the pump, which I doubt exist. Again, people with knowledge on this please comment.

Have the differential ready, and tranny ready to be filled up, but want to hear opinions first.

TOOLS NEEDED: A 14mm hex socket for the differential drain/fill plugs, an 8mm one for the tranny drain/fill plug, and a 22mm regular socket for the tranny filter. All 4 drain/fill plugs have a rubber seal (great), and the filter a regular crush washer I just sanded smooth to perfection. And I leveled the car with 2 Rhino ramps on the rear and jack stands in the front. You also need one low-profile jack and a pair of 2x6s to drive the car in front (no jack can get to the middle lift puck otherwise). Oh, and a pump; there's no way in hell you can get the fluid in there by yourself any other way.

As soon as I'm done will post my impressions on both fluids. I know several people wanted to do this, but they're a bunch of chickens . Good day gang.

[BMRLVR]

BMW dealers (good independant shops) have spare connectors on hand as well as the proper terminals and crimpers to make them. You could go to a dealer/indie and ask a tech to make you up a proper pigtail connector so you have it in the event you need to do the job again.

I agree with you on wanting to cycle the pump and get as much of the old oil out as possible!

[JCtx]

Originally Posted by BMRLVR

I agree with you on wanting to cycle the pump and get as much of the old oil out as possible!

Thanks buddy. After thinking about it, how can you supposedly empty the cooler via the pump if there's no fluid in the tranny? A fluid pump can't pressurize a line with air, can it? Besides, I lifted the car really high, and nothing else came out, so I'm pretty sure everything drained out.

My concern now shifted to make sure oil cooler is full , and THAT might need the pump to be run. On the other hand, the volume of fluid in the line and cooler seems to be really small, so maybe forcing a bit more fluid in the tranny and plugging it before it runs all out might be the answer. Just checked, and cooler is higher than the tranny drain plug, and about the same height than the fill plug, so most likely it drained, but won't fill (especially with thicker cold fluid). Maybe what I'll do for now is fill it up right before it drips, and now lower car all the way to the ground (have front wheels off), and leave it there for a while so cooler fills by gravity, then lift it level again and top the tranny off. But yes, will call the only reputable BMW shop in town and ask what you suggested. Thanks again.

[JCtx]

Hey gang, just occurred to me the cooler pump runs only when fluid reaches a certain temperature, correct? Can just shorting the 2 leads (grounding them) of the temperature sensor connector activate the pump????? That'd be super easy to do . I could try with the ignition on and see what hapens. The temperature sensor should be the only one at fluid level; all others are higher up. Comments welcome.

If I can't activate it, will do the lowering of the front, then fill it, then re-check it again after driving 20 miles or so. If level is correct, then next time won't have to do that.

[pbonsalb]

There are some anecdotal reports of diff failures with Royal Purple. There is also a comparison test of a number of diff fluids and RP did not do so well. There may be better choices, but do your own research. I have RP in one of my diffs and while I have not had any issues, I have a couple of quarts of Amsoil that will replace it. Usually I run Redline 75W90 or 75W140 depending on the specification for the car.

I have not read anything bad about RP in the tranny. Have not run it myself. I usually run Redline MTL depending on the specification for the car.

[BMRLVR]

Originally Posted by elp_jc

Hey gang, just occurred to me the cooler pump runs only when fluid reaches a certain temperature, correct? Can just shorting the 2 leads (grounding them) of the temperature sensor connector activate the pump????? That'd be super easy to do . I could try with the ignition on and see what hapens. The temperature sensor should be the only one at fluid level; all others are higher up. Comments welcome.

If I can't activate it, will do the lowering of the front, then fill it, then re-check it again after driving 20 miles or so. If level is correct, then next time won't have to do that.

Shorting the wires will not work since the computer will see zero voltage difference between signal and return voltage of the thermistor circuit (temperature sensor circuit) and set a low voltage code. The only way to fool the computer would be to use a resistor of the same value as the thermistor has when the fan comes on. It will be easier for you to try and power up the pump directly than turn on the pump with the thermistor.

If you have access to compressed air maybe you could pressurize the cooler lines with about 3-5 psi (use a regulator) and blow the oil out? Think that is a good option for you?

[JCtx]

Originally Posted by BMRLVR

Shorting the wires will not work since the computer will see zero voltage difference between signal and return voltage of the thermistor circuit

Thanks man; that makes sense, so won't even try it. Thought for a second it was directly wired, like old times .

I'm pretty sure everything drained out, so won't do anything in that regard. Now the issue is to have the tranny properly filled. Looks like I'll have no choice but to put the car on the ground, drive it for 20 miles or so, and lift it leveled again. What a PITA, but will report if I had to put more fluid, and how much.

Pbonsalb, as long as RP stops the chattering (pretty mild, to be honest), I'll consider the change a success. I'm not remotely worried about any fluid not holding up 10K miles at the most, let alone a fully synthetic one like RP. I do have personal experience with Redline MTL, and it stopped being effective by 10K miles. By the way, the M3 needs 75/140 in the differential, and Synchromax RP or D4ATF Redline in the tranny.

[kitw]

^ yeah, I like Redline MTL but it is not a long lasting fluid for some reason. I used to change it every 7500 (every other oil change) in my e36.

Just curious, did you try the factory friction additive for the diff?

[JCtx]

Originally Posted by kitw

Just curious, did you try the factory friction additive for the diff?

No man. Dealer wouldn't do it unless it's chattering like a MoFo (which is not), plus I didn't want them to touch my car anyway . And I wasn't going to pay $150 for 1-1/2 liters. Hopefully this will do the job.

I'm sure cooler drained, and is filling up as well because tranny ate the 2 quarts, and will have to go buy another. Oh well.

[JCtx]

Man, what a mess to fill both the tranny and diff, but I'm done. And won't make a mess next time as I know exactly how to do it now . Anyway, tranny took 2-1/3 quarts (calls for 1.8-qts), so I'm pretty sure it's completely filled. Differential calls for 1.3-qts, and took a little less than 1-1/2. Both drained hot and overnight, until absolutely nothing came out. Plus I inserted polypropylene shop towels to suck up the rest.

Will do another full brake and clutch bleed job now that tranny is exposed, front wheels off, and car lifted. It's a little less than a year since the last, but the hard part is already done, so might as well do it now . Will keep you posted on results, but the tranny looks promising, as RP fluid is visibly thinner when cold. But man, that Synchromax freaking STINKS!!! It's usually the differential fluid the offending one. Have a good one folks.

[Kenyon]

Originally Posted by elp_jc

Man, what a mess to fill both the tranny and diff, but I'm done. And won't make a mess next time as I know exactly how to do it now . Anyway, tranny took 2-1/3 quarts (calls for 1.8-qts), so I'm pretty sure it's completely filled. Differential calls for 1.3-qts, and took a little less than 1-1/2. Both drained hot and overnight, until absolutely nothing came out. Plus I inserted polypropylene shop towels to suck up the rest.

Will do another full brake and clutch bleed job now that tranny is exposed, front wheels off, and car lifted. It's a little less than a year since the last, but the hard part is already done, so might as well do it now . Will keep you posted on results, but the tranny looks promising, as RP fluid is visibly thinner when cold. But man, that Synchromax freaking STINKS!!! It's usually the differential fluid the offending one. Have a good one folks.

This is a technicians best friend when doing tranny and diff fill jobs. I think its still worth it for DIYers. It just makes everything easier and cleaner.

[JCtx]

Originally Posted by Kenyon

This is a technicians best friend when doing tranny and diff fill jobs.

Good idea man, but it's too big without a lift. I used a pump I had that screws to the bottle. Of course it was the wrong size, but used a graduated container to know how much I was putting in and pumped it from there. That thing pumps a lot; a dozen pumps or so takes care of a quart. For once every 2 years, it's okay. I initially tried squeezing the bottle thru a hose, but hose detached and made a mess . Then I remember about that pump. Thanks for the heads up anyway man; appreciate it.

[JCtx]

After getting air in the clutch and working on the other car, finally got the car done yesterday, and just came back from a spin. VERY pleased with the results. Notchiness is 80% gone, which that alone made the switch worth it. But add to that other shifts went from like-butter after 5 miles, to like-hot-butter after one. Oh, and no more chatter from the differential, so mission accomplished. Should have done it sooner now that I had to be the 'guinea pig' anyway . Wasn't as cheap as I wanted at $100 (2 Max Gear 75/140s and 3 Synchromaxes), but it's the best quality you can buy, and at a fraction of OEM, meaning I'm not contributing 50% for BMW coffers .

Having said the above, I'm the first to always say there's no free lunch on anything (like those who think a racing filter filters better than stock ), and that includes tranny oil. My guess is the much thicker BMW stuff would last longer, but I'll change it every 2 years, which means less than 10K miles in my case, so I MUCH prefer this oil than stock. I feel the same way about tires, since I don't track the car, but can't get anything other than max summer performance tires in stock sizes ; I prefer a better compromise between longer life, noise, and some winter capabilities vs all out grip I'll never use. Oh well.

Anyway, hope this helps those who were contemplating the switch to RP. Have a good one.

[Eurotrash8]

What is the scheduled change for the diff and tranny oil anyways? I couldnt find any info on the time or mileage...or maybe I'm not looking hard enough.

What other options for diff oil are there that is top tier and conform to our specs?

Did you end up filling both fluids up, drive around then refill or did the initial fill work fine?

[JCtx]

Originally Posted by Eurotrash8

What is the scheduled change for the diff and tranny oil anyways? Did you end up filling both fluids up, drive around then refill or did the initial fill work fine?

Manual calls for tranny and diff oil changes every other (computer-called) oil change, or around 30K miles. Diff oil needed is synthetic 75W140 with friction modifier. And am sure BMW only calls for their own fluid since they pay for service, but there's nothing unusual about our mechanical LSD. Plus in my case, those fluids will see less than 10K miles in 2 years, so I'm not remotely worried about using non-BMW fluids. In fact, I believe these are better than stock, and the tranny feels SO MUCH better that wish I had done this before.

No need to recheck differential, but you have to fill it with the car level. I marked a level with the car on the floor, and adjusted the level with the front jack stands (ramps on rear) to exactly the same mark. It's also important to drain fluids hot, after using car for a while. The tranny took 2-1/3 quarts, rather than the 1.75 quarts called for. I'm sure it won't need any top-off, but will recheck the level later on. Shifts fantastic now; couldn't be happier with the results, even though I still have some stock fluid in there. Will probably do another fluid change in a year, to get all the stock crap out of there .

Finally, due to possible bearing issues, I'll keep using the honey 10/60 oil, but I have zero doubt in my mind BMW is masking problems with that oil, as even Ferraris and Lambos use 5/40, which starts lubricating MUCH quicker on cold starts (especially in cold climates). Oh well. Have a great day folks.

[JCtx]

Originally Posted by Eurotrash8

Did you end up filling both fluids up, drive around then refill or did the initial fill work fine?

As I said before, no need to recheck the diff since there's no cooler. But just rechecked the tranny to be safe (after an 800-mile trip, to make sure fluid circulated for a while), and it was perfect (a little fluid coming out of the hole), so for those changing their own transmission fluid, no need to recheck level after filling it up . Just wanted to let the gang know.

Oh, and fluid tinted my shop towel purple, so whatever amount of stock fluid was inside, it was relatively little. Next time all stock fluid should be basically gone. Have a good one.