shifting issue/wrong atf?

I've been trying to figure this issue out for a while now with no luck. About two weeks ago I was going down the freeway and hit a metal shard and sliced my drivers side front tire and transmission oil pan. So lost all the fluid and had to be towed home. Replaced pan and refilled with dextron 3 like the big green sticker says. Now driving down the road it doesn't slip in any gear. The issue is during the gear shifts it revs up 500 to 1000 then drops and accerates normal. Fluid level is good. Does this warm and cold. I refilled the transmission correctly. Slim not sure if maybe the newer fluid is to blame or something else was hit that would cause this. My car is a 95 525i automatic. Has 220k on motor and body. Transmission has 110k

This is quite common. Your tranny is old, and the clutches are worn. Old fluid has become thick with wear and tear and thus compensates for worn clutches. New fluid is too thin, and worn clutches tend to slip during shifting.

The alternate explanation would be that the internal parts of the transmission, the oil passages and oil pumping mechanisms, have become too large from pumping around thicker fluid, to accommodate new thinner fluid. This is a form of damage.

The mechanical reason for this is still out there, but basically, the problem manifests when you change to new fluid, on an old transmission.

The solution is to replace your oil with thicker but new tranny oil. Either royal purple or valvoline has got a product called high mileage transmission oil. Use that. And after that, please do report your results back here.

I'm sorry, I know that this is going to be an expensive experiment, but someone here had the same problem, did the above, and fixed it that way. Please give that a shot. Your alternative would be to get a used tranny or rebuild your existing one, both of which are expensive affairs. [Since you've got a near classic car, you might want to consider a rebuild if you intend to keep her for the long term. ]

For good measure, before you change the oil, do the following :

1. Clean out your throttle position sensor. Use contact cleaner on the sensor and its socket, use a toothbrush to clean the contacts, apply dieletric grease and fix it back.

2. Delete all your error codes. Unclamp both your main and transmission ecu. Wait a few minutes, then reclamp them back. Start the car and let it idle with no throttle feathering, for around 10 minutes. Then go for a drive.

3. If the above two methods executed in sequence fail, then you've gotta try the high mileage tranny oil. You can keep your existing oil filter (assuming you changed it together with the new dex3 oil you just put in). Transmission oils are compatible with each other, so don't worry about flushing etc.


Please keep us updated about your progress. Thanks.

Thank you for the advice. When I get home I will try the first two and let you guys know what happens.

Originally Posted by Shaske87

I've been trying to figure this issue out for a while now with no luck. About two weeks ago I was going down the freeway and hit a metal shard and sliced my drivers side front tire and transmission oil pan. So lost all the fluid and had to be towed home. Replaced pan and refilled with dextron 3 like the big green sticker says. Now driving down the road it doesn't slip in any gear. The issue is during the gear shifts it revs up 500 to 1000 then drops and accerates normal. Fluid level is good. Does this warm and cold. I refilled the transmission correctly. Slim not sure if maybe the newer fluid is to blame or something else was hit that would cause this. My car is a 95 525i automatic. Has 220k on motor and body. Transmission has 110k

It sounds like low fluid level to me.

If you are sure the fluid level is perfectly correct, then it is possible the trans was physically damaged by the road debris. If there was enough force to poke a hole in the pan maybe the valve body took a hit. This is the cast alum part that you see whith the trans pan off. This is the main control for shifting, even the slightest crack or leak could cause poor shifting.

I have NO faith in the notion that adding new, correct, replacement fluid is the cause of your problem because it is too thin. I wouldn't bother with high milage mechanic in a bottle, it is highly unlikely it will fix your car.

Originally Posted by snowsled7

It sounds like low fluid level to me.

If you are sure the fluid level is perfectly correct, then it is possible the trans was physically damaged by the road debris. If there was enough force to poke a hole in the pan maybe the valve body took a hit. This is the cast alum part that you see whith the trans pan off. This is the main control for shifting, even the slightest crack or leak could cause poor shifting.

I have NO faith in the notion that adding new, correct, replacement fluid is the cause of your problem because it is too thin. I wouldn't bother with high milage mechanic in a bottle, it is highly unlikely it will fix your car.

High mileage tranny oil from multi million dollar brand name oil companies are most certainly not a "mechanic in a bottle" products and there is nothing overtly wrong with mechanic in a bottle situations, if actual mechanics such as Scotty Kilmer are prepared to advocate them in public in for appropriate situations. Obviously, such products will never be equal to a direct repair, but they solve the problem in enough situations to have proven their worth.

And we have seen situations on these forums where people with no prior damage to their transmissions, encountered gear slippage immediately after changing to new oil of the correct rating, and filled correctly according to the manual. Most of them posted here and disappeared without stating how they fixed it, but one german dude who specialised in buying E34s cheap from returning US servicemen and then selling it off at a profit, had this same problem with one of his cars and fixed it by switching to RP's high mileage tranny oil. He was one happy dude. That was over a year ago.

Anyway, the classic quick and dirty way to test if your have insufficient tranny fluid is as follows. Shift to D and accelerate to 30 mph and hit the brakes very hard...an e brake. When the car stops fully, release the brakes immediately and do not tap on the accelerator. Watch for how long the car takes to move forward. It should only take 1-3 seconds. If it takes something like 10 seconds, or an inordinately long period of time, you've got too little fluid.

The hard brake causes all the fluid to rush to the front of the transmission. It takes a few seconds to flow back to the back. The tcm will not let the transmission engage until it detects oil at the back of the tranny (or something like that). Its a fail safe. If there is too little oil, there will be nothing left at the back of the tranny when you hit the brakes. If you have enough oil, this will not be a problem.

Originally Posted by robertobaggio20

High mileage tranny oil from multi million dollar brand name oil companies are most certainly not a "mechanic in a bottle" products and there is nothing overtly wrong with mechanic in a bottle situations, if actual mechanics such as Scotty Kilmer are prepared to advocate them in public in for appropriate situations. Obviously, such products will never be equal to a direct repair, but they solve the problem in enough situations to have proven their worth.

So explain to me their worth when you admit in the same paragraph that it is not the same as a "direct repair".

Opinions vary on the validity of oil companies marketing claims. They have been suing each other for lying for decades. Accept the the claims they make at your own risk. Expect that the $100 you drop on trans fluid is most likely not going to fix the car, spend accordingly I say.

And we have seen situations on these forums where people with no prior damage to their transmissions, encountered gear slippage immediately after changing to new oil of the correct rating, and filled correctly according to the manual. Most of them posted here and disappeared without stating how they fixed it, but one german dude who specialised in buying E34s cheap from returning US servicemen and then selling it off at a profit, had this same problem with one of his cars and fixed it by switching to RP's high mileage tranny oil. He was one happy dude. That was over a year ago.

Very compelling evidence

Anyway, the classic quick and dirty way to test if your have insufficient tranny fluid is as follows. Shift to D and accelerate to 30 mph and hit the brakes very hard...an e brake. When the car stops fully, release the brakes immediately and do not tap on the accelerator. Watch for how long the car takes to move forward. It should only take 1-3 seconds. If it takes something like 10 seconds, or an inordinately long period of time, you've got too little fluid.

The hard brake causes all the fluid to rush to the front of the transmission. It takes a few seconds to flow back to the back. The tcm will not let the transmission engage until it detects oil at the back of the tranny (or something like that). Its a fail safe. If there is too little oil, there will be nothing left at the back of the tranny when you hit the brakes. If you have enough oil, this will not be a problem.

More very scientific evidence that will tell you exactly nothing, except that your fluid may be REALLY low.

Originally Posted by snowsled7

Quote:
Originally Posted by robertobaggio20
High mileage tranny oil from multi million dollar brand name oil companies are most certainly not a "mechanic in a bottle" products and there is nothing overtly wrong with mechanic in a bottle situations, if actual mechanics such as Scotty Kilmer are prepared to advocate them in public in for appropriate situations. Obviously, such products will never be equal to a direct repair, but they solve the problem in enough situations to have proven their worth.

So explain to me their worth when you admit in the same paragraph that it is not the same as a "direct repair".

You can ask scotty kilmer. I'm sure he promotes things that are totally useless and have zero benefit in all situations.

Originally Posted by snowsled7

Opinions vary on the validity of oil companies marketing claims. They have been suing each other for lying for decades. Accept the the claims they make at your own risk. Expect that the $100 you drop on trans fluid is most likely not going to fix the car, spend accordingly I say.

I have a mechanic who says that this (new oil causing slippage in an old transmission right after an oil change) might be possible. He has seen it happen. His theory is that the old oil was left in there for way too long before being changed, thickened too significantly, the tranny generated damage in trying to pump thicker oil around, and now cannot function with thinner oil. He feels that its not because of worn clutches that were being compensated for by the thicker old oil.

The point ???? He has noticed this exact same problem before, that of slippage right after an oil change, despite using only oem fluids and filling transmissions properly. His solution for his customers of course was to replace the transmission. He is not a forum member clearly.

Originally Posted by snowsled7

Quote:
And we have seen situations on these forums where people with no prior damage to their transmissions, encountered gear slippage immediately after changing to new oil of the correct rating, and filled correctly according to the manual. Most of them posted here and disappeared without stating how they fixed it, but one german dude who specialised in buying E34s cheap from returning US servicemen and then selling it off at a profit, had this same problem with one of his cars and fixed it by switching to RP's high mileage tranny oil. He was one happy dude. That was over a year ago.

Very compelling evidence

Of course, nothing on these forums is worth anything if it challenges one's superstitions.

Originally Posted by snowsled7

Quote:
Anyway, the classic quick and dirty way to test if your have insufficient tranny fluid is as follows. Shift to D and accelerate to 30 mph and hit the brakes very hard...an e brake. When the car stops fully, release the brakes immediately and do not tap on the accelerator. Watch for how long the car takes to move forward. It should only take 1-3 seconds. If it takes something like 10 seconds, or an inordinately long period of time, you've got too little fluid.

The hard brake causes all the fluid to rush to the front of the transmission. It takes a few seconds to flow back to the back. The tcm will not let the transmission engage until it detects oil at the back of the tranny (or something like that). Its a fail safe. If there is too little oil, there will be nothing left at the back of the tranny when you hit the brakes. If you have enough oil, this will not be a problem.

More very scientific evidence that will tell you exactly nothing, except that your fluid may be REALLY low.

Ermmm.....that was kinda the point here ?

I have no idea who scotty kilmer is, nor why I should care?

The mechanic trans theory is humorous at best. I suspect you made it up anyway. The stuff described simply does not happen, even if it was his theory

The fluid level is OK per the OP, it has been suggested repeatedly that he check it. I would reccomend the method in the Bentley manual over some sort of silly panic stop trans fluid check.... unless you follow up with your italian tune-up

Also did you service the tranny while the pan was off, adjusting the clutches etc? Would have been the ideal time. +1 on cracks and also (?) damaged or bent actuators and rods.

OP, the attached tables might help you get better visibility on this issue.