E34 535i transmission problems
 

I have a 1990 535i, and my automatic transmission started giving me problems today.

It started out while I was driving this morning.

I noticed it slipped when i accelerated, and when I tried to park it, it would slip again in reverse and won't catch.

Later on that day, reverse started working, but in drive it slipped, then it got so bad it barely budges, and now I get a trans error code or something on the dash.

Is my trans gone or is it some computer problem?

Nick

Hey Nick. The first thing you need to do is check the tramsmission fluid level. The Bentley manual has this described well. It is not as simple as it is on an american car with a dipstick. I can't remember if yours has a dipstick. If it does, be glad. If the fluid is low, top it off. If it is at the proper level, then you have to inspect it to see if it is real burnt. If so, then your transmission is likely toast. Unfortunately, the auto tranny is not as strong as the engine.

Hope this helps.

Yeah, I have a dip stick, and I recently had the fluid changed, so its fine.

I agree. The auto trans in BMW's in general are junk.

I've been driving BMW's for over 20 years, and one thing I experienced their auto trans is junk just like any other brand.

I never had any problems with BMW manual transmissions. They are like bullet proof! I had never replaced one.

Oh, well, i'm tired of rebuilding the trans. This car has become a money pit. I will put this piece of sh*t up for sale.

regards
Nick

If you recently had your fluid changed, and then you began experiencing these problems, you have encountered an unfortunately common situation.

The old fluid would have been much thicker than the new one. This actually worked to reduce or prevent slippage between worn clutches. The tradeoff is the your transmission is less efficient due to thicker fluid, so your mpg will fall. Further, wear will be accelerated due to the old oil.

When you changed to new oil, it was too thin visavis the worn transmission, to prevent slippage.

The solution will be to either switch back to the old oil if you kept it away, or change the oil to a thicker blend. Alternatively you could try one of those friction modifiers that they sell off the shelf which is supposed to "reduce slippage". Since you have a dipstick, perhaps you'd like to try that by pouring it in through the dipstick to see if it helps.

The next best bet would be to try changing the oil to a clean oil but which is thicker than what is recommended for your transmission.

There is an outside chance that you actually used thinner fluid than what is recommended for your tranny and your tranny is actually ok. Very long shot but do rule that out if possible.

Download the soft copy of the E34 Bentley manual for details about transmissions and recommended oils.

You'll be able to have a good discussion about these elements with a seasoned indie mechanic.

In any case, your transmission is probably not in good shape. It is unlikely that you'll be able to sell your car without taking a huge haircut. Considering the size of that haircut, you might elect to keep it and try to salvage the transmission in the ways I've described above.

Unless, of course, its really no longer worth your while.

I had the trans rebuilt about a year ago, and not sure what type of fluid was used. What's weird is, at first reverse went bad, then it came back to life, but Drive dropped dead, what's that about?

Nick

If your transmission was rebuilt, then my earlier comments do not apply. Did you use oil that was too thin ?

It might also be your transmission range switch.

The Bentley manual has a checklist of transmission problems and their corresponding causes. Please study that and let us know how it develops.

I dont have the bentley.

I don't know what type of fluid was used, but I remember topping off the trans with synthetic trans fluid when the trans was leaking.

If you rebuilt your transmission just one year ago, why did you change your oil recently ? They would have put in new oil after the rebuild, and that oil lasts for 100k.

Here's the bentley manual :

http://www.mediafire.com/?ijviizbkk26be

The trans had a slow leak, bad gasket I guess.

Thanks for the link.

Do the stomp test, read the codes, clear the codes (using the stomp test or by disconnecting the ecu for 5 minutes) then restart the car. Sometimes, that fixes things.

If it does, go have your gasket and transmission looked at with your tranny winched up. Goto the fellas who rebuilt your transmission. They screwed up the gasket fix obviously. Have them fix it for free. Enforce your rights.

ok, thank u

Transmission gaskets do not leak after just one year if they were done properly. Obviously, the reason why you had been losing oil was because of this leak. Why did you check for a leak ? Did you spot an oil patch, or did you just happen to check the dipstick, and then notice that you were low ? Or did you experience any transmission problems ?

Did you top up enough transmission oil ?

You should go back to the shop that did it. It doesn't matter it if was a year. They are liable due to the nature of the repair.

I seen an oil patch, so i took it back. The mechanic claims it was over a year, past the 1 year warrante, basically he did not honor his gaurante.

Yes, I topped it off.

For the future I will try and avoid old cars and dishonest mechanics.

Go back and yell at him again. Now you've got gearbox problems. He might have put it there.

I have no idea how you came up with this, and it certainly isn't common. How do you figure the old fluid was thicker when you don't know which fluids have been used in the trans? ATF is pretty consistent stuff, changing it should never produce ill effects, that is no more than internet legend.

Actually, what is wrong is that the trans pump can no longer maintain enough pressure for the trans to function properly. THIS is pretty common on older auto transmissions.

This trans problem has nothing to do with the thickness of the ATF. I am not sure where you are finding thicker and thinner versions of ATF???

The trans needs a rebuild. For about the same money, and probably less you could swap in a five speed and be done with it.

Hi Snowsled7 and welcome to Bimmerfest !

All that I've written about (people having slippage problems after a regular oil change and fixing those problems after changing to a thicker oil) has been seen and done on these forums. That's where I learned about it.

You're obviously right about the problems that old transmissions have, and what I suggested earlier is not applicable in the OP's instance as he clarified later, but what I've written about has been experienced and solved on these forums by more than one individual.

Its so counter intuitive that I really could not have invented that. I get my info from here.

And there is a thicker kind of tranny oil, that someone tried after changing his old oil and then getting slippage issues, and then fixing the problem..... I lost the link to the actual post. I believe it was a royal purple or valvoline high mileage transmission oil product. It was some dude in Germany crowed about buying E34s for free from returning soldiers or something..

If I find the link to that thread, I'll post it up here again.

Yup. It's a given, automatics always require a lot more maintenance-per-mile than a manual. Not exclusive to BMW. But I gotta wonder, if you knew this before hand, why would you think this car would be any different? :dunno:

Sporty cars, automatic transmissions, and spirited male youths is certainly not a reliable combination.

The cars are pushing over 20 years now and many have well over 130,000 fairly abusive miles.

Look on youtube for example...almost every video of someone mugging for the camera is doing donuts, extended burnouts, and generally driving like an ass with an automatic. This applies to any make. Folks can only beat the snot out of something for so long before it fails.

I can appreciate that feeling. Hard broke cars suck big-time. Sounds like it's just time to move on to another project. :roundel:

You can not fix a worn out automatic transmission by changing the fluid. Switching to a different specification of ATF from what is specified is truely poor advice. Auto transmissions are fairly sensitive devices with specific cooling and friction needs. Deviating to a supposedly "thicker" fluid simply is not a sound solution, if such a fluid even exists.

If what you posted was gleaned from an internet forum, you should consider the source. That is not accurate information. There are tons of myths on the internet about auto transmissions and fluid. You are perpetuating one of them.

Obviously, it is not a way to fix the transmission. That's so self-evident that i did not state it.

It is, however, a way to enable you to forestall the inevitable rebuild. For some people, that's an option they would be glad to exercise if they could.

I am considering the source. Real people like you and my facing real problems and trying real solutions and some happen to work. From that set of facts, we hypothesise the likely reasons why. That's all.

Come one. Its just like switching to slightly thicker engine oil for very high mileage engines to improve piston ring sealing. I got that from the internet too.

After some time of diligent reading, asking questions, and careful alignment with certain posters who clearly know what they are talking about, you tend to build up some knowledge of the thing.

This is incorrect, it is a complete waste of time and money to try and replace the fluid on a failed auto trans. It has been tried millions of times I am sure, always ending up in the junkyard or with a replacement trans. It is misleading to suggest this will work, it will not.

You do realize that ATF doesn't come in various viscosities right? ATF comes specified for specific transmissions, not in different wieghts like motor oil.

Thicker motor oil will not help seal worn piston rings. Typically people use it to bolster fading oil pressure in worn engines with large clearances.

So you have read about it on the internet.... I on the other hand have decades of hands on mechanical repair experience. This is my sixth BMW among dozens of cars I have owned and worked on.

I tell you what, I'll find that post and I'll post it up here for you. Maybe the OP is still around and we can talk about it with him and you can trace the root causes of his issue. I'll be glad to change my tune if an expert can point out the apparent flaws in the evidence.