Auto transmission problem - reverse gear + vibration

[alang1990]

Hello there. Please help me ! 1990 5hp18 transmission. I have a sudden problem a week ago. Two problems. First the reverse gear doesn't seem to engage when switching from N to R. Before it used to bang a little bit. Been that way for N to R and N to D for the past 10 years. Now when I switch from N to D, the usual small bang is there. But now switching from N to R, there is zero bang at all. Now when I switch it to R hardly moves at idle. When I give it some gas about 1000rpm, the car moves backward and basically normal speed. Does not move or barely moves at idle speed 650rpm. So the gear must be engaging because it moves but does not move immediately when I switch from N to R and don't touch the pedal.If i'm on a forward slope, engaging R the car moves forward. I need to give it gas for it to move back. Gear shifts forward and downshifts during driving appear normal.Problem 2. Now at 20mph and onwards there is a vibration coming from the car. Pretty bad I initially though it was a misfire but plugs and coils are alright I checked. It continues until around 55 and then becomes a small buzz after the lockup clutch engages. Downnshifting during slowdown the vibration happens again. Have done the stall test. No vibration at the maximum point.Interest thing stall test. When I did the stall in D, the maximun point was about 2000rpm. When I did it in R, the max point was much higher - around 3000+ rpm. Oil was just changed. 5 litres came out brown colour. New dex 3 put in. Manual says 9 needed but only 5 came out and 5 went in. Oil levels properly checked after that. btw oil levels were not low did a check about 6 weeks ago and that was good. Filter not changed. What am I looking at here? What is the problem ? Is it just the valve body? Or the whole thing? What is the vibration all about ? Thanks for your time.alan

[shogun]

Troubleshooting BMW A5S 310Z ZF 5HP18 http://www.bimmerboard.com/forums/posts/1214743/
Maybe you drop the valve body and make an overhaul, even a trans flush will not entirely clean the valve body and the filter in front of one of the solenoids, also on the 5HP18 it is known that the plastic balls inside the valve body get smaller http://s248.photobucket.com/user/dwh...?sort=3&page=1
Best would be if you find a shop with a good diagnostic tool which can also find trans codes, that means a cheap Peake tool or something similar is not good enough

[alang1990]

Troubleshooting BMW A5S 310Z ZF 5HP18 http://www.bimmerboard.com/forums/posts/1214743/Maybe you drop the valve body and make an overhaul, even a trans flush will not entirely clean the valve body and the filter in front of one of the solenoids, also on the 5HP18 it is known that the plastic balls inside the valve body get smaller http://s248.photobucket.com/user/dwh...?sort=3&page=1Best would be if you find a shop with a good diagnostic tool which can also find trans codes, that means a cheap Peake tool or something similar is not good enough

Thanks Shogun. So does it sound like a valve body issue ? Even the vibration ? Exactly what is going on there to cause this? Or do you think its a clutch issue which won't be fixed by anything ? Do I have a problem with my synchroniser ? Is there a simple way to rule things out ?


I have a spare VB I can dump it in with new oil and filter and see what happens. Will also do the full flush procedure you posted in the other thread thanks a bunch. E34 525 1990 will update.

[shogun]

The vibration could come from the driveshaft, check center bearing, transmission mounts, engine mounts etc, the drivetrain must be straight from front to rear. http://www.bmwe34.net/E34main/Mainte...terBearing.htm
Also check the selector valve in the valve body, they tend to brake, recently I read about many cases: ZF 1056 327 173 01 http://www.thectsc.com/products/sele...alve-84-3.html
if that is broken, people believe they shift, but nothing happens inside the valve body. ZF has a new version with better material nowadays.

Please update your profile with built year/month, model, and I assume it is a Euro version, as you talk about a 525 with 5HP18

My Cars: E34

[alang1990]

OK I will check the driveshaft for signs of wear. Brought the car to a transmission shop they took it for a test drive and said the clutches are gone and it is unlikely to be a vb issue. Must rebuild or replace.

Can I ask a question. The severe vibrations that I get when I drive forward, which only happened together with this transmission issue. Is this definitely not due to the gearbox ? Or can some kinds of gearbox issues also cause bad driveline vibration?


Thanks. Alan

[shogun]

In case the transmission will be rebuilt or you buy a reman trans, I would in any case also change the center bearing, flex disk, engine mounts and trans mounts, then the whole drive train is straight again. Sometimes even the trans sellers insist that also a new torque converter will be installed, to avoid that abrasive material within the TC collected from a blown trans damages the new trans, otherwise they might refuse warranty.

What did the transmission shop comment on the vibrations?

Before you buy a reman trans, I would suggest you visit another transmission shop and ask them for their comments. Shops sometimes are quick to say a reman trans is needed. A second opinion might help.
But as I cannot personally test your car, it is difficult to diagnose via the net.

[alang1990]

Thanks I will visit another for sure. The one I went to said the vibrations are probably driveline, bearings or guibo, and that they happened together with the transmission issue because of sheer coincidence. They put the gbox into neutral and throttled up with no vibrations from the engine so they said the vibrations are not coming from the engine.

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Shogun, can I assume that vibrations during driving which stop when I let off the gas, cannot be due to a gearbox's internal fault ?

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The vibrations are hard and only become a light buzz at the top gear. They also appeared together with the R gear issue. Thanks.

[shogun]

Most probably the vibrations come from the driveline like center bearing, guibo, trans mounts, engine mounts. Inspect the center bearing, maybe the rubber between bearing and outer metal ring is cpl. destroyed. I once had a vibration on the driveline abt. 10 years ago, I was on a business trip, wife went to a shop, they said, needs complete new driveline. Told wife to wait till I come back, checked it, only the 2 bolts holding the center bearing were lose, installed it correct with pre-load, works still after 10 years without vibrations.

[whiskychaser]

The ZF documentation says the total ATF is 7.8 litres and 3.2 litres without the TC. But if you simply drain and refill, the 5 litres you mention is about right. That is assuming that the ATF is at the correct temperature. Maybe confirm that the filter was changed too because that is not clear.
It is also worth confirming that the shift cable is correctly adjusted. It controls the manual valve which Shogun mentioned. If you want to replace the manual shift valve, you can do so without even dropping the valve body - you just need some longer screws. But you need to make sure it is hooked up to the shift mechanism again when you refit or you will get a box full of nothing.
Doing a diagnostic check would be very useful but the E34 system is ADS, not OBD. Also remember that some of the cables (Carsoft) don't have all the pins wired. The result is that INPA or DIS cannot identify the car automatically and you have to input the cars details manually. It works but isn't really as reliable.
You might get vibration from a number of sources including tyres and the guibo. But you might also get it if the TC lockup solenoid is faulty.
This may sound a little odd but does the car slow down normally or does it feel like somebody is applying the brakes when you let your foot off?

[alang1990]

Hi Whiskeychaser,

Thank you or your reply. I just had the car jacked up to check on the driveline vibrations. Guess what I found :



Busted guibo.jpeg

The guibo itself showed many cracks, but one bolt on the guibo had disappeared completely. This must have coincidentally happened when the transmission issued happened. That's why I did not feel an increasing vibration over months. It was sudden. Workshop opined that the rubber was bad, caused excessive vibrations which eventually snapped the bolt and sent it and its nut flying somewhere.

The transmission mounts were also torn - this was demonstrated for me. Engine mounts looked fine.

Now all of that except engine mounts are on order and will be installed in a few days. I'm very sure my driveline vibration issue will be solved after that. I'm super relieved it was not the driveshaft centre bearings or the transmission. On the whole it was a good morning.

Whiskeychaser, let me answer your specific questions. No transmission filter was not changed. That and the gasket are also on order and will be done together with a spare VB sometime next week. Its a vastly lower mileage one so should rule out the vb immediately. Oil will be fully changed according to the direct suckup method stated here. Dirty oil left behind and filter not changed will be ruled out. Lets see if that restores my transmission to its previous bangin' glory.

Gear shift cable was inspected just now and appears to be tight. I didn't read up on the procedure properly so this will be checked again next week during the oil change and gears being shifted etc.

Thank you for the enlightenment on the diagnostic issues. I'm not getting a star symbol on my dash so I doubt it is a solenoid or anything electronic on the vb. Could be clogged dirt or a broken piston as Shogun suggested. I will open up the vb after removal and check that. It should be interesting.

There is some vibration after lockup but it must be the mangled guibo. I did the stall test in D and there was no vibration - so torque convertor is ruled out.

Would like to confirm if the stall test in D and in R should show stalling at the same rpm. My D stall is around 1900, my R stall is past 3000. If they are supposed to be the same rpm, then this result should indicate slipping R gear clutches. Would that be the correct conclusion ?

Thanks everyone for your insights. I guess I worried for nothing. Car's been a moneypit over the years.

Next thing to check will be the Fusible Link B for my other issue (other thread). I'm looking forward to a fix there. It might in fact clear up a lot of other stuff that goes on in the cabin too !

Thanks Alan

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Tyres, shocks and front suspension components are good - were fixed over the past 4 months. Rear dogbones are torn but I can live with the squat during the initial D shift.

[whiskychaser]

Sounds like you have found the smoking gun as far as the vibration is concerned.

I don't have a spec for a stall test in reverse but it looks too high. It confirms what you knew already - you have to rev the engine more to get the car to move. There are a few obvious reasons for that - you haven't got enough ATF pressure, the clutches are going or the D/G drum is on its way out. You will probably find some odd shaped bits of metal in the pan if the drum is the cause. Best scenario would be that you have a lazy solenoid or valve sticking in the VB. A diagnostic test - or even a test with a meter - would show up the former. But if it is just gummed up, you will just have to clean it out.

I will pre-empt the question of replacement and say getting a used one is a lottery. You cannot pick any old 5HP18 and normally you would need to get one with the same number as you have now. Maybe check the plate on the side for your actual model number.

[alang1990]

Best scenario would be that you have a lazy solenoid or valve sticking in the VB.

From your lips to the bimmergod's ears.

The spare vb that I have has been tested and is guaranteed good. Bought it a few years back to see if it will solve my N to D/R bang, It didn't so I decided to keep it as a spare if it was ever required. Lets hope I don't have to contemplate changing the entire transmission. Thanks Whiskeychaser.

[whiskychaser]

Harsh engagement can be caused by a worn pressure regulator and it is the pressure spikes that can blow the D/G drum. Not what you want to hear but it is not rare. Hopefully, your spare VB was tested for wear too.