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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 15:36:43 GMT
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I'm still having trouble with the slush box on the BMW (525TD e34). I can't complain too much, as it's the reason why I ended up with the car in the first place, but I'd still like to fix it. I changed the ATF, filter and sump gaskets on the box last weekend, and it seems the problem has got worse, not better! It changes much smoother now bit this problem persists! So then. To the problem... When the car is at a rest, either at a junction or lights or whatever, I go to set off and the revs rise, car goes nowhere until it slams into gear and takes off. I never move the selector from the "D" position. It seems like it jumps out of gear when slowing down or at a standstill? All other gear shifts are fine and once it's underway it's faultless. I'm thinking that perhaps there's a sticking valve (between 1st and 2nd?) or a blockage, but I can't think why fresh ATF would have made this problem worse. It doesn't happen every time - perhaps once or twice each journey. The gearbox is the 4L30E General Motors unit, as found in Omegas, Isuzus, Hondas, BMW's... loadsa stuff. The old ATF was dirty but not burnt. There wasn't an excessive amount of metal particles in the sump, and I was as clean as I could be during the "operation" so as not to get dirt in the workings. I know auto boxes are mysterious things, and a lot of people have recoiled in horror when I mention auto transmissions... but I hoped there might be someone on RR who knows? I'm cleaning out the gear selector switching. This can cause the gearbox computer to get the wrong gear (or none at all) but the symptoms of this seem to be with selecting overdrive rather than the problems I'm experiencing, so I'm really just doing it as a matter of course, and not expecting it to fix the problem. Any ideas?
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mym
Part of things
Posts: 443
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Apr 28, 2009 15:46:14 GMT
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sounds like the ECU is putting the gearbox into neutral to save fuel at a stop, then when you pull off, it puts it into gear, which is why is slams in as your trying to accelerate.
would be worth checking with someone in the know, or someone at BMW to see if there is an ecu update, or an option that can make it stay in drive rather then going into "N"
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Apr 28, 2009 16:06:40 GMT
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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 16:37:40 GMT
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Thanks for the replies . The ECU shouldn't put the box in neutral, I don't think it's that clever. I don't know why it's jumping out of gear - it only happens at very slow speeds, which leads me to suspect something around the 1st-2nd solenoid (I sound like I know what I'm talking about here but I really don't... ;D) I've downloaded a technical manual for the 4L30E gearbox but it's aimed at transmission techies and I have only rudimentary knowledge of slushboxes! Sammm - thanks for the links, I might drop them an email and see if they can shed any light on it. The GM trans is quite a common one so should be familiar to a lot of gearbox techies. It's just an annoyance really - doesn't happen all the time, and I'm pretty confident that it wouldn't leave me stranded anywhere or get any worse. The clutches are in good order I reckon. It's strange that the new fluid has amplified this problem though...
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harris66
Part of things
drive it, break it, fix it and make it quicker!
Posts: 699
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Apr 28, 2009 16:50:44 GMT
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i know this may sound obvious but is the fluid level correct? i beleive you are suposed to check the level with the engine running?
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1.2 corsa daily, 1.8t a4 avante, 6.3ltr austin a40....
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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 16:56:59 GMT
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I know this may sound obvious but is the fluid level correct? I beleive you are suposed to check the level with the engine running? Well, we checked on Autodata how much should be put in after a filter / ATF change and it said 3 litres. 3.5 went in in the end but it may be worth me checking it again. Just to be sure. There's quite a narrow temperature range that the trans needs to be at before it can be checked (with the engine running, in N or P). Oh and it has to be checked by undo-ing the bung on the side, as it's supposed to be sealed for life (fun!) and has no dipstick. ;D
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mym
Part of things
Posts: 443
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Apr 28, 2009 18:38:25 GMT
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i know that certain volvo's used to shift into neutral when at a stop, so it is a possbility.
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Apr 28, 2009 18:39:01 GMT
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i had an audi 80 auto ages ago with a similar prob, i did the same as you but still no joy, i ended up getting a recon box for it coz my local auto specialists told me it was probably due a blockage in one of the oil ways. they did suggest running some special flush through the box to try to clear the blockage, but i got a cheap box from a breakers in the end.
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'90 Audi B3 Coupe 2.3 Auto [gone] '92 Audi S4 Avant 2.2 AAN Turbo Auto [gone] '93 Audi 80 Avant 1.9TDi [gone] '96 Audi A4 Avant 2.6 Quattro [gone] '97 VW T4 1.9td LWB [gone] '03 Skoda Octavia 1.9TDi [gone] '05 VW T5 Shuttle LWB 1.9TDi '15 VW Caddy Maxi Kombi 1.6TDi
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Apr 28, 2009 18:42:53 GMT
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has it got vacumn hoses on it running from the engine? they can cause some odd issues if not connected right or if they are leaking or blocked, i wouldn't think the box should go into neutral by itself when you stop or it would make hill starts a right pain.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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Apr 28, 2009 19:26:17 GMT
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Do what more and more people do over here, re-engine the thing with a cheap SBC and sturdy transmission.
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Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com
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Apr 28, 2009 19:33:38 GMT
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eeek!! you only put 3.5 litres in? no wonder its piddling about!!! correct procedure for reffilling is as follows, get car up in air on ramps and axle stands or a decent ramp if you have access to one? with someone in the car and engine running get them to go thru all the gears from park waiting a few secs in each one I.e. p,r, d1 d2 d3 then slowly all the way back to park, when its in park then you undo the filler plug, and pour atf in till it runs out of the hole repaet the gear selcting with the plug back in and then remove the plug again, if no fluid comes out then put more in, until it just rickles out, test drive and be amazed at the difference in the box,s behaviour!!
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Last Edit: Apr 28, 2009 19:39:18 GMT by rwdrules
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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 19:39:23 GMT
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There's a good possibility it might be a blockage, maybe making a ball-check valve stick or something. A flush could dislodge all the curse word - and it would change all of the ATF instead of just the partial change that dropping the trans fluid achieved. A professional flush sounds pricey though, and the Benz needs love and money throwing at it. There's no vaccuum pipes as it's all electronic, drive-by-wire, computer HAL-9000 type stuff. So much for my "sensible" daily not taking up my spannering time! ;D 'Fraid that's an oxymoron this side of the pond, Blitzy.
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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 19:41:49 GMT
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eeek!! you only put 3.5 litres in? no wonder its piddling about!!! correct procedure for reffilling is as follows, get car up in air on ramps and axle stands or a decent ramp if you have access to one? with someone in the car and engine running get them to go thru all the gears from park waiting a few secs in each one I.e. p,r, d1 d2 d3 then slowly all the way back to park, when its in park then you undo the filler plug, and pour atf in till it runs out of the hole repaet the gear selcting with the plug back in and then remove the plug again, if no fluid comes out then put more in, until it just rickles out, test drive and be amazed at the difference in the box,s behaviour!! Well, I put the prescribed 3 litres in, but then continued until it overflowed through the hole as advised. Then warmed the car up for 45 minutes, left it in neutral, undid the filler bung and fluid was trickling from the hole... so I'm guessing it's about right?
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Apr 28, 2009 19:42:18 GMT
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IS it going into neutral, or is the torque converter faulty leading to a really high stall speed? Generally they are supposed to start taking up drive at very low revs but a broken one can act like a drag racing trans and grab in at 4000rpm.... PS, I know next to nothing about BMW specifics, as my last attempt at bimmer diagnosis proved
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To get a standard A40 this low, you'd have to dig a hole to put it in
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Apr 28, 2009 19:46:52 GMT
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thismay be of no use whatsoever so sorry in advance...but my wife has a merc c180 elegance 98 on an sreg.. weve had the car 4 years and have never changed the engine oil or anything else come to that, ..about 2 months ago it became lumpy to drive and just didnt feel as nice as it used to,it then started to drop into 1st gear from2ndas you slowed down at junctions etc ,i spoke to afriend who owns a gearbox firm and he said sticking valve £300... iwent out and bought new plugs oil and all the filters ..air ,oil fitted them and all seems ok ...as a precaution we now go through the gears whilst waiting for i to warm up and all seems fine? ?
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Apr 28, 2009 19:47:58 GMT
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eeek!! you only put 3.5 litres in? no wonder its piddling about!!! correct procedure for reffilling is as follows, get car up in air on ramps and axle stands or a decent ramp if you have access to one? with someone in the car and engine running get them to go thru all the gears from park waiting a few secs in each one I.e. p,r, d1 d2 d3 then slowly all the way back to park, when its in park then you undo the filler plug, and pour atf in till it runs out of the hole repaet the gear selcting with the plug back in and then remove the plug again, if no fluid comes out then put more in, until it just rickles out, test drive and be amazed at the difference in the box,s behaviour!! Well, I put the prescribed 3 litres in, but then continued until it overflowed through the hole as advised. Then warmed the car up for 45 minutes, left it in neutral, undid the filler bung and fluid was trickling from the hole... so I'm guessing it's about right? nope you havent filled the valveblock doing it that way you must select all the gears to fill the oilways and then check the levels!! the box will burn out if you keep using it the way you have filled it mate!! get it on the ramp and redo the way i described please!! run loads of these gm boxes and they do have to be done this way!!
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Automatic gearbox gurus?BenzBoy
@benzboy
Club Retro Rides Member 7
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Apr 28, 2009 19:57:40 GMT
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Well, I put the prescribed 3 litres in, but then continued until it overflowed through the hole as advised. Then warmed the car up for 45 minutes, left it in neutral, undid the filler bung and fluid was trickling from the hole... so I'm guessing it's about right? nope you havent filled the valveblock doing it that way you must select all the gears to fill the oilways and then check the levels!! the box will burn out if you keep using it the way you have filled it mate!! get it on the ramp and redo the way I described please!! run loads of these gm boxes and they do have to be done this way!! Thanks for your advice - looks like I'm busy tomorrow then! ;D I've read that the oil needs to be within a specific temperature range to get the right level too. Am I right? Just to be clear, this is how we filled it: Filled up small sump before bolting it up. Fitted filter and large sump. Put in ATF (Dexron III) until it overflowed. Started car, went through gears 6 or 7 times. Left to idle for 45 mins (probably went through gears a few more times) Left car running in Neutral Undid bung and refilled again until it overflowed. Did it up. Test drove it. It selected gears really smoothly. But now you got me worried.
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Apr 28, 2009 20:01:50 GMT
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'Fraid that's an oxymoron this side of the pond, Blitzy. They're around 2000UKP brand new in the UK, mate. Not rebuilt, new. I'm certain used and rebuilt SBCs could be had for less. No, you'll not get one for 400 S&H greenstamps or 80 Werther's wrappers, but a new GM 350 V8 for 2000UKP is about as cheap as it gets in reality. Not much more than is charged here, actually.
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Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com
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Apr 28, 2009 20:04:18 GMT
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Just re-read your OP, and I've convinced myself - you still have your original fault from BEFORE you changed the oil.... so incorrect fill procedure is unlikely to be the cause (but might be making it worse)
I go to set off and the revs rise, car goes nowhere until it slams into gear and takes off.
which sounds a lot like the torque converter to me
It seems like it jumps out of gear when slowing down or at a standstill?
this bit confirms it too. (I think....)
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To get a standard A40 this low, you'd have to dig a hole to put it in
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Apr 28, 2009 20:06:37 GMT
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nope you havent filled the valveblock doing it that way you must select all the gears to fill the oilways and then check the levels!! the box will burn out if you keep using it the way you have filled it mate!! get it on the ramp and redo the way I described please!! run loads of these gm boxes and they do have to be done this way!! Thanks for your advice - looks like I'm busy tomorrow then! ;D I've read that the oil needs to be within a specific temperature range to get the right level too. Am I right? Just to be clear, this is how we filled it: Filled up small sump before bolting it up. Fitted filter and large sump. Put in ATF (Dexron III) until it overflowed. Started car, went through gears 6 or 7 times. Left to idle for 45 mins (probably went through gears a few more times) Left car running in Neutral Undid bung and refilled again until it overflowed. Did it up. Test drove it. It selected gears really smoothly. But now you got me worried. hmm thats nearly right, but you should have it in park and undo the bung as soon as you have been through the gears, when in neutral the valve block isnt being pressurised hence not using any atf from the sump, although i wouldnt think its very low i reckon it will be for sure, the selector switch on these is known to give trouble too, they fill up with gunge and can play havoc with gear selection, its easy enough to remove and strip and clean then replace but make sure you get it in the correct position, the procedure for this should be in you manual involves using a drill bit to get it bang on!!
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