Auto not doing what it should!
Hoping for a simple solution to what may be a complicated problem:
Rebuilding a 1984 SWB Diesel Auto. All going very well so far, except Automatic gearbox. (The reason I bought her in the 1st place!).
Reluctant to go thru gears at all, not yet selected 4th, no matter how much cajouling.
Have made a half ar**ed try of checking fluid level + have topped up as best as poss. No joy.
Should say, the old girl lay quite still for 7+ years after blowing her head. Running as sweet as anything now though. Wondering if lie up could be to blame.
Anyone experienced similar or can offer advice?
Cheers
OK first things first, I’m certainly no expert when it comes to auto boxes! I would however guess the lay up could have resulted in the seals hardening and hence lack of hydraulic pressure to operate the valves within the box correctly. So suggest you change the fluid and filter (about £14 for a genuine MB filter from memory). Get some cheap fluid and maybe flush it through a couple of times.
I have had some success with seal conditioning additive in the past. Wynn’s / STP from any motor factors.
Last ditch attempt, no money back guarantees on this one! Fill with diesel run through gears but DON’T attempt to drive. Then drain and refill with proper fluid. I have never attempted this but have been told first hand by a work colleague who used electrical insulating oil (pretty similar to diesel) and fixed a totally non-operating auto box.
Good luck.
Russ
Ah yes Martin,
The classic "Italian tune-up" as my mate Clive ( being a traditional time served mechanic ) calls it and especially effective for vehicles owned and driven by little old ladies or men in flat caps, generally following a request for a service because said vehicle seems sluggish/just not going the way she should, but being an honest soul he would have the decency to change oi/filter/plugs if necc. before he revs the nuts off it.
Presume the Diesel attacks & swells the seals, sounds a bit of an "Arthur Daly" cure prior to flogging to a little old lady or a man in a flat cap!
Glad to hear you have her up & running btw.
Marcus
58mph in 3rd…….in a diesel auto, wow didn’t think they would rev to 7000rpm :D certainly cleared some soot out if nothing else.
Forgot to mention to make sure you drain the torque converter (thanks to Roly for informing me of that one). It holds about a litre of oil and you drain it by undoing an allen key on the torque converter housing, 6 or 7mm from memory.
Hi Russ,
Sorry took so long to reply, but have just gotten round to this one!!.
Got the Auto sump off, jeeez a lot of fluid!! Half filled a bucket.
Reread this string, and picked up on the torque convertor drainage. (had forgotten). My question is, when refilling the system, does the torque convertor receive its share of fluid from the sump - or is it filled separately?
Hope you can help. BTW, how many litres does this old girl hold?
Cheers
Martin
Torque convertor gets its fluid directly from the box. No separate filler, but certainly separate drain req'd. Level needs to be checked hot. I'll look for capacity
58mph in 3rd??.in a diesel auto, wow didn?t think they would rev to 7000rpm certainly cleared some soot out if nothing else.
Just like back to the future.... at exactly 58mph (indicated I hasten!! LOL) she pops. And yes, smokescreen volumes!! :D
Looks like I may have solved this one!!
All to do with vacuum pipes!!
Fed direct suction (Pinched from ignition shut off) continuously to gearbox. Changed thru all gears sooooo smooth as to be imperceptible!! Hoorah!! :D
Not all roses though, now going as slow as a pig, need to go thru gears manually to achieve acceptable forward motion, which kind of defeats the purpose. Hoping someone has a diagram, or knowledge of the correct layout of vacuum pipes for this old girl. Undoubtedly been mixed up somewhere along the lines.
Assuming the layout will be identical to her petrol sisters, with the exception of the fuel pump cut off.
Cheers for now, a relieved G wagoneer :D
Is it changing to the next gear too quickly? Try adjusting the cable that goes to the gearbox connected to the accelerator cable. Tightening that changes the change point. On mine the cable should just have the slack taken up at idle.
I'll check that Roly, thanks.
Chuffed its not to be a new gearbox either way.
Appreciate your earlier help on this.
Cheers
Nope!!
Pretty sure its the vacuum pipe layout now.
If anyone can take a snap of a functioning system, Diesel preferrably, it would help immensely.
Cheers
Hope these pictures help someone to get in touch with a solution. My local MB garage are scratching heads!!:
Please ignore spelling of throttle... getting old!!
Martin,
Perhaps I have been "dreeagh" on this one as I assumed you would need a photo of a similar model diesel, but anyway are you sorted or not ? I will take photos of Van this evening and attempt to post tomorrow if you still require?
Cheers ,
Marcus
Thanks Marcus,
Hadn't thought of the PUCH to be honest. If it has that mechanical vacuum linkage atop its rocker cover (and pump) then it may very well be useful.
I note YOU are now able to post snaps on here!!
by the by, Grey G Wagen away at mo, potential for sale in its entirety. You have 1st shout rites if sale does not go ahead on front winch.
Cheers
Marty
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Hi Russ,
1st, thanks for taking the time to reply.
Took the old girl for a longer drive today, (Over here anything more than 5 miles!!), and remembered what an old Mechanic friends' remedy to most ails was:
"Drive it out of her!!" (in a broad Belfast accent.)
Took his advice and at 58mph she finally slipped effortlessly into 4th. Had to rev the proverbial nuts off her to achieve this of course. After change up she got to 75 without any further fuss.
Not quite right yet, but hope at the end of the tunnel. Need her to change a lot sooner.
Will add the conditioner and change filter and fluid as suggested anyhow. Glad to have at least got it partially sorted - didn't fancy the Diesel last ditch, LOL.
Cheers and thanks again.