Auto box slipping in 4th!

[penderb]

My 1986 300 Diesel Auto 124 model has started slipping in 4th. I'm driving along 50/60/70/80 mph & suddenly I loose power, revs go mad for 10 seconds or so.
Then all fine. It's also intermittant. Only slips in fourth gear. Lately I've started using 2nd, 3rd, to get car moving quickly, as leaving it in "D", takes way to long to get going. Kickdown is very poor also, as is going up the gears via "D". Mileage on car is 280,000 miles. I've only owned the car since May, as I've also got the manual version of this model. I drive both, but mostly drive the auto. Gearbox oil level seems fine, plus oil colour is clear. I've read some of the posts regarding black boxes behind the battery & also the oil changes for the autobox.
I've had a look behind the battery, & I see two small black boxes, plus some big connection immediately behind the battery, which looks long & narrow. What are these? What tests\checks can I carry out first to confirm, if I need to go the route of replacing the Autobox, which I know can be costly, but I'm prepared to get it done, if I can definitely confirm it isn't something else.
Incidentally, it really went"mad" on the Motoway on Sat, had to pull over,stopped engine, lifted bonnet, smoke everywhere, as I tried to keep driving, before, finally stopping altogether, then, restarted car, went perfect for another 100 odd miles!!!

All info greatly appreciated.

Billy

 

[penderb]

Autobox slipping in 4th

Just wondering if anybody had any ideas on the below problem I posted in August? before I get the cheque book out? Is it definitely the box that needs a full overhall? It's been running fine for a good while ,but it's got worse recently, taking off from stationary when engine stone cold causes 1st to slip/judder until warmed up, then 1st fine. I've also noticed when cornering, box slips in 4th. Am I imagining this?? It does do it!!!

Any info greatly appreciated,

Billy

My 1986 300 Diesel Auto 124 model has started slipping in 4th. I'm driving along 50/60/70/80 mph & suddenly I loose power, revs go mad for 10 seconds or so.
Then all fine. It's also intermittant. Only slips in fourth gear. Lately I've started using 2nd, 3rd, to get car moving quickly, as leaving it in "D", takes way to long to get going. Kickdown is very poor also, as is going up the gears via "D". Mileage on car is 280,000 miles. I've only owned the car since May, as I've also got the manual version of this model. I drive both, but mostly drive the auto. Gearbox oil level seems fine, plus oil colour is clear. I've read some of the posts regarding black boxes behind the battery & also the oil changes for the autobox.
I've had a look behind the battery, & I see two small black boxes, plus some big connection immediately behind the battery, which looks long & narrow. What are these? What tests\checks can I carry out first to confirm, if I need to go the route of replacing the Autobox, which I know can be costly, but I'm prepared to get it done, if I can definitely confirm it isn't something else.

 

[penderb]

Autobox slipping in 4th

Just wondering if anybody had any ideas on the below problem I posted in August? before I get the cheque book out? Is it definitely the box that needs a full overhall? It's been running fine for a good while ,but it's got worse recently, taking off from stationary when engine stone cold causes 1st to slip/judder until warmed up, then 1st fine. I've also noticed when cornering, box slips in 4th. Am I imagining this?? It does do it!!!

Any info greatly appreciated,

Billy

My 1986 300 Diesel Auto 124 model has started slipping in 4th. I'm driving along 50/60/70/80 mph & suddenly I loose power, revs go mad for 10 seconds or so.
Then all fine. It's also intermittant. Only slips in fourth gear. Lately I've started using 2nd, 3rd, to get car moving quickly, as leaving it in "D", takes way to long to get going. Kickdown is very poor also, as is going up the gears via "D". Mileage on car is 280,000 miles. I've only owned the car since May, as I've also got the manual version of this model. I drive both, but mostly drive the auto. Gearbox oil level seems fine, plus oil colour is clear. I've read some of the posts regarding black boxes behind the battery & also the oil changes for the autobox.
I've had a look behind the battery, & I see two small black boxes, plus some big connection immediately behind the battery, which looks long & narrow. What are these? What tests\checks can I carry out first to confirm, if I need to go the route of replacing the Autobox, which I know can be costly, but I'm prepared to get it done, if I can definitely confirm it isn't something else.

 

[230K]

Hi

I would start by changing the transmission oil and filter use only MB filter and oil.
This is supposed to be done every 36K

230K

 

[penderb]

Hi 230k

Many thanks for input. As a footnote to this problem, while changing the Engine oil on Saturday just gone, I decided to dip the autobox(engine ticking over) and discovered it was very low, it took cicra 2 litres to get it back up to correct level! Doh!. I checked it some months ago & level was fine, seems I need to check it more often!! so, for some unknown reason, didn't bother checking it since.The topping up with the 2 litres has helped a small bit, but by no means perfect. I was just thinking then, before I seen your reply, maybe I need to go the whole hog and do a total oil change, filter etc, just to be sure. One day I'll learn to check the obvious first! I only have this car since May & there was no service history, so no idea how long since last oil change on Autobox. As my knowledge of autoboxes is low, I didn't think low oil and/or dirty filter could cause slipping?.....

Billy

 

[penderb]

Just an update to this. Firstly, while driving along, as usual about 40/50 mph, autobox in D, and as usual it dropped out of 4th gear, I immediately popped it back manually into 3rd, as it turns out I popped it back a "tiny" bit to strong. Guess what happened? only snapped the half shaft drive going from diff to left hand wheel! Ouch. Rare occurence, I believe. Now back driving manual 124,until my Garage fits another shaft.
But while I was sourcing a shaft, an independent Merc dealer suggested my slipping box could be the clutch bands in 4th gear failing, thereby requiring the box to be removed & overhauled.

Anyone agree/disagree?

Billy

 

[jberks]

Had similar slipping on an 100k '83 280E a few years back, oil and filter didn't help, needed a complete box rebuild. - ouch.

 

[Ger D]

Hi Billy, sorry to hear of your problems.
I might suggest that you talk to Fergus Conway, walkinstown, Dublin.
He comes highly reccommended for Merc Gearbox problems.
Hes on 01 450 2623. ( No relation!)
Let us know how you get on,
Ger

 

[dieselman]

I would say the box is on the way out. 4th is usually the first gear to go.
Check the vacuum modulator doesn't have a split diaphragm, because the smoke sounds like the engine is sucking the ATF out of the box.

Driveshafts also seem to be a bit popular at the moment and it always seems to be the nearside one, they just snap without warning.

 

[turnipsock]

After gaining an MOT the other day, my car seemed to be lacking acceleration. Tonight, on the way home, I came off the motorway and slowed at the roundabout which was clear. When I accelerated, the car took off like a Renault F1. From then on the revs were way ahead of the engine and things got worse but I crawled home with a que a mile long behind me.

Because this happened really suddenly I thought I better have a look before I got the overworked plastic out.

There is a vacum pipe from the side of the gearbox up to a switch thing near the battery, whats that for, because there is a big crack in it? When I took the pipe out it was really brittle and broke up even more.

Could this cause the problem?

 

[turnipsock]

Looks like my box is slipping in all the gears now, it won't even reverse!

Questions are:

Can I replace this myself in the driveway (even though it's going to takes ages)?

Where do I get a decent replacement box?

 

[landover]

Try sportscar breakers at newbridge Edinburgh for a box.It can be done in the driveway but a lot easier on a ramp inside out of the cold.

 

[turnipsock]

I forgot the important question, How much would a box cost? Even though that you sometimes get a six month guarantee with these, it's really worthless as the big problem is all the work changing the box.

Is there anywhere to get a recon box that I know will work? (I'm not sure the breakers is the best way to go as I may be going through this again next year sometime).

Reading through the haynes manual, it look fairly straight forward...it's just a load of work.

What size of socket goes on the crankshaft pulley?

What size of spanner goes on the 'prop shaft clamp nut' though I think it would be easier just to drop the whole cente bearing out?

I may invest in some ratchet spanners before I start this one.

 

[190]

Have you checked the fluid in the auto box? Is it still a red colour or has it turned brown. If it is still rd it is very unlikely it?s the clutches that are at fault is there any
Contamination of the oil like water and oil getting mixed I have seen the inner automatic cooler in the radiator being at fault it would be worth getting the box checked with pressure gages just to make sure it is the box and not the torque converter that?s at fault. Normally when the clutches are away the oil turns brown. Better getting the box reconditioned
Try this link they are good.
http://www.mackie-transmission.com/services.htm

 

[penderb]

Thanks for all info, have found a specialist with 30 odd years of auto experience & does a lot on Mercs......
Just to let you know, I've bitten the bullit on this & am going to a specialist for a full teardown, examination & a full rebuild of my own box. Will know next Monday what state the box is in, as it will be out of the car then & on the operating table! Will be interesting to see what the specialist has to say, but once the box is apart, I'm not"patching" it, it'll be a total rebuild as I do not wish to have to re do any aspect of it in the near future.

Billy

 

[penderb]

The latest in this on going saga:

Just got off the phone to the autobox specialist......

Auto box is totally shot

So bad, the gear trains are gone to, most all top gear bits burnt out, nothing left. may have a job getting gear trains, will know full exact details on Weds aftenoon,when he does a detailed checklist. May need to get 2nd spare autobox to source gear trains, wonder how good they'd be?!?!?!?!?!? more money!

On the plus side,though, It was full of oil!

Ah, the joys of motoring.

Billy

 

[Ger D]

Hi Billy, let us know how you got on and give us the name of your Independent Specialist if hes any good,

GerD

 

[penderb]

Finally

Back on the road. Box fully re conditioned. Nothing re usuable from original. Auto Box builder showed me all old parts, everything either massively burnt out, heavily worn, huge amounts of free play in gear trains, plus cracks in gear train housings. Car has 300, 000 miles on it, but Box guy told me it had been out of the car before on at least a couple of occasions!!. Somehow I assumed this was going to be it's first overhaul.
So how does it drive, I hear you ask?
It's an absolute pleasure to be able to put it in "D" and leave it there.
Up & down shifts actually noticable now, non existant before overhaul.
There is I suspect some wear in back axle/diff area as there's the tiniest of kick noise back there, very little now, but may need some work later on. Obviously early days yet, but there's a year's warranty with it.
The Cost?? keeping in mind absolutely every component in box was replaced, bits had to be ordered in from England, it came to ?1200 Euros.
Auto Box specialist(specialises in autos only) was telling me, the amount of C class & W210 models in for work with him, all the electronics on those boxes are a nightmare. He's seen people coming in, walking past 210's, to have a look at the old robust 124's!

Time will tell.......The joys of motoring

Billy

 

[Ger D]

So Billy, you got sorted, Glad to hear that.

Whos your Auto specialist? Would like to know for future reference.

Thanks
GerD

 

[penderb]

Ger

Yeah, sorry I didn't put guys name in. Tom McManus of Borg Werner ATC, near Croke Park, contact number(01)8363155. small operator, 2/3 guys working. can't think of exact address, don't have invoice to hand... literally down a street of houses, drive up back lane, small place, but an Aladdins cave, when workshop doors open up. Very nice man, good "vibe" from him. It's my first dealings with him, so time will tell, but he's in the business about 30 odd years, can't be that long in the game & not be good?!?!?! seems to know all there is to know, mine of information.

Billy