Auto Gearbox 280GE Whinning Issue
Hi Guys.
Have a 1988 2.7L Gwagon 280GE AUTO. Was sitting in a field for 3 years and have spent the last year renovating it. I've been very lucky to find a great mechanic (and this amazing forums) who has gotten the truck running great with a lot of hard work/phone calls. We are in the caribbean. Tough to find a good mechanic.
We are onto the gearbox and going to pull the transmission;
1. There is a whinning noise when we first drive forward off in1st/2nd gear. When it hits 3rd gear it stops whinning. The best way to describe this noise is it sounds like it's going in reverse (this same whinning noise)...
2. It also feels the gears slip sometimes
3. He feels we may be starting to drive in 2nd gear (not starting in 1st at all) and can only hit 40mph max..
Guys is there any electrical components to these transmissions?
We have replaced the kick switch.
Guys any guidance or help is very much appreciated for us as these forums have been great for us..thx guys..Tony
Hello Kman,
Good to hear you are finding your way around the little truck and making progress with its health !
As you know I am not the best when it comes to engineering and mechanicals but I was told once that the auto box is controlled via the vacuum system so might be worth checking you have no blockages or breaks in your vacuum pipes ?
Best of luck,
Neil
It's supposed to start in 2nd. You can force it to start in 1st by selecting it manually or flooring the throttle to make it kick down.
There are no electronics in these transmissions.
Are you sure the whine is not coming from the transfer case?
Once you remove the gearbox sump the filter is right there, it will be obvious.
Maybe a dumb question but are you sure it's in high range?
As Russ mentioned, check the transfer-case lever is in S position for 2-wheel drive, high-range.
I know others have made this mistake, wondering why the engine revs are so high.
While at it, change the oil also in the transfer-case, It should be a GL-4, gear oil, SAE-80W or one of the 75W-80 or 75W-90, but NOT a GL-5 type. (must not mention API GL-5).
... and most importantly, don't forget to grease the 3 prop-shafts (3 grease-points on each: Universal- joints at each end and and extending spline in the middle), and change the diff oil, too. This should be a GL-5 type, Hypoid or EP oil, nominally SAE-90W or one of the 75W-90
(http://www.widman.biz/uploads/Transaxle_oil.pdf)
For the auto-transmission:
if you feel a reaction within a second of moving the auto-transmission lever from P or N to D or R, then the gearbox is likely fine.
But change the oil and filter. It's exactly the same as in any Mercedes car of that vintage (W123, W124 etc) and very simple to do.
Bear in mind that I know next to nothing (that's why I'm always on here asking for help) - but doesn't this sound as though the car has gone into "limp home mode"?
What rpm is it doing at 40mph?
Mark,
It doesn't have a limp home mode.
Oooops
i recently had someone ask me that their g wouldn't go fast, turned out to be brakes binding, had u checked brakes and will it roll freely ?
If it's binding brakes, then Brakes International can supply replacement pistons and seals for the calipers, or complete refurbished calipers, for relatively little. However, I would go for the seals and pistons, if your calipers are in decent cosmetic shape. (The refurbished calipers are nicely galvanised and shiny, but most are heavily pitted from previous rust)
Have you checked all the linkages and vacuum switches for the throttle, as these then connect and control the gearbox? The vacuum affects the quality of shift and the throttle linkages, the shift points. Also, check the kick-down solenoid valve, which will keep a lower gear ratio, if not working properly or stuck.
The brake servo is on the other side of the fire-wall so ensure that you have no vacuum leaks (hissing).
The vacuum lines are made of nylon and quite tough, but the connections are rubber and they deteriorate with age and eventually leak. Ensure that the vacuum system, valves and switches are all checked and renewed if necessary. Then, tighten the throttle linkages- particularly from gearbox to engine - to remove any slack in the cables, as this will affect the shift-points.
The gearbox oil filter is not expensive and is a paper-element type, which is not intended to be washable / re-usable.
if none of this works, then perhaps a visit to a transmission specialist may help, if indeed there is an internal fault in the gearbox. It might be why the car was abandoned in the first place?
The transmission oil filter is encased in a flat metal can, but it is paper inside.
If you intend to flush the oil once or twice, don't worry about the oil in the oil in the torque converter housing, it will mix with the new oil as it gets pump around the gearbox and the small quantity will get diluted out.
The rear wheel brake cylinders will rust, leak and need to be replaced as you've done, but check the front calipers too, as the pistons can stick, if their weather-boots are damaged.
There is a link for the throttle to the top of the engine valve-cover, where it joins a mechanism with a limit switch and vacuum valve. There is also another bowden cable from here that connects to the gearbox.
There should be a lot of information on-line for the Mercedes W123 saloon, which used the same engines and systems as your G-wagen:
there are some diagrams in the above link and some more info here.
It might be worth investing in a mercedes WIS CD set with ECP (about £20 on ebay) as this will give you a lot of the diagrams and part numbers you require. or register here
http://www.service-and-parts.net/dcagportal/DCAGPortal/portal.action
Hi Neil great to hear from you. Hope the xmas/new year went well...
Thx for above as always (interesting)...any direction on were i might find a diagram/layout of vacuum system??
Have manual but nothing there..Also forget to mention we replaced transmission fluid before xmas..
Neil always appreciate the advice/direction and yes the little truck is running well with all your guidance/help/great to drive..last item i feel now is figuring transmission...thx again man..tony