auto box problems
can anybody tell me why my auto box not change up smoothly like the one in my c class merc.thanks
there are alot of vaccum lines which control the time at which you change up ,speed load throtle position ,check if one of these is blocked or has become diconnected to start with.
Besides vacuum hoses, there is another more common problem causing late upshifts or downhifts, this can be the g/box modulator, its self. Mounted on the off-side of the g/box, towards the rear.
It can be easily traced, since it has a singular vacuum pipe feeding the unit. To force an upshift temporarily, at the point upshift should occur, lift foot off acclereator, momentarily, and resume position to original place. This should allow the gear to shift up, over riding the modulator to upshift.
Regards,
Can I add my twopence worth?
Lately been having a problem too with my autobox ('83 280ge). Now it seems you have to rev the engine alot to get the vehicle to move anywhere where as before it moved off with a little encouragement.
Where do I go looking to fix this one?
Thanking you in anticipation.
Regards,
Mike
Hi Mike do the gears select in the correct slots at the base of the gear lever? do you have the same problem in reverse? have you checked the oil level "See recent thread from Rakesh to Huss on how to do this" is the oil clean? or does it smell burnt? rgds Peter
Hi Fixwin,
Forward and reverse are the same. Before when you put it into forward and tipped the accelerator away we go and the same in reverse. Now if it was a manual gearbox I would describe it as the clutch slipping (all revved up and nowhere to go). In this auto box now you have to accelerate hard to get a reaction.
Will try the oil levels tomorrow just in case but they were OK 2 weeks ago.
Thanks for the help.
Regards,
Mike
mike, is it only just when you are moving it about in your drive etc? mines been like that lately, but it hasnt been getting used, i actually think it could be the brakes sticking on a bit as when i get it 100 yards down the street it is absolutley fine, and performs well as usual. if it is used daily ish it is fine, but if left for a couple of weeks i have the issue back - so therefore i dont see it as an issue!!!!!!!!
So far as you mention it the only times I have noticed it is in the yard at home. But saying that the brakes don't feel like they are sticking on.
If I get a chance tomorrow will free spin the wheels to check.
Thanks for the suggestion.
Regards,
Mike
Hi Mike a silly question!! is the transfer box lever set in the two wheel drive high range position ?
YES, what, am I missing something glaringly obvious?
It was OK before in 2wd.
Regards,
Mike
Hi Mike no.... but when you have it in 4 WD or low range you have to rev it harder......
Phew, thank heavens for that. Still didn't get a chance to have another look at it yet, hopefully tomorrow.
Regards,
Mike
Here we go again,
Back to the same problem. I had it out on the forest trails yesterday. Got there, took it off the trailer and away up the road with the rest of them.
At first I thought I left the handbrake on it was that bad. All reved up and going very slow with the 'box in high 4wd. The brakes or diff's are not the issue as all have been stripped bled reassembled and tested and are now all OK.
Thinking I was about to have a lousy day arrived at the first section and selected low 4wd, much to my surprise away it went like something possessed all day long.
At the end of the day and back on the hard stuff, into high 2wd to try that and same as before, all reved up and nowhere to go.
Now, where do I go looking to fix this?
Low box fine/great.
High box performs like clutch slipping in a manual gearbox.
Any and all help graciously received.
Regards,
Mike
hi Mike what is it like in low 2wd...
Hi fixwin,
Thanks for coming back on this one as I was beginning to think I was all alone.
My understanding was that positions S = 2wd high, SA = 4wd high, N = neutral and GA = 4wd low .
Positions S and SA give the same response = all reved up and not going too far too fast.
Position GA = good pickup and kickdown and low top speed as you would expect.
If its something wrong in the gearbox itself should this not show itself in both high and low boxes?
Personally and without much knowledge my thoughts are that it is a problem with the high ratio in the transfer box. I may be way off the mark on this one and desperately need help/advise to sort it.
Regards,
Mike
Hi Mike it could be the clutch bands slipping in the auto G'box... dip the G'box and smell the oil... if it has a burnt smell that is because it has overheated... if it is brown coloured it has overheated.. you say is revs out in High 2wd and High 4wd that would point towards worn clutch friction bands in the G' box. more torque is required to drive the higher ratio. I thought you might have had a broken rear axle halfshaft but your diagnosis of high 2 and 4wd points towards the G'box.......
Well now fixwin, don't keep me in suspense, is it fixable, repairable or does it come down to being cheaper to replace the gearbox?
If repairable whats involved and is it a DIY job or professional one?
Will the gearbox out of a car with the same engine do?
Regards,
Mike
Hi Mike repair is with specialist auto G'box workshop only..exchange boxes from GB are around GBP 600 plus shipping...I have a "removed working" G wagen box here you can have make an offer on and you can collect it anytime....I would like you to try it in 2wd low range to help me diagnose the problem... before you resort to another G' box.......
Hi Fixwin,
This weekend I changed the ATF in the gearbox. It smelled just like the new stuff. Although when I checked the dipstick the level shown indicated a mark about 3" above the max.mark.
Disconnected all the pipes and dropped the pan, drained and changed the oil. Replaced 5lts approx.
Ran it for 5 minutes, then went for a drive. Seems better and there seems to be better pickup, maybe its my imagination. Will try it again during the week.
Off now to fix more little problems. These forest trails really seem to bring all these little things to the fore.
Regards,
Mike
Hi All,
First I am not that technically gifted – so please use simple words!
I have noticed the last few days that when I go to accelerate and press the accelerator the rev’s are there, but the gears don’t deliver the power smoothly, the best way I can describe it is;
Pedal down, rev’s, small power, gear select, then what I would say standard power, then a real ‘clunk’ as it selects the next gear. ‘Kick down’ is again very much the same thing, except the power is not there in its usual response and is rather ‘hesitant’. Apologies for the non technical explanation fellow members, but that’s the best way I can put things!
Driving style would be on the ‘more aggressive than passive’ side and when things allow will not hang around. On some occasions I will use the manual capability to slow/speed up the truck, but not on a regular basis as I have been told that this gear box is not like the more modern Mercs (tip left and right) and should refrain for using the gear selector and leave it in drive.
I have a 2001 G500 V8 463, with 50K on the clock and has FMBSH, all MB parts. Could it be time for a new clutch?
Many thanks
Spider1V
Sorry can't remember if you've done this before or not, but resetting the learning "brain" of the transmission can do wonders to shifting:
http://www.pointedthree.com/disc/forums/showthread.php?tid=8269&start=1&...
Sorry can't remember if you've done this before or not, but resetting the learning "brain" of the transmission can do wonders to shifting:
http://www.pointedthree.com/disc/forums/showthread.php?tid=8269&start=1&highlight=transmission+reset&highlightmode=1
Apologies for the delay - have been out of the country. Now I am back, have done that, but she still seems to be doing the same.........
I should be down at the Clavering do (so far so good) so I can get one of the 'professionals' to take a 'lookey see'
But many thanks for the advice
Spider1V
Yeah hope someone brings along a dipstick so you can measure the level, as they're very sensitive to the correct fluid level.
Also this post may help with the diagnosis, from the US forum, as there are more 500's there than here, hence more experience with their problems:
http://www.pointedthree.com/disc/forums/showthread.php?tid=10249&posts=8 (scroll to the lower half of the page, to a post by DUTCH on oil seeping into the electronic connector).
Yeah hope someone brings along a dipstick so you can measure the level, as they're very sensitive to the correct fluid level.
Also this post may help with the diagnosis, from the US forum, as there are more 500's there than here, hence more experience with their problems:
http://www.pointedthree.com/disc/forums/showthread.php?tid=10249&posts=8 (scroll to the lower half of the page, to a post by DUTCH on oil seeping into the electronic connector).
Thanks for this, read through and certainly the 'hold gear' situation is the same, but its as if the power is lost somewhere.
Foot down revs go up, but not much power, and will only go 'clunk' if I dip the accelerator, hen we get the power.
I did speak to a V8 mate of mine and he suugested maybe a misfiring cylinder??? I have noticed that when in neutral, I rev the car to about 4K and then we get a misfire, not sure if thats the engine protection system, but on all the other V8 Mercs one has owned you could get smoothly up to about 6K before the same would happen.
She is due a service in about 2K miles, should I hold on, or could I be doing damage?
Spider1V
I know you're looking more at the transmission for problems, but we had the "hold down in 1st" syndrome on the 500 a couple of times, and the smart dealer in Dubai changed the crank position sensor (if I remember right)...
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