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DesertStar
Expert
Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
| Hard shifting 280ge automatic transmission
I just got my G back from the shop today for which had the tranny fluid,filter and a replacement vacuum valve(shift valve) done.
The valve was bad which I assume was the cause of my extremely late 3-4 upshift at 52 mph. Now that I got my G back it shifts really hard on the 3-4 upshift...hard like a "shift kit" for towing. It just seems harsh. Since this is the only G I have driven, I must ask if this is normal ? If not what would be possible cause or fix ? I am a little worried it may be too hard for the rearend.
I also find that since the shifts are controlled mechanically vis the throttle rods (versus vaccuum lines on diesels) that upshifts can be made "premature" siomewhat on demand by easing up on the throttle.
Lastly, this may fall into the "get used to it" department....it is really annoying traveling in town going from one stop light to the next and as I slow down for the next light I get the hard upshift when I want to slow down. Whats up with that ?
Any comments or suggestions are welcome.
Mike |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: Hard shifting 280ge automatic transmission
Mike, if the transmission is set up like the 123 or 126 automatics the vacuum modulator is adjustable. On those transmissions the modulator is often a green color plastic thing pluged into the side of the unit. There is a cap on the end that can be pryed off and under it is a metal adjuster locked into recesses in the modulator end. If you pull the adjuster out slightly and turn it counter-clockwise so it lines up with the next set of recesses and push it in there it should soften the shifting. In my experiance one click of adjustment is all it takes. Clockwise is harder. Try one to the left, put the cap back on and test drive it. This suggestion may of course not relate to the gas G setup but if it has this kind of modulator it is an easy fix. I hope this idea works for you.
-Dai
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DesertStar
Expert
Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
| RE: Hard shifting 280ge automatic transmission
Thanks Dai, I will give it a go, once I make sure all my control pressure rods are proper length and adjusted. I hope that is it....fingers will be crossed.
mike |
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DesertStar
Expert
Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
| RE: Hard shifting 280ge automatic transmission
Followup...that was easy. I adjusted the pressure rod, that which connects to the throttle linkage to specs and played around with the modulator as you said (Dai) and now have a smooth shifting tranny.
Mike |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: Hard shifting 280ge automatic transmission
Excellent. Good to know they are set up to be adjustable on those too.
-Dai |
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