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#1
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Soft & Slow 3rd to 4th Shift - 722.303
With some luck I've found and bought a 2nd W126 300SD, a very good 1984 from Texas without any rust, and have been working through the few neglected issues that came with the car.
Transmission shifts from 1 to 2 and 2 to 3 are quick, firm, and without any flaring after setting the line pressure to 41PSI and modulator vacuum at idle to 9 inches. The shift from 3rd to 4th is however slow and soft. From reading the posts I found in the forum archives, it appears that the B2 piston, its fit in its bore/sleeve, and the piston's link to the band are considered the probable culprits with poor 3rd to 4th shifts. Is the B2 piston and its related parts the primary and likely cause of slow and soft shifts into 4th gear? I'm wondering about this given the fact that all other shifts are very good. It would seem that the B2 band clamping would also occur during other functions in addition to the 3rd to 4th shift. What else could be checked? Any comments will be appreciated very much.
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Respect, protect, and maintain complex systems - whether natural or of German design, to benefit from their full potential. 1982 300SD W126.120 with an OM617.950 from a W116.120 1984 300SD W126.120 with an OM617.951 |
#2
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If you don't have any trouble moving off from a stop your B2 is OK, unless it really bangs on a 4-3 downshift; then the internal seal is suspect.
Probably you just need a "shift kit," exhaustively discussed previously. Only add the spring which corrects your particular issue--3-4 flare, in this case--not the entire kit.
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James Marriott 2003 Buick Regal 1983 300D (228k, frau Auto) 1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000) www.engineeringworks.biz 1987 300SDL junker 170k 1982 300SD junker, 265k |
#3
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bump...
Thanks Jim, but I'd like to hear some additional comments in addition to yours.
__________________
Respect, protect, and maintain complex systems - whether natural or of German design, to benefit from their full potential. 1982 300SD W126.120 with an OM617.950 from a W116.120 1984 300SD W126.120 with an OM617.951 |
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