Dodge Sprinter 2006 Manual page 1910

21 - 172 AUTOMA TIC TRANSMISSION NAG1 - SERVICE INFORMA TION
dir ect ly, wh ich m ea n s t h a t t h e solen oids m u st h a ve
ver y h igh ou t pu t s t o close t h e va lves a ga in st t h e siz-
a ble flow a r ea s a n d lin e pr essu r es fou n d in cu r r en t
t r a n sm ission s. F a st r espon se t im e is a lso n ecessa r y
t o en su r e a ccu r a t e con t r ol of t h e t r a n sm ission .
Th e st r en gt h of t h e m a gn et ic field is t h e pr im a r y
for ce t h a t det er m in es t h e speed of oper a t ion in a pa r-
t icu la r solen oid design . A st r on ger m a gn et ic field will
ca u se t h e plu n ger t o m ove a t a gr ea t er speed t h a n a
wea ker on e. Th er e a r e ba sica lly t wo wa ys t o in cr ea se
t h e for ce of t h e m a gn et ic field:
1. In cr ea se t h e a m ou n t of cu r r en t a pplied t o t h e
coil or
2. In cr ea se t h e n u m ber of t u r n s of wir e in t h e coil.
Th e m ost com m on pr a ct ice is t o in cr ea se t h e n u m -
ber of t u r n s by u sin g t h in wir e t h a t ca n com plet ely
fill t h e a va ila ble spa ce wit h in t h e solen oid h ou sin g.
Th e st r en gt h of t h e spr in g a n d t h e len gt h of t h e
plu n ger a lso con t r ibu t e t o t h e r espon se speed possi-
ble by a pa r t icu la r solen oid design .
A solen oid ca n a lso be descr ibed by t h e m et h od by
wh ich it is con t r olled. Som e of t h e possibilit ies
in clu de va r ia ble for ce, pu lse-widt h m odu la t ed, con -
st a n t ON, or du t y cycle. Th e va r ia ble for ce a n d pu lse-
widt h m odu la t ed ver sion s u t ilize sim ila r m et h ods t o
con t r ol t h e cu r r en t flow t h r ou gh t h e solen oid t o posi-
t ion t h e solen oid plu n ger a t a desir ed posit ion som e-
wh er e bet ween fu ll ON a n d fu ll OF F. Th e con st a n t
ON a n d du t y cycled ver sion s con t r ol t h e volt a ge
a cr oss t h e solen oid t o a llow eit h er fu ll flow or n o flow
t h r ou gh t h e solen oid's va lve.
UPSHIFT / DOWNSHIFT SOLENOID VALVES
Fig. 229 Upshift/Downshift Solenoid Valves
1 - UPSHIFT/DOWNSHIFT SOLENOID VALVE
2 - CONTACT SPRING
3 - CONDUCTOR TRACK
4 - O-RING
5 - VALVE HOUSING OF SHIFT PLATE
6 - O-RING
7 - CONDUCTOR TRACK
8 - CONTACT SPRING
Th e solen oid va lves (1) for u psh ift s a n d down sh ift s
(F ig. 229) a r e loca t ed in t h e sh ell of t h e elect r ic con -
t r ol u n it a n d pr essed a ga in st t h e sh ift pla t e wit h a
spr in g.
Th e solen oid va lves (1) in it ia t e t h e u psh ift a n d
down sh ift pr ocedu r es in t h e sh ift pla t e.
Th e solen oid va lves (1) a r e sea led off fr om t h e
va lve h ou sin g of t h e sh ift pla t e (5) by t wo O-r in gs (4,
6). Th e con t a ct spr in gs (8) a t t h e solen oid va lve
en ga ge in a slot in t h e con du ct or t r a cks (7). Th e for ce
of t h e con t a ct spr in g (8) en su r es sa fe con t a ct s.
VA