PS Magazine - NOVEMBER 1986
PS, The Preventative Maintenance Monthly
ISSUE 408
NOVEMBER 1986
'I±
i.
,
±
²
1±
Some drivErs cut coMers when they drive their deUce-and-a-hAfs .±± aNd eND Up
wiTh sPrag clutch "wind²uP³´
WInd²uP results when a driver:
µ Lets thE truck co¶st backward with the transmission In a Fr·aRd gear, oR ro¸¸
Frward in reverse gear³
¹ ºRIves away »om a stoP In second
geaR³
¹ ¼hi½s »om reverse to ¾rst gear or
»om a Frward gear to reverse without
m¿ng a comPÀete stop³
³
you 're one of the coMEr²cutÁers and
if your tÂck h¶s an automatic sprag
clutch, You'Àl gEt wind²UÃor worseÄ
bust a proP sha½, »ont axle or transÅr.
ÆoUr trÇck must be In the right gear
In late model Trcks,
the spRg
·
uniT's cont±olled
by a leve± iN The cab
Fr The direction you're ÈGÉeVen when you're co¶sting. Êf it's not, tHe
sprag cÀutch ÀocKs in
Ë
the »ont drive³ Ìhen Íhe »ont²wheÎÀ
a
reaR²wheEl Ïrives
batÁÀe Fr control³
Ìhe sPrag's wedges arE Ðositioned between the Inner and oUter race oN the »ont
sha½ of the transÅrÑ Ònder norm¶À conditions, the outer race (»om the tRansÓ
mission)
tr
sÀower th¶n The InneR Ôace to the »ont wheeÀs. Êf the
Õ
rear wheEÀs lose
18
NOV 86
tRaction the oUteR race st¶Rts tURning
Öster ×aN the ØNneR Ùace. Ìh¶t engages
tHe spR¶g wedges, Úd tRansÅRs the ÏrivÛ
iNg poweR to the »ont wheeÀs.
WHen THe re¶R whee¸s rÜgaØN tRaction,
tÝe sprag weÏges shoUÀd re¸ease. Êf they
don't, yoU have a c¶se of wInÏÞUp. ßhe
tRÇck's »ont wheeÀs boUnce yoU AÀ over
TÝe Road .
.. it's hard steÎrIng stràght. .
.
·
áe âcã jäps oUt of går .
.. oR it's hæd
sHçèØng.
Ìreat wØnd²up ÀIke so:
Êf yoU coasted backward In a Frward
gear, ÏrIve Frward the s¶me distance
you co¶sté backward.
´
êt dOn't reÀåse ëe spìg wíges,
Shf
the tranmissIoN iNto reverse.
T turNiNg the wheel iN bth
de-
±IoNs²
µ
should
T
BackarD Eily,
But Not fRwarD at
Al¶
®
@
jacã a îoNt wHïe¸ oð áe ñ. ßòng
the weight oð the ·hee¸ m¶y be eNoógH
·
cuRe tÝe wIndÞUp. Be c¶reôl, õo! Ìhe
wInd²Up can Àet go withoUt wöng.
WØtÝ the whee¸ jacãeÏ Up, test the
sprag cÀUtch this way:
³ow, shIF iNto ´rst gear² µHe
w¶eel sHoulD turN ·rward, But Not
BacKwarD¸
NOV 86
19
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