Car (South Africa) - - TECH -

My dad’s work re­quires a lot of driv­ing, whereas my mom drives ex­clu­sively round town. On the odd oc­ca­sion that my fa­ther drives my mom’s car, he com­plains about how the gear­box has “be­come lazy”, which he at­tributes to all the stop/start driv­ing.

I have only a ba­sic un­der­stand­ing of how gear­boxes work, but I would think it’s a fairly com­plex as­sem­bly with pre­cise tol­er­ances and is there­fore pretty set in how it op­er­ates. Is it pos­si­ble for a driv­ing style to, over time, change the char­ac­ter­is­tics of a gear­box? Or is this “lazi­ness” just due to the com­par­i­son be­tween the per­for­mance of the man­ual trans­mis­sions of his SUV and her small hatch­back? DAMIAN AUSTIN Wit­bank

Ob­vi­ously, a man­ual trans­mis­sion can only be as “lazy” as its user. There is some truth when it comes to au­to­matic trans­mis­sions, though. The shift points of an au­to­matic trans­mis­sion de­pend on the en­gine speed, ve­hi­cle speed and throt­tle po­si­tion. In the en­try-level seg­ment, this cal­i­bra­tion is nor­mally xed, with another xed map for those trans­mis­sions equipped with a sport mode, where the shift points are moved higher up the en­gine rev range, the kick-down func­tion en­gaged ear­lier and the throt­tle cal­i­bra­tion more ag­gres­sive.

In higher-end ve­hi­cles, these cal­i­bra­tion pa­ram­e­ters some­times al­low for a de­gree of learn­ing to al­ter the be­hav­iour slightly in a range be­tween the xed val­ues to suit the driv­ing style of the user. In this case, the trans­mis­sion can ap­pear “lazy” un­til new val­ues are learned, which hap­pens fairly quickly. Your no­tion of com­par­ing the per­for­mance dif­fer­ence of the two ve­hi­cles might just be the cor­rect con­clu­sion.

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