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These transmissions need to quit their whining

Thursday, July 31, 2014 - 07:00
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I don’t know how many times I’ve been driving down the road and a Honda Odyssey van or an Acura MDX will pass by and it sounds like it has a supercharger in it. Did this thing just get hopped up at the local speed shop? I think we can all agree that the answer is no. It’s the transmission, ready for a rebuild at the local transmission shop.

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Here at H&A Transmissions in Rancho Cucamonga, Calif., Honda and Acura transmissions are our specialty. That’s all we do and we have plenty to say on the subject of whining. We field multiple calls for whining symptoms every day while taking in new orders for our remanufactured transmissions from independent repair shops, transmission specialty shops and dealers all over the country. There are many different combinations of whining symptoms that will point the finger right at the transmission. Some of the more common whining symptoms you might hear from a customer who brought a Honda or Acura vehicle into your shop are whining in 1st and 2nd gear, whining in park and neutral, whining at 40 mph and above or just simply whining all the time while driving. Generally the noise will be high pitched, from slight to downright loud. Honda and Acura automatic transmissions do not use planetary gear sets, they use single sets of input and output gears for 1st through 5th gear and reverse just like a manual transmission, which can make some big noise. So what is all this whining about?

This whining that you are hearing more than likely is gear noise caused by worn out bearing bores in the aluminum cases. The most common style of unit with noise issues is the 5-speed automatic three shaft unit that fits V-6 engine applications including the 2002-’06 Honda Odyssey, the 2003-’07 Honda Accord, the 2003-’05 Honda Pilot, the 2001-’02 Acura MDX, the 2000-’06 Acura TL and the 2001-’03 Acura CL. There are three pieces that make up a set of cases (or housings) for this three shaft unit. You have the main case, which is in the center of the trans; the bell case (or front case/bell housing), which sits at the front of the trans; and the end cap (or end cover), which sits at the rear of the trans (Figure 1). The bearing bores you find worn out are in the main case and the bell case and are what we will focus on.

The main case houses three large ball-type roller bearings that are the rear supports for the main shaft, the countershaft and the secondary shaft (Figure 2). These bearings take quite a beating from the constant load changing through the shafts via the clutch packs and gear sets as the vehicle makes its way down the road through daily stop and go traffic. The aluminum cases are just too soft and not strong enough to handle that thrust load over time and they begin to wear out. You will find the majority of the wear in the main shaft and in the countershaft bearing bores as they are your main input and output shafts and take most of the load. We currently do not see many issues with the secondary shaft bearing bore, but it is advised to be inspected along with the other bores.

The bell case houses the large countershaft non-ball type roller bearing, which is the front support for the countershaft and the other culprit for heavy bore wear. All of the output power flow is travelling through that countershaft to turn the ring gear and put power to the wheels to propel the weight of the vehicle.  You will also find a smaller ball-type roller bearing, which is the front support for the secondary shaft. We do not see significant wear in this bore and find this to not be an issue but should always be checked as well (Figure 3).

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