Merctrans
06-17-2017 | 03:43 PM
#4
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Joined: Oct 2009
Posts: 48
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From: bellingham,wash
Merctrans
Hi, Kirk at KC Marine here. Just so everybody knows. Any given a,b,c,d or e MercTrans internal components are interchangeable in any given case. Given the age of these transmissions, I see a constant mix of internal component changes; as "somebody" has likely been inside before, and mixed parts. So, in reality the tranny tag (abcde) means nothing until you get inside and see. The problem arises in some design changes to the input and output shafts. Unless the proper components are matched, it spells disaster. My website has dimensional drawings of the different shafts.
The "major" issue is the oil pump key size. The a,b and some c (if original), have a very small support key, and have made hundreds of higher horsepower, and "loaded" transmissions a casualty ( oil pump gears break).....It is important to have the larger keyed pump gear and input shaft. In relation to this is often the fact that, upon repower the crankshaft support bushing is left out of the end of the engine crankshaft. The mistaken assumption is that the flex plate supports the input shaft. The extension on the input shaft "must" be supported by the additional bushing. The original bushing is nla. Get a B50-HD bushing and machine the OD to 1.707"....It fits chev perfectly
The "major" issue is the oil pump key size. The a,b and some c (if original), have a very small support key, and have made hundreds of higher horsepower, and "loaded" transmissions a casualty ( oil pump gears break).....It is important to have the larger keyed pump gear and input shaft. In relation to this is often the fact that, upon repower the crankshaft support bushing is left out of the end of the engine crankshaft. The mistaken assumption is that the flex plate supports the input shaft. The extension on the input shaft "must" be supported by the additional bushing. The original bushing is nla. Get a B50-HD bushing and machine the OD to 1.707"....It fits chev perfectly
08-11-2023 | 11:08 AM
#5
Registered
Joined: Aug 2023
Posts: 1
Likes: 0
Merctrans A,B,C,D or E...
Hi, Kirk at KC Marine here. Just so everybody knows. Any given a,b,c,d or e MercTrans internal components are interchangeable in any given case. Given the age of these transmissions, I see a constant mix of internal component changes; as "somebody" has likely been inside before, and mixed parts. So, in reality the tranny tag (abcde) means nothing until you get inside and see. The problem arises in some design changes to the input and output shafts. Unless the proper components are matched, it spells disaster. My website has dimensional drawings of the different shafts.
The "major" issue is the oil pump key size. The a,b and some c (if original), have a very small support key, and have made hundreds of higher horsepower, and "loaded" transmissions a casualty ( oil pump gears break).....It is important to have the larger keyed pump gear and input shaft. In relation to this is often the fact that, upon repower the crankshaft support bushing is left out of the end of the engine crankshaft. The mistaken assumption is that the flex plate supports the input shaft. The extension on the input shaft "must" be supported by the additional bushing. The original bushing is nla. Get a B50-HD bushing and machine the OD to 1.707"....It fits chev perfectly
The "major" issue is the oil pump key size. The a,b and some c (if original), have a very small support key, and have made hundreds of higher horsepower, and "loaded" transmissions a casualty ( oil pump gears break).....It is important to have the larger keyed pump gear and input shaft. In relation to this is often the fact that, upon repower the crankshaft support bushing is left out of the end of the engine crankshaft. The mistaken assumption is that the flex plate supports the input shaft. The extension on the input shaft "must" be supported by the additional bushing. The original bushing is nla. Get a B50-HD bushing and machine the OD to 1.707"....It fits chev perfectly
