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Re: Tranny knock scenario-CMyles Posted by CMyles [Email]  (#1126) [Profile/Gallery]
(more from CMyles) on Sun, 31 Aug 2008 11:47:14
In Reply to: Tranny knock scenario-CMyles, white65, Sat, 30 Aug 2008 21:06:59 Members do not see ads below this line. - Help Keep This Site Online - Signup |
white65,
As Swedecar says, it could be the transfer case chains slapping if the tensioner block is upside down, or for some reason just failing to pump up. You'll need to pull the transaxle front cover to correct or check for that but if it's a "Known good" transaxle and no one has been in there than it should be installed correctly. You should pop off the upper chainwheel cover and pour about half a quart of oil in there and then drain the same amount through the drain plug (or suck it out the filler hole).
How long was this transaxle sitting? A gear or bearing can develop rust and the slag that gets in the bearings can solidify if undisturbed for a long time and either can cause a knock once the parts start spinning again.
How was the thrust figure on the crankshaft? You say that the engine was rebuilt and that the knock comes from the front end but an engine with excessive axial motion of the crankshaft due to bad (or miss fitted) thrust bearings will knock when the clutch is engaged and stop knocking when the clutch pedal is pressed down.
If adding oil to the transfer case and letting it run a bit doesn't stop the noise then remove the transaxle front cover and see if the tensioner is pumped up and doing it's job. If the tensioner is working OK then remove the clutch shaft, clamp some vice grips on the input shaft nut at the lower chainwheel and (in neutral) spin the transaxle while feeling for knocking. If you feel the knock then take the chains and chainwheels off and inspect the chains for tight links (very rare) and the upper chainwheel bearing for problems. If no problems with those then put the lower chainwheel back on the input shaft and spin it and feel for any knocking in the gear train. If you can feel knocking or catching there then you've localized the problem to the geartrain in the transaxle and fixing it will require rebuilding. If you find no problems there then you should remove the clutch and inspect it carefully, especially the throw out bearing, and check the axial motion of the crankshaft with a lever and a dial indicator.
You could go through the clutch and check the crankshaft play first and then open up the transaxle front end if needed, whatever seems easiest for you, the problem is about equally likely to be in any of those locations. Good luck
posted by 198.233....
, Sun, 31 Aug 2008 11:47:14 <-- Viewing This Message, Sun, 31 Aug 2008 09:03:52
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