| AndySimms | -- 11-22-2010 @ 3:15 AM |
|
h*llo guys I have a question about an early Ford V8 truck. In reverse the truck shutdders and binds up with a bit of a 'clunk' noise ... it feels like the back wheels just ran into a kerb stone. I suspected the drive shaft/ U-joints so I slid in under for a look. When I grab the drive shaft - on the end near the gear box - there is a bit of movement there in the shaft/u-joint area, but not too much. I guess my question is - is any movement in the shaft and u-joint acceptable? or would this slight movement be causing my problems? The truck drives 100% in forward gears and this shuddering only happens in reverse. Look forward to your input and thoughts on this. thank you Andy
|
|
| TomO | -- 11-22-2010 @ 7:34 AM |
|
Andy, you should not have any movement within the U-joint, except for the rotation of the arms in the bearings. Tom
|
|
| supereal | -- 11-22-2010 @ 8:39 AM |
|
U-joints have slack for two reasons: A failing bearing cup in the u-joint, itself, or a loose spline from wear or damage. There is always the possibility that the ring and pinion may be involved, but if you see slack in the drive line, that is likely not the cause.
|
|
| AndySimms | -- 11-22-2010 @ 8:51 AM |
|
Thanks guys, I thought there shoudlnt be any slack in there - is there a sopecific reason though why this would show up as a shudder in reverse gear only and not in forward drive? Supereal you wrote "but if you see slack in the drive line, that is likely not the cause" .... did you mean to say "that is likely the cause" thanks again Andy
|
|
| supereal | -- 11-22-2010 @ 10:12 AM |
|
Yeah, Andy. The intent was to say that if the driveline (shaft and u-joints) don't show slack, then the differential gears may be at fault. Shuddering in reverse can also be caused by loose or worn motor mounts and/or springs when the driveline is turning in the opposite direction during reverse, putting a 180 degree different stress on the components.
|
|
| TomO | -- 11-23-2010 @ 8:25 AM |
|
U-joints usually give problems in reverse before they show up in the forward motion because the wear pattern was formed in the forward direction and makes the bearing surfaces sort of egg shaped. When you back up, the arm moves out of the egg shaped portion into the original rounded portion of the bearing surface and has a tendency to move in and out of the egg shaped portion. I hope that I made myself clear. It is difficult to explain without a drawing. Tom
|
|
| carcrazy | -- 11-23-2010 @ 12:56 PM |
|
If the rear shock links are loose the vehicle will shudder in reverse.
|
|
| AndySimms | -- 11-24-2010 @ 8:56 AM |
|
Guys, Superreal and everyone thank you all for this great info. Tom thanks falso for the added detail of why shuddering would show up in reverse first - thats very interesting and something for me to think about. Andy
|
|
| jerry.grayson | -- 11-24-2010 @ 12:52 PM |
|
You did not mention what year your truck was and wheather it is a pickup or 1 1/2 ton big truck. Shuddering in reverse in trucks and cars with closed drive lines is most of the time either clutch problems or missing or loose engine stay rods.
|
|
| AndySimms | -- 11-25-2010 @ 2:53 AM |
|
Hi Thanks for reply - the truck is a 1944, 3-ton 4x2 flatbed truck. If it was clutch problem would I not be experiencing the shudder when in forward gear also? Many thanks Andy
|
|
| supereal | -- 11-25-2010 @ 10:07 AM |
|
It is probably safe to assume that the u-joints on your big truck need replacement, as the grease in the cups is likely hard, if there is any left. Open drive line joints are subjected to the elements, and their life, even today, tends to be fairly short. Be sure that the grease fittings on the spline parts are open and will accept grease until it comes out at the end. The motor mounts may also be atrophied, and in need of change. Another thing to remember is to mark the shafts before you remove them to maintain the original balance when reassembled. After 66 years, there is a lot to do.
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=2215 |