Shudder on take off
Thread Starter
|
Mountain Pass
Joined: Feb 2016
Posts: 205
Likes: 13
From: Southington CT
Shudder on take off
On my 79 F 250 with 400 and NP435 it sometimes shudders when taking off in 2nd gear. I can't tell where it's coming from but it seems much worse when the motor is hot. When driving for the first 20 minutes it takes off smooth. Was thinking maybe the flywheel warps with heat. Also, I took a video with my kids Gopro and I see a lot of flex from the rear springs. (the clanking noise in the video I believe is my tailgate) Anyone ever have this problem?
https://www.youtube.com/watch?v=VIBI...ature=youtu.be
https://www.youtube.com/watch?v=VIBI...ature=youtu.be
Postmaster
Joined: Nov 2011
Posts: 2,553
Likes: 10
Usually shudder is caused by an uneven flywheel or clutch problem like crack in the pressure plate. If it already has tendency to shudder launch technique can help reduce it. Taller gearing with large tire diameter may aggravate it as well.
The oscillating axle is not typical. Does it happen when the clutch is shuddering? They could well be related axle the axle winds up when the clutch bites and unwinds when it slips.
As far as getting worse with heat goes, it may be the friction material biting harder when warm, or the flywheel distorting as you suggest. Or something is binding up as the crankshaft grows.
The best "fix" is close visual inspection of all working parts of the clutch including the pilot bearing and release levers. Also get the flywheel inspected for cracks and re-surfaced by a good machinist. Yes... this means dropping the transmission. Also a new clutch. Sorry.
It also would not hurt to check u joints and the rear differential pinion for slop. Also make sure the bolts that connect the end of the axle to the hub are tight.
The oscillating axle is not typical. Does it happen when the clutch is shuddering? They could well be related axle the axle winds up when the clutch bites and unwinds when it slips.
As far as getting worse with heat goes, it may be the friction material biting harder when warm, or the flywheel distorting as you suggest. Or something is binding up as the crankshaft grows.
The best "fix" is close visual inspection of all working parts of the clutch including the pilot bearing and release levers. Also get the flywheel inspected for cracks and re-surfaced by a good machinist. Yes... this means dropping the transmission. Also a new clutch. Sorry.
It also would not hurt to check u joints and the rear differential pinion for slop. Also make sure the bolts that connect the end of the axle to the hub are tight.
Thread Starter
|
Mountain Pass
Joined: Feb 2016
Posts: 205
Likes: 13
From: Southington CT
Thanks for the reply. In the video it really didn't shudder too bad. What I find so odd is how smooth it takes off when cold. Either way I have to address the leaf spring flex issue.
Moderator & parts slinger
Joined: Feb 2007
Posts: 50,188
Likes: 5,792
From: S/W Missouri, Polk county
Could mean you just need to adjust the clutch, or that shudder could be caused by oil being on your clutch face. Meaning you have a possible leak..rear main?
In the video the axle wrap looks to be due to stacked blocks back there.
In the video the axle wrap looks to be due to stacked blocks back there.
Thread Starter
|
Mountain Pass
Joined: Feb 2016
Posts: 205
Likes: 13
From: Southington CT
No stacked blocks, just the factory block and 4" lift add a leaf. Starting to think it something in how the motor runs when hot. It is worse when I restart after leaving a restaurant or similar. It's fine when I fire up and drive off cold. I'm willing to deal with it for now as I don't have the time to yank trans. I will look into changing rear springs though.
Thread
Thread Starter
Forum
Replies
Last Post
MustangGT221
Clutch, Transmission, Differential, Axle & Transfer Case
1
Jan 1, 2005 09:13 AM
tville87
Clutch, Transmission, Differential, Axle & Transfer Case
6
Dec 26, 2002 12:14 PM
