A-4 downshift lunge
A-4 downshift lunge I have an A4 in my 1998 Z28. Bought the car with 25K on it, now have 46K on the car. Its done this ever since I bought it. When the car downshifts from 2nd to 1st gear the car jerks forward. At about 30K miles i replaced the u joints and it went away for about. 50 miles and came back. Every other shift in the car is picture perfect. The jerk feels like it comes from the rear. Like someone bumping into the car almost. If I put the car into neutral it does NOT happen. It DOES happen in both D and OD
If you can't find a problem you're most likely not going to be able to fix a problem.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
If you can't find a problem you're most likely not going to be able to fix a problem.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
Thanks.
If you can't find a problem you're most likely not going to be able to fix a problem.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
Sure someone can point to a part and say replace this or that and you might be able to do that, but how does that get done over the internet?
If I say replace the lower control arm bushings and you do it but it doesn't fix the problem and you're out the time and money are you going to be happy with that?
You're probably better off having someone look at it.
Thanks.
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TECH Fanatic
Joined: Nov 2011
Posts: 1,367
Likes: 144
From: Woodstock, GA
I would start by considering the possibilities. Transmission mount .... do you get a vibration? Also you mentioned u-joint replacement in the past cleared it up (for 50 miles). That's a huge clue to me. You should be able to get under it and pry and inspect those things.
I would start by considering the possibilities. Transmission mount .... do you get a vibration? Also you mentioned u-joint replacement in the past cleared it up (for 50 miles). That's a huge clue to me. You should be able to get under it and pry and inspect those things.
TECH Fanatic
Joined: Nov 2011
Posts: 1,367
Likes: 144
From: Woodstock, GA
The only way that I can see that a u-joint would fail so quickly would be installation error. Did you do the replacements? I can't imagine how it would happen, but it's interesting that the problem cleared up right after replacing them. But ..... it could well be the transmission since it's only a downshift from 2 to 1. Every now and then mine will clunk when it's "hunting" (I think that's what it's called) while I'm slowing down immediately after accelerating. It's always done that and I guess that's the nature of the beast.
TECH Junkie
Joined: Dec 2012
Posts: 3,614
Likes: 1,326
From: Iowa
the car jerks forward...or your head jerks forward?
if your head jerks forward (like if you were to tap the brakes) that would be a much different diagnosis than if you said the car lunges forward (which would plant you back in your seat)
if your head jerks forward (like if you were to tap the brakes) that would be a much different diagnosis than if you said the car lunges forward (which would plant you back in your seat)
That's a very interesting discussion piece. It is more like a jerk without a sound while coming to a stop. Literally the second before it stops and shifts into 1. Its the car itself lunging forward. The RPMs don't move at all when it happens.
The only way that I can see that a u-joint would fail so quickly would be installation error. Did you do the replacements? I can't imagine how it would happen, but it's interesting that the problem cleared up right after replacing them. But ..... it could well be the transmission since it's only a downshift from 2 to 1. Every now and then mine will clunk when it's "hunting" (I think that's what it's called) while I'm slowing down immediately after accelerating. It's always done that and I guess that's the nature of the beast.
So you can actually hear a clunk in the rear when this happens. I guess i became so accustomed to it over the years I just didn't notice it anymore. I also double checked and the car definitely jerks slightly forward and clunks in the rear. Just to clarify it does ever so slightly make your head go BACK.
TECH Junkie
Joined: Jun 2008
Posts: 3,202
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From: Nitro Alley
I am just thinking back now... as I almost never see any THM350 units in my shop any more...
I recall two or three revisions to the low/ reverse one-way roller clutch and outer race assembly going from 350 to 700 and to 60E.
-One time the rollers had their diameter increased with slightly larger retention springs.
-Another time the height of the one-way roller clutch was increase to take advantage of the full height of the outer race.
If I recall correctly; the only time I experience problems with these would be when some dumb-**** design trans-brake gets added to a 350/ 700/ 60E.
I have had my guys replace these on every rebuild for the longest time... but are you seeing issues or torque related failures in your shop?
TECH Junkie
Joined: May 2012
Posts: 3,048
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From: Poplarville, MS
I think MaroonMonster is referring to how the low roller clutch outer race will wear the splines in the case and the low roller clutch outer race will twist in the case causing a clunk on down shift.
Is this low roller problem going to happen at 46,000 miles? I don't think so, unless the car has been neutral dropped a few times. I've had that problem with a th350 that I rebuilt for a guy I worked with several years ago. The low roller broke.
I had at least 50 low rollers in buckets because a transmission hard parts supplier needed his building emptied out and let me take whatever I wanted. I looked at every one of those low rollers and they all looked as good as new, was trying to figure out why the one broke. Later I found out the guy had been neutral dropping it.
So this car and all of its major parts have 46,000 miles? If that's true there's more to this story. I have an '02 SS with 54,000 miles.....with a '99 4L60E built from a core that had 250,000 on it because I once converted the car to a six speed and went back to an automatic. It has no problems.
If I had to make a wild guess with what's going on I'd look at the idle on this car. The way it's described put this problem right where the idle transitions happen in the tuning.
I can't go out and drive either of my two because they have high stall converters (which change the feel of coming to as stop) and all the little quirks have long been tuned out, like way back when they were stock.
So what kind of life has this car seen in it's 46,000 miles? I doubt that will be answered. Maybe the transmission needs to be pulled, because now there's a direction to go (although I thinks it's the wrong one).
I had at least 50 low rollers in buckets because a transmission hard parts supplier needed his building emptied out and let me take whatever I wanted. I looked at every one of those low rollers and they all looked as good as new, was trying to figure out why the one broke. Later I found out the guy had been neutral dropping it.
So this car and all of its major parts have 46,000 miles? If that's true there's more to this story. I have an '02 SS with 54,000 miles.....with a '99 4L60E built from a core that had 250,000 on it because I once converted the car to a six speed and went back to an automatic. It has no problems.
If I had to make a wild guess with what's going on I'd look at the idle on this car. The way it's described put this problem right where the idle transitions happen in the tuning.
I can't go out and drive either of my two because they have high stall converters (which change the feel of coming to as stop) and all the little quirks have long been tuned out, like way back when they were stock.
So what kind of life has this car seen in it's 46,000 miles? I doubt that will be answered. Maybe the transmission needs to be pulled, because now there's a direction to go (although I thinks it's the wrong one).