Drive train problem

Gargoyle

Gargoyle

New Member
Mar 13, 2006
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Portland, Oregon
I was wondering if any one has any suggestions:


The problem I am having is that after replacing my auto trans in my turbo car I have a very irritating thump in my drive train on initial take off. I replaced the trans because the old one was shot. The replacement is not new but looked alot better and I no longer have the morning sickness problems of it not wanting to shift out of first until it is warm.

When I replaced the trans I also changed the carrier bearing because the old one was completely worn. The replacement bearing I got from Toyota. None of the u-joints on the drive shaft were bound and there isn't any play in them either.

Yesterday I marked the two piece back half of the drive shaft to see if the rubber is holding but I don't think that is the problem either because the ends are still lined up. The diff doesn't appear to have any play in it either.

I did not have this issue with the old trans but can't think of a reason that the trans would have this problem only on take off. If I just let the car roll without giving it gas to a speed of 5-10 mph it wont thump and I can drive it fine. As long as I don't come to a complete stop I don't have the problem either.

If anyone has any useful ideas I would be appreciative. Also, I know I have seen threads on someone supplying one piece drive lines but can't seem to find it. I am thinking of going this route to make sure it is not the drive line but I not having any luck on the searches.

Thank you in advance for any help.
Brian
 
Gargoyle

Gargoyle

New Member
Mar 13, 2006
159
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Portland, Oregon
The "thump", if I had to guess.....feels like it is in the area of the carrier bearing. It is deffinately behind me....I think. When the thumping is happening you can actually see the shifter bounce kinda forward and back.

I checked the trans mount and it is tight.

Yes, the problem is a thump SINCE the swap of the tranny. It is quite possible/likely that it is something I did to myself but I can't figure it out.

Also searched some more and if I can't find a supplier on here I will probably take it to a local drive line shop and see what they can do as for as the one piece.

Brian
 
M

mkIIIman089

Supramania Contributor
Mar 30, 2005
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Ohio
If the shifter is moving, I doubt its behind you. Sounds more like broken motor mounts.

In the event that they are OK, check the rear subframe for cracks.
 
Gargoyle

Gargoyle

New Member
Mar 13, 2006
159
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Portland, Oregon
The carrier bearing bolts are tight, the motor mounts are newer, haven't checked the rear subframe, but doubt I broke it when doing the trans swap.

Yes, the shifter bounces with the thump ....which in and of itself is odd to me since it is not actually mounted to the trans like on a stick. The movement is noticeable but it's not moving inches or anything. Just noticeable because of the noise I imagine.

I have also checked to see (by eye, nothing scientific) if perhaps I had the trans output kicked to one side or the carrier bearing off but they look okay and I would imagine that if that was the problem, the problem would persist to higher speeds.

Thank you for the input thus far, will check the subframe next time I get my buddies house (where the car and jacks are located).

Brian
 
M

mkIIIman089

Supramania Contributor
Mar 30, 2005
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Ohio
It would be difficult for you to break the subframe by swapping a transmission, it would have already happened. I suppose it could have been caused by any abnormal shock or vibration from the carrier bearing being way out of spec.
 
Gargoyle

Gargoyle

New Member
Mar 13, 2006
159
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Portland, Oregon
My question is: do you think it is just coincidence that this just started after the tranny swap? Is there a possibility that the problem is in the tranny?

Which suspension bushing, if you have a certain one in mind?
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
Brian: Did you inspect the trans mount?

They can be totally ripped but stay in one piece due to the torque limiter bolt in the middle of them. (I left one on when I had parts cryo'd and the rubber fell out but the mount was still in one piece)
 
Gargoyle

Gargoyle

New Member
Mar 13, 2006
159
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Portland, Oregon
When I did the tranny swap both trannies had mounts on them. The mount on the tranny I replaced was not connected to the metal bottom piece and the donor was in one piece and seemed to be solid. Is there still a possibility that the mount is bad? No biggie replacing it but since it was in one piece, unlike the old one, I didn't bother with it.

I had the center bolt out of the replacement mount and it looked to be solid even with it not there.

I hate that my car is making me feel like such a noob.:icon_evil

Brian
 
Gargoyle

Gargoyle

New Member
Mar 13, 2006
159
0
0
Portland, Oregon
Ok, time for an update and another quesiton. I went over to my buddies house and put the car in the air with the rear wheels off the ground. I couldn't feel any vibration or thump when running up the speed but as soon as I ran brake and throttle the whole car started to shake/rumble.

Climbing under the car while this was going on it looks the dog wagging its tail instead of the tail wagging the dog, what I mean is- The trans looks like it is the problem. The driveline is running straight and solid after the carrrier bearing but the tranny is shaking to beat the band. I did check the trans mount again and it is solid. I also have a loose output from the diff to the right rear but that is another project.

My question is....Is there anything in the tail of the auto trans that can go out/wear to the point of causing this...a bushing, bearing, or the like? Second part of the quesiton is.. Does anyone in the PDX area know of a decently priced and good tranny rebuild shop that is familiar with these transmissions?

As far as I could tell the rear subframe looked good.

Thank you all for the input, and sorry about the not so timely response as to what I have found.

Brian
 
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