Wasn't sure if this belongs in the "transmission" section or not...........

I just got my car back from having a new (used) 2JZ-GE installed into my SC3. Engine seems to run great, even has a much throatier sound than my old one. My problem is that it seems the shop has some how badly FUBARed my driveline. From a stand still, I have to slowly (and I mean SLOWLY!) accelerate b/c there is a bad vibration or knocking in my driveline; it feels like I'm driving over a rumble strip or something. Also, I barely feel it at higher speeds, but at around 70 it makes a loud hum - at first I thought it was the exhaust. It feels like it's coming from directly behind the tranny, right under the arm rest. Anyways, the shop found a bunch of loose bolts and whatnot that one of their guys didn't torque down, and that didn't solve the problem. I think the "center bearing" that the driveshaft runs through is the culprit (b/c there is a 1/4 or 1/2 inch gap between the shaft and bearing itself), or they left out a brace (SEE PIC BELOW). They told me they don't know what it is, but think the 1st gear clutch pack in my tranny is going bad. It's not. Anyways here's my question - does somebody have or be willing to take some detailed pics of they're under carriage? I suspect the shop lost a part or simply didn't put it back in, but I need the see what an SC3 should look like in order to make a comparison.


Here is a pic or a brace-like part that I found in the box-o-stuff I picked up from the shop. It looks like it belongs somewhere under the car, but I don't know. Gatorade bottle is for size reference.

 

Schematic or drivetrain. I cirlced the center bearing in red. PLEASE HELP! THANKS IN ADVNACE! Oh, also.... diagram is from "Mitchell On-Demand" Repair manual. $30 with shipping off of e-bay for the Lexus manual.... GREAT alternative to the high-priced paper manual.

 

That looks like the brace that secures the exhaust to the tranny. It connects near the cat, and the single bolt hole secures it to a tranny bolt. Most remove anyways when putting on custom exhaust.

 

Chris is correct. That's the midpipe/dp support bracket that's attached to the bottom of the bell housing. If you have the OEM exhaust, there's a slight possibility that the exhaust is vibrating. It's more likely that the center bearing is bad; or the pumpkin is bad. If you have an OEM driveshaft that isn't modified, then it should be balanced.

-scott

 

my 300zxtt did the same thing when the driveshaft was going out...

you have to accelerate slowly to get up to speed and then it was bearable... but it was a bump bump bump bump sound; very consistent with the rotation of something...

when the engine shop mounted your tranny back in; make sure they aligned your driveshaft... things dont just go bad like that instantly... sounds like something got installed wrong

 

Thanks for your help and info, guys! Yes, the shop did INcorrectly line-up my drive shaft; I took it to another shop to have it fixed. It still vibrates a little, but I think that is because my tranny mounts are bad now after putting 200 miles on the car vibrating like that. I think you're right about the exhaust vibrating, too. I'll check it out. Thanks again!!!

 

Anyone who is getting any transmission work done or rear end work done should have a serious chat with whoever is doing the work.
Whenever a drive line is taken out ALL pieces that are taken out must be bookmarked with the mating piece and put back precisely the way they came apart.
The driveline of a Lexus is very finely balanced and if things are rotated even 1 or 2 degrees from what they were originally then there will be balance problems in the driveline causing noises and vibrations.

I have a problem with my driveshaft and was planning to buy a used one from the auto wrecker.

When I went to pick it up the guys grabbed the 2 shafts which had been seperated.
When I asked if they had maked the spline so it could be joined back the way it was dismantled they looked at me with blank stares.
Found out they could not even guarantee that the front and rear shafts were off the same car--never mind actually marking them so they would be balanced.
Needless to say I walked away without purchasing as the lack of bookmarking the 2 shafts would I believe cause major problems and quite possible would never be balanced in the future.

There is a reason why there are little balance weights attached to both driveshafts on a Lexus.

So best to keep this in mind when having any drive line work done.

Rob

 

i would never bring my car to a small shop.to do big jobs,that require upto date specialized equipment that only a dealership can afford. most small shops have a different mechanic every month.you would prob save a couple of bucks, but the problems you will have from there on, will be priceless.if there isnt a lexus dealer near you, bring it to a toyota dealer.or any dealer ship that has upto date equipment and CERTIFIED mechanics.you would NEVER get a box of left over parts after you fix something on your car if you bring it there.everything MUST go back on the car. the only thing left over, should ONLY be the part you REPLACED.
leftover parts =

 

killerlex
I agree with your statement that leftover parts are a major problem.

I deal with a very small shop and the mechanic / owner is an excellent mechanic.
He is just starting to learn the Lexus SC 400 by working on my newly acquired 93 SC 400.

I am quite sure that if he had "leftover parts" other than the parts he replaced he would be very worried.
.
Key to using a small local shop is to have the service manual for your car available so the mechanic has literature to refer to.
Lexus and other dealerships tend to overcharge big time when it comes to working on a high end car like a Lexus.
About 90 % of the repairs on a Lexus do not require any specialty tools and most mechanics can do just as good a job as the supposed Lexus Specialists, with usually about 1/2 the charges you would be charged at the Lexus Dealership.

These car may go like Rockets but they do not require a Rocket Scientist to repair them.
.
The key is to buy the 2 Volumes of the Workshop Manuals for your car and have them available to the shop you have your car at.
.
Like I said earlier the Workshop Manuals for my SC 400 is the best investment I have made to date in my SC 400. It will probably save me a considerable amount of money in the future.

Rob

 

It cost me $4,000 to do this big job from a small shop. The shop has 3 mechanics who are all there 6 days a week. I suggest you price a DEALER to swap in a new/used engine; it's not saving "a couple bucks", but more like saving $1,000 or more. And for the record, I bought @ $800 in new parts (water pump, timing belt, etc.) to be put on, and kept the pulled engine so in that case you WILL have a left-over parts box (I have 2).

You know what you are talking about; you sound as if you know from experience, too. Also, I did give them an electronic shop manual.