BIGBADDAD

The trans was flushed a while back..a few thousand miles ago, and when I say lunge I guess I mean goes into gear hard, almost like U joints, but there is no "clunck". If you put it in reverse, and transition to drive it is not nearly as noticable. When I am driving and it shift, it is very smooth through all the gears, its only when I start it up and put it in drive. I dont know, but if I have to rip it apart to figure it out...I WILL.
Thank you,
I might get to the point of pulling the trans, just to check.
Mark

BIGBADDAD

Ok,
Its getting worse by the day...now even when it is shifting it rocks back and forth, it happens when it shifts up, and when it down shifts. I had it on the rack last night, and put a wrench on everything, I pryed every mount trying to see if it was broken...Nothing, what I did find was two of the bolts (on the same side) of the cross member that hold the trans mount were stripped, and just pushed in there, I replaced them, also I noticed that the fwd, and aft drive shaft (i dont know what you call them, U joints..but they are rubber) any ways they have tears in them, not serious, but they are there, I also pryed on the trans mount, it is in tact but very soft, I can move it all over the place. To the best of my ability I check the motor mounts, I put a trans lift under the oil pan and picked the engine up, they went up a good 1 1/2" but looked intact. I checked the rear end mounts they look good...It is to the point that my wife will not drive the car any more. I could really use some more help.
Thank you.
Mark

KevinfrmSD

Mine does the same but that's because i don't let it warm up.

black_LS

My trans mount looked fine, but it was far gone. Replace that, only $40.. and you can do it yourself.

BIGBADDAD

I ordered motor mounts, and I will order the trans mount today.
Thank you.
Mark

AHJ

Have you checked the throttle cable? The length does need to be adjusted and can cause simlar problems.

BIGBADDAD

No one has mentioned that as of yet. Could you walk me through the process.
Thank you.
Mark

LRP_LS400

throttle cable adjustment
https://www.clublexus.com/forums/sho...throttle+cable

flogdpup

BIGBADDAD,

I had a similar problem with my 94 LS. When I would put it in Drive the car would lurch forward and when I would put it in Reverse the car would lurch backward. No amount of warming up would help it and this happened after I had the motor and trans mounts replaced, so that wasn't the cause. The indy mechanic I took it to rechecked all the mounts and couldn't figure it out. Needless to say, it bugged the @#&%! out of me.

Well, all these problems turned out to be symptoms relating to a cracked EGR pipe. I finally got around to replacing it and it was unbelievable... I had a new car. It now idles, shifts (both manually and automatically), and accelerates, all smooth as silk. It turned out that the exhaust leak that I thought I had was actually a cracked EGR pipe, which I fixed and ended up fixing a whole list of other problems along with it. The bad news is that changing the EGR pipe is a pain in the ****!!

I changed my own and believe me when I say you will want to do it in private away from the spouse and small children unless you want to expand their vocabulary. You're in luck if you have small hands and skinny forearms because one of the bolts is a pain to reach and unscrew. There's two bolts on the rear of the intake manifold to remove where the EGR pipe connects and then there's another two bolts that can be reached from underneath the car where the EGR pipe attaches to the passenger side exhaust near the front (or main) oxygen sensor. The difficult part is loosening the bolt that attaches the center of the EGR pipe to the rear of the engine block. It's difficult because of the tight space between the motor and the firewall that you have to squeeze your hand into to get at the bolt. When I attached the new EGR pipe I left the 5th PITA bolt off, so if/when I have to change it again, it will be tons more easy.

The alternative is to take it to the shop and have it done. Be warned though that the repair manual says to drop the transmission to remove the EGR pipe which means, expensive labor costs. Either way, with your symptoms being so close to what I experienced, it would be worth your while to have your EGR pipe checked out. Good luck.

In the pic, #2 is the EGR pipe.

Lexushead

That's is odd indeed. What seems to be trans/mounts related turns out to be an ERG leakage.

BIGBADDAD

Wow,
I will look at it tonight when I am changing my motor mounts. How did you figure out that your EGR pipe was leaking. My LS4 runs great, idles great, it just shifts hard...not in reverse, only in drive, and then when it up shifts and down shifts it rocks back and forth, unless you have your foot in the accelerator, if you have your foot in it it shifts up pretty smooth????
Thank you for the info, I do appreciate it.
Mark

BIGBADDAD

Ok,
Now I am pissed off, I have had it. I replaced my motor mounts today...only took me 55 min. but in the process I broke my power steering hose, and when I went to replace that I broke the rubber ducting that goes to the throttle body, and the hose that goes from the air cleaner to the front of the engine (center) actually I have no idea where it goes, it follows the top of the radiator to the middle, and then into the engine...oh well, so I get this all fixed, drop it into drive and "thunk" it goes into gear and lunges, it doesnt actually move, it just goes into gear and you feel it grab..hard. So the mounts were not the problem, I just have no idea, im out $190.00, and if anyone is looking for a slightly used set of motor mounts let me know, they are only about 8 months old. So if anyone has any more info, Please share. I checked my EGR and the valve and pipe look fine no leaks either.
Thank you.
Mark

j stuff

iTrader: (5)

Ouch man sorry to hear

You dont happen to have a tutorial or anything on how to install the engine mounts do you? Im taking my car to my mechanically inclined friend to do trans and motor mounts.

Suneet

Thats for posting that bit about your cracked EGR pipe. I know I've got a cracked EGR pipe but haven't had the time to fix it.. I wonder what other problems it will solve!

BIGBADDAD

Its pretty easy if you have a lift, and a jack stand that will reach, I used an exhaust jack stand. I removed the bolts top and bottom (you will need a stubby 17mm box end wrench for the drivers side), there is a wire loom that runs across the front of your cross member, you will need to remove both 10mm bolts, in hind sight...you need to disconnect your power steering hose or you will brake it. I started with the passenger side, because it looked easier, and was. Once you remove the top/bottom bolts put your jack on the outside of the oil pan (you wont require enough pressure to hurt it) and slowly start jacking the motor up, I would use my foot to jack the motor, while me hand was on the mount so I would know when the mount had enough play to be removed, you have to slide the mount up, and then down and out. On the passenger side it comes right out...once out remove the heat shield, and metal keeper, you actually have to pry it off, and snap it on to the new mount, install it the same way you removed it.
As for the drivers side...there is a sending unit twards the front of the car, disconnect, and remove the unit, this will give the space you need to remove the mount, and even doing this, it will be very tight, but if you rotate the mount, wiggle it around, and even pry a little you can get it out, I removed the heat shield while it was still in place, you wont get it out with the shield still attached, so remove top and bottom bolts(this is where that stubby 17mm comes in handy you need it for the top bolt, I didn’t need it for the passenger side, but it would have made it easier) , position your jack to the other side gently lift, making sure nothing is binding, the motor mount goes up, and down and out, when you put the new mounts in you might have to raise the motor a little more due to the mounts not being squished. One thing I forgot was you will need to remove the splash pan.
I think that’s all, the trans mount is easy, you can look at it and tell how to remove and replace nothing special.
Hope that helps and good luck.
Mark