Polyurethane engine and trans mounts
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Joined: Nov 2015
Posts: 1,362
Likes: 93
From: Salem OR
AMG's, CTS-V's, SRT's
Took it out this morning for some hard pulls. All is good! After resetting the poly bushing the shifter doesnt move at all. Pulls hard, shifts hard, and no jerks.
I may do the tranny fluid again, maybe after 10k miles. I can really smell the clutch materials in the fluid when the car jerks in and out of D so violently.
Here's what I learned:
symptoms:
Hard jerking when accelerating med-hard.
Hard jerking / lurching when accelerating from a med-steep hill
Shift lever creeps towards the front of the car when accelerating
shift lever creeps towards the rear of the car when braking.
Cause:
Engine and transmission is jerking, pushing on the shift-rod, pushing the gear selector briefly from D to N.
This is caused by any of the following:
1. engine transmission bushings bad
2. rear sub frame mount torn or badly worn
3. shfiter rod needs to be adjusted. (maybe you installed a new shifter unit like i did )
Fix:
For me, I did the engine trans mounts less than a year ago. I inspected the subframe mounts and they are all tight. I adjusted the shift rod under the car, on top of the drive shaft. I made it shorter, which angles the shift selector more towards the rear of the car. This helped a little bit, but during really hard acceleration, it still failed.
I inspected the trans bushing again and found that the bolts have worked themselves loose. The new mount I installed also had a small tear in it.
I purchased the poly mounts from Creative steel. I installed them incorrectly. I torqued them down with the engine still supported. This caused them to be installed under stress when lowered. When I took it for test drive the problem was worse somehow.
Then I double checked the poly mounts, It was torqued in, but twisted a bit, putting them under stress. I loosened and retorqued the transmission poly mounts AND re-adjusted the shift rod under the car. I made it as short as possible, without binding. I took it out for some hard pulls, and the shift lever does not move at all.
I may do the tranny fluid again, maybe after 10k miles. I can really smell the clutch materials in the fluid when the car jerks in and out of D so violently.
Here's what I learned:
symptoms:
Hard jerking when accelerating med-hard.
Hard jerking / lurching when accelerating from a med-steep hill
Shift lever creeps towards the front of the car when accelerating
shift lever creeps towards the rear of the car when braking.
Cause:
Engine and transmission is jerking, pushing on the shift-rod, pushing the gear selector briefly from D to N.
This is caused by any of the following:
1. engine transmission bushings bad
2. rear sub frame mount torn or badly worn
3. shfiter rod needs to be adjusted. (maybe you installed a new shifter unit like i did )
Fix:
For me, I did the engine trans mounts less than a year ago. I inspected the subframe mounts and they are all tight. I adjusted the shift rod under the car, on top of the drive shaft. I made it shorter, which angles the shift selector more towards the rear of the car. This helped a little bit, but during really hard acceleration, it still failed.
I inspected the trans bushing again and found that the bolts have worked themselves loose. The new mount I installed also had a small tear in it.
I purchased the poly mounts from Creative steel. I installed them incorrectly. I torqued them down with the engine still supported. This caused them to be installed under stress when lowered. When I took it for test drive the problem was worse somehow.
Then I double checked the poly mounts, It was torqued in, but twisted a bit, putting them under stress. I loosened and retorqued the transmission poly mounts AND re-adjusted the shift rod under the car. I made it as short as possible, without binding. I took it out for some hard pulls, and the shift lever does not move at all.
