Dirtleg
BoostCreep
Good morning hope everyone had a great christmas holiday.
First I'll just go on and say I screwed up the diagnosis of this problem.
And still am screwing it up.
A little background about this issue.
About 3 1/2 years ago I swapped an MT82 into my 07'. From day one it had a pretty loud input shaft gear whine. I drove it that way for a little while because I was working on getting the hall effect speed sensor in the MT82 to work with the 07' instrument cluster/computer. Waited months for a signal adapter that I never did get to work before having what I thought was a major transmission failure. (I will say the gear spread was awesome behind the 4.6. Loved it.)
So at that point I decided to throw my TR3650 back in. Once it was installed the exact same problem was there. Now I didn't think it was the drive shaft as the 2 setups have different driveshafts and what would the chances of that be.
Now I'll go on and admit I blew it at this point in diagnosing the issue.
What I did next was just dumb. I went ahead and ordered a rebuilt transmission as the original TR3650 had been making some unpleasant noises before I threw the MT82 in there and I just figured it had been kicked around and moved when it was out of the car so I may have jacked it up further before re-installing it.
Well I was wrong. The rebuilt transmission did not get rid of the problem in any way. It was exactly the same as before.
So at this point I decided to just go ahead and redo the rear axle. I know throwing parts at a problem is expensive and time consuming but the car has 150K on it and is not my daily at this point. I have decided to make it a track day car and thought rebuilding the rear axle would be good insurance once I start running it hard.
Well one thing led to another and I ended up putting in FRPP 3.55 gears (same as stock), all new bearings and seals, and a carbon traction lok clutch set. I thought I was careful in re-assembling everything. I torqued the pinion flange until I had 25 in-lb of rotating resistance, backlash came in at .008" and carrier caps were properly torqued. Gear pattern was centered on the ring gear although it did seem a little wide. I then proceeded to re-install the axle under the car and finish assembling everything. While I had it apart I put in new BMR lower and upper control arms, relocation brackets and an upper mount. I also changed the upper control arm bushing at the differential.
At this point I took it for a test drive and the problem was still there. So I climbed under the car and checked the driveshaft center bearing. It seemed to me there was excessive play in it so since I'm already so far down the rabbit hole I ordered and installed a driveshaft shop 1 piece aluminum driveshaft. Still has the problem although I'll admit it's improved some. Before the driveshaft it was damn near impossible to get the car moving from a dead stop. Afterwards it's not a problem to get started but the shuddering on off throttle, clashing noises are still there.
So now I'm scratching my head trying to figure out what's wrong. Is my rebuilt transmission screwed up too? Did I fail to set up the rear end properly in the exact same way it was wrong before disassembly?
I'm thinking somehow the pinion preload changed during assembly but not sure how it could have happened.
I've linked a video of the noise. I'm open to hearing any and all ideas at this point.
https://youtu.be/Xx7SMGlFbnM
First I'll just go on and say I screwed up the diagnosis of this problem.
And still am screwing it up.
A little background about this issue.
About 3 1/2 years ago I swapped an MT82 into my 07'. From day one it had a pretty loud input shaft gear whine. I drove it that way for a little while because I was working on getting the hall effect speed sensor in the MT82 to work with the 07' instrument cluster/computer. Waited months for a signal adapter that I never did get to work before having what I thought was a major transmission failure. (I will say the gear spread was awesome behind the 4.6. Loved it.)
So at that point I decided to throw my TR3650 back in. Once it was installed the exact same problem was there. Now I didn't think it was the drive shaft as the 2 setups have different driveshafts and what would the chances of that be.
Now I'll go on and admit I blew it at this point in diagnosing the issue.
What I did next was just dumb. I went ahead and ordered a rebuilt transmission as the original TR3650 had been making some unpleasant noises before I threw the MT82 in there and I just figured it had been kicked around and moved when it was out of the car so I may have jacked it up further before re-installing it.
Well I was wrong. The rebuilt transmission did not get rid of the problem in any way. It was exactly the same as before.
So at this point I decided to just go ahead and redo the rear axle. I know throwing parts at a problem is expensive and time consuming but the car has 150K on it and is not my daily at this point. I have decided to make it a track day car and thought rebuilding the rear axle would be good insurance once I start running it hard.
Well one thing led to another and I ended up putting in FRPP 3.55 gears (same as stock), all new bearings and seals, and a carbon traction lok clutch set. I thought I was careful in re-assembling everything. I torqued the pinion flange until I had 25 in-lb of rotating resistance, backlash came in at .008" and carrier caps were properly torqued. Gear pattern was centered on the ring gear although it did seem a little wide. I then proceeded to re-install the axle under the car and finish assembling everything. While I had it apart I put in new BMR lower and upper control arms, relocation brackets and an upper mount. I also changed the upper control arm bushing at the differential.
At this point I took it for a test drive and the problem was still there. So I climbed under the car and checked the driveshaft center bearing. It seemed to me there was excessive play in it so since I'm already so far down the rabbit hole I ordered and installed a driveshaft shop 1 piece aluminum driveshaft. Still has the problem although I'll admit it's improved some. Before the driveshaft it was damn near impossible to get the car moving from a dead stop. Afterwards it's not a problem to get started but the shuddering on off throttle, clashing noises are still there.
So now I'm scratching my head trying to figure out what's wrong. Is my rebuilt transmission screwed up too? Did I fail to set up the rear end properly in the exact same way it was wrong before disassembly?
I'm thinking somehow the pinion preload changed during assembly but not sure how it could have happened.
I've linked a video of the noise. I'm open to hearing any and all ideas at this point.
https://youtu.be/Xx7SMGlFbnM
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