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What would cause a "loose" feel in the drivetrain? by JumpStart
Started on: 07-07-2014 01:50 PM
Replies: 10 (538 views)
Last post by: Puglet01 on 07-21-2014 10:10 PM
JumpStart
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Report this Post07-07-2014 01:50 PM Click Here to See the Profile for JumpStartClick Here to Email JumpStartSend a Private Message to JumpStartEdit/Delete MessageReply w/QuoteDirect Link to This Post
'86 w/3800sc and Beretta 5spd, Between acceleration and deceleration it feels like there is a loose spot like slop in the drivetrain. I have felt this on other cars even with automatics. It also has another feel to it that I can't quite put my finger on, It's like the cradle is turning maybe, like one wheel is pulling ahead of the other although the car does keep going straight. It just feels like something is moving and shouldn't be. It has the original axles and CV joints I assume, original cradle bushings and no dogbone. Any one have any ideas or noticed this before? I just want this car to feel tight. Most everything else is new using Moog parts.

Thanks,

Steve
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Old Lar
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Report this Post07-07-2014 02:59 PM Click Here to See the Profile for Old LarSend a Private Message to Old LarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Motor mount or transmission mount?
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2.5
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Report this Post07-07-2014 03:05 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Did you say it has no dogbone?

Also an improper alignment can feel like that.

[This message has been edited by 2.5 (edited 07-07-2014).]

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Formula88
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Report this Post07-07-2014 03:36 PM Click Here to See the Profile for Formula88Send a Private Message to Formula88Edit/Delete MessageReply w/QuoteDirect Link to This Post
Something *is* loose. It's just a matter of figuring out what.
No dog bone could be part of it.
Engine, tranny mounts.
Cradle mounts.
Any suspension bolts/bushings.
Loose axle bolts.

Once you've verified everything is solid, then I'd look at alignment settings. Be careful doing just a visual inspection. I've seen mounts separate where they looked perfect at rest, but under load the rubber and metal had completely separated. If you have a mix of solid/rubber/poly mounts, that can cause the weakest link to fail more rapidly. You should use all the same type mounts for best reliability.
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phonedawgz
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Report this Post07-07-2014 05:00 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have you tried shifting between forward and reverse while holding the brake and having someone watch to see which rear wheel(s) is moving?
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fastblack
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Report this Post07-07-2014 05:44 PM Click Here to See the Profile for fastblackSend a Private Message to fastblackEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'd start with an alignment and go from there. Heck, they might even find what's at fault while doing the alignment. My 87 had bad inner tie rod ends in the back when I bought it that made the rear end shift around when accelerating or decelerating. If nothing else, put in a dog bone mount.

[This message has been edited by fastblack (edited 07-07-2014).]

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JumpStart
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Report this Post07-07-2014 07:00 PM Click Here to See the Profile for JumpStartClick Here to Email JumpStartSend a Private Message to JumpStartEdit/Delete MessageReply w/QuoteDirect Link to This Post
No dogbone...yet
Motor mounts are PR's mounts and new
Tranny mounts are Rodney's and new
Just had an alignment
Suspension parts are new which include,
tow rods
all tie rod ends
all control arm bushings
all ball joints upper and lower
Sensa trak shocks and struts
steering rack
steering dampener

 
quote
Originally posted by phonedawgz:

Have you tried shifting between forward and reverse while holding the brake and having someone watch to see which rear wheel(s) is moving?


No, they should both move unless one spins?

When shifting, there just feels like a lot of slop there too. If you are not careful shifting, it can bang around like slop in the transmission maybe?

Steve
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Neils88
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Report this Post07-07-2014 08:01 PM Click Here to See the Profile for Neils88Click Here to Email Neils88Send a Private Message to Neils88Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by JumpStart:

No dogbone...yet
Motor mounts are PR's mounts and new
Tranny mounts are Rodney's and new
Just had an alignment
Suspension parts are new which include,
tow rods
all tie rod ends
all control arm bushings
all ball joints upper and lower
Sensa trak shocks and struts
steering rack
steering dampener


No, they should both move unless one spins?

When shifting, there just feels like a lot of slop there too. If you are not careful shifting, it can bang around like slop in the transmission maybe?

Steve


You didn't mention the cradle bolts. Make sure they are tight. Loose bolts will give the symptoms you describe. If they were loose when you got your alignment, you'll need to get it done again.
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Puglet01
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Report this Post07-16-2014 09:19 AM Click Here to See the Profile for Puglet01Send a Private Message to Puglet01Edit/Delete MessageReply w/QuoteDirect Link to This Post
I have an 86 GT and it's doing the same thing and it's getting more noticable. When I accelerate the car yaws a bit to the left and when I decelerate I can feel it yaw back to the right. I also noticed my right rear tire is worn more on the outer edge than the left rear. I'm off the next few days and the car will go into drydock over the weekend and have the rear tires replaced. I suspect a worn bushing somewhere or something is loose. About 4 years ago I put in a 3.4 and had the cradel done over and replaced the rear struts. I put in all new poly bushings on the cradel and had the car aligned. I'll let you know what I find out.
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katatak
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Report this Post07-16-2014 10:26 PM Click Here to See the Profile for katatakSend a Private Message to katatakEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check your Axle Nuts for proper torque! I say again - Check Your Axle Nuts for Proper Torque! I have seen loose axle nuts cause the ass end to be "loose" under acceleration and deceleration!
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Puglet01
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Report this Post07-21-2014 10:10 PM Click Here to See the Profile for Puglet01Send a Private Message to Puglet01Edit/Delete MessageReply w/QuoteDirect Link to This Post
Last Thursday I jacked up the back end and checked it out. Everything appeared tight. I didn't remember but when I put it all together 5 years ago I had replaced all the rear control arm bushings with poly ones. I replaced my rear tires and scheduled an alignment at Sears for the next day. Turns out the right front upper control arm had a worn out bushing. The back end of the control arm could move about a 1/4 inch. When I took off the control arm the top rear bushing just fell out. It was worn all the way thru on the inside. I also had a bad left wheel bearing. I have been neglecting the front end since I replaced the front struts back in 2006. While I have the front end torn apart I'm replacing the ball joints, tie rod ends, bushings, bearings, shocks, and rotors. Some time back in 2000 when I first got the car I did a front brake upgrade and put Beretta rotors and calipers on. I was always a bit skeptical about my brother-in-law's machine work. Now I have my own lathe and I'll do the machining myself. When it's finished the steering should feel tight again instead of like a Walmart shopping cart.
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