Transmission issues or something else

Tiny
DABOSSS
  • MEMBER
  • 2007 GMC SIERRA
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 159,000 MILES
I have the truck listed above with a 7.5 inch Lift, and thirty five inch mud tires. Yesterday I was at a friends, as I went to back out of his freshly graveled driveway, I
placed my truck into reverse, The indicator was showing it was in reverse,
and I felt the transmission shift, However, as I started backing up, it
sounded like an old party whistle as indicated in the image below. I tossed
the truck into neutral rather quick, allowed the noise to stop, then placed it
into park again. After a few seconds and me scratching my head, I tried it
again. This time there were no issues what so ever. It shifted normally,
and I was able to back right out, I was rather easy on the acceleration
backing out since that issues had just took place, I did not want to risk
causing any more damage to whatever happened. Occasionally I will get a
loud clunk and a extremely hard jerk as I put it into reverse and start to
accelerate, almost as if the front end or the transmission wants to drop out
completely. What on earth could be going wrong with my transmission? I know
those lift kits are hard on parts, but to cause my transmission to do all this?
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have the same problem?
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Wednesday, January 25th, 2017 AT 2:30 PM

6 Replies

Tiny
HMAC300
  • EXPERT
Due to the nature of this problem you should have a transmission professional check this as he may have run into this before. Due to the lift it may be out of alignment.
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Wednesday, January 25th, 2017 AT 3:49 PM
Tiny
STEVE W.
  • EXPERT
Check the pinion angles and the drive shaft angles at the T-case. They need to be the same angle or you will get binding in the joints. Quite a few lifts tilt the axles and mess the angles up. The binding will cause a lot of different issues.

As to the whistle, maybe a dry idler bearing or belt squeal from moisture?
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Wednesday, January 25th, 2017 AT 8:31 PM
Tiny
DABOSSS
  • MEMBER
Funny thing is, or not so funny thing, depends on how one looks at it. I did not start having these issues until I had the U joints replaced a few months ago, after having them replaced is when all these other issues cropped up. And it took it about a month and half before the first issue arose.
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Thursday, January 26th, 2017 AT 11:58 AM
Tiny
HMAC300
  • EXPERT
Then if you have a grease fitting on u joints grease them then do what Steve W says. Lifting trucks as well as adding hp causes all types of problems.
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Thursday, January 26th, 2017 AT 12:09 PM
Tiny
DABOSSS
  • MEMBER
I will give it a shot and see what happens.
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Thursday, January 26th, 2017 AT 12:11 PM
Tiny
STEVE W.
  • EXPERT
If the noise started after a U-joint was replaced, pull the shaft out and check the joint. It's possible that one of the bearings has a problem and the joint is binding up. Have seen rollers get stuck between the cross and the cap and create problems.
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Thursday, January 26th, 2017 AT 1:57 PM

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