Grinding in reverse 97 expy
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Grinding in reverse 97 expy
I just replaced my rear end clutch packs and still have he rumbling in the rear end not as pronounced now. Took it for a test drive and noticed that when in four wheel drive high or low when in reverse and sharp turning in any direction the rear wheels seem like they want to lock up because they are screeching. Any help would be greatly appreciated!! 97 expy 5.4 eb awd 139000 miles
PLEASE HELP
PLEASE HELP
Elder User
Joined: Jun 2004
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From: Orlando, Fla
Ok, could be one of two things, the 'emergency' brake calibration pintle is adjusting while in reverse, thus locking up the emergency brakes. Second, you may have a differential shim breaking down and causing binding. A slim chance is it also could be the pinion. I know its vague, but conceled areas aren't exactly easy to diagnose.
I would start with removing the rear rotors to see if those calibrators are set properly. Check for blueing from excessive heat or ridging from the pads being set out too much. Also while you have this exposed see if you can find any play in the axle or slop. Turn the axles forward/backward, try to jiggle it and try pulling them in and out checking for slack. Of course we're talking about slight movement on the in/out and jiggle points. You'll get movement turning them if both wheels are off the ground, but listen for grinding or the like. You may want to put it in neutral while off the ground and using the wheel to rotate it. MAKE SURE YOUR FRONT WHEELS ARE BLOCKED!
I would start with removing the rear rotors to see if those calibrators are set properly. Check for blueing from excessive heat or ridging from the pads being set out too much. Also while you have this exposed see if you can find any play in the axle or slop. Turn the axles forward/backward, try to jiggle it and try pulling them in and out checking for slack. Of course we're talking about slight movement on the in/out and jiggle points. You'll get movement turning them if both wheels are off the ground, but listen for grinding or the like. You may want to put it in neutral while off the ground and using the wheel to rotate it. MAKE SURE YOUR FRONT WHEELS ARE BLOCKED!
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I checked all of that when I replaced the clutch packs. What i did notice was that when I was checking the u-joints i noticed that the drive shaft would turn maybe about a inch or two before it stopped. I don't know if it is normal but i would move it back and forth and hear a little clunk when it stopped
Originally Posted by High_Horse
Ok, could be one of two things, the 'emergency' brake calibration pintle is adjusting while in reverse, thus locking up the emergency brakes. Second, you may have a differential shim breaking down and causing binding. A slim chance is it also could be the pinion. I know its vague, but conceled areas aren't exactly easy to diagnose.
I would start with removing the rear rotors to see if those calibrators are set properly. Check for blueing from excessive heat or ridging from the pads being set out too much. Also while you have this exposed see if you can find any play in the axle or slop. Turn the axles forward/backward, try to jiggle it and try pulling them in and out checking for slack. Of course we're talking about slight movement on the in/out and jiggle points. You'll get movement turning them if both wheels are off the ground, but listen for grinding or the like. You may want to put it in neutral while off the ground and using the wheel to rotate it. MAKE SURE YOUR FRONT WHEELS ARE BLOCKED!
I would start with removing the rear rotors to see if those calibrators are set properly. Check for blueing from excessive heat or ridging from the pads being set out too much. Also while you have this exposed see if you can find any play in the axle or slop. Turn the axles forward/backward, try to jiggle it and try pulling them in and out checking for slack. Of course we're talking about slight movement on the in/out and jiggle points. You'll get movement turning them if both wheels are off the ground, but listen for grinding or the like. You may want to put it in neutral while off the ground and using the wheel to rotate it. MAKE SURE YOUR FRONT WHEELS ARE BLOCKED!
Elder User
Joined: Jun 2004
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From: Orlando, Fla
Slop such as being able to move it up and down or try shaking it to see if it 'rattles'. Sounds extreme, but can be telling. Pinions are supposed to be tight all around. If when you rotate it it feels loose 'sloppy' it most likely will be your differential. Could be something like shimming needing done to tighten it back up.
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On that locking up in reverse issue could i drive without the rear brakes to test to see if that would happen
Originally Posted by High_Horse
Slop such as being able to move it up and down or try shaking it to see if it 'rattles'. Sounds extreme, but can be telling. Pinions are supposed to be tight all around. If when you rotate it it feels loose 'sloppy' it most likely will be your differential. Could be something like shimming needing done to tighten it back up.
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Elder User
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From: Orlando, Fla
Are you speaking of removing the pads? If so you will need to tie off where the pads seat so the parts don't come out. Also, does this do this when only in 4 wheel or will it do it in 2 wheel? If it will do it in 2 wheel, I would put the rear on stands and try it in reverse then.
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it only happens in 4wd and turning in reverse. it does not happen when i am going in a straight line in reverse and when I start to turn it start to seem to try to lock up
Originally Posted by High_Horse
Are you speaking of removing the pads? If so you will need to tie off where the pads seat so the parts don't come out. Also, does this do this when only in 4 wheel or will it do it in 2 wheel? If it will do it in 2 wheel, I would put the rear on stands and try it in reverse then.
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From: Orlando, Fla
That really sounds like the differential needs shimming, but it should be doing it all the time in reverse then, 2 or 4.
The only other compilation I can come up with would be the transfer case ratio is so mismatched with the reverse of the tranny and differential its binding and causing the lockup.
The only other compilation I can come up with would be the transfer case ratio is so mismatched with the reverse of the tranny and differential its binding and causing the lockup.
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Help!!!! 4wd Lockup
I rechecked everything and now it only happens when turning left or right in forward or reverse in 4wd. I can drive in a straight line back and forth in 4wd and nothing happens but when i go to turn the truck it will stop and I have to press the gas a little to get it going an when I take my foot off the gas it will stop again. #%@t this is %$#ked up. Please, Please somebody HELP. I don't want to take it to the dealer but i seem like I will have no other choice!!!!
Originally Posted by High_Horse
That really sounds like the differential needs shimming, but it should be doing it all the time in reverse then, 2 or 4.
The only other compilation I can come up with would be the transfer case ratio is so mismatched with the reverse of the tranny and differential its binding and causing the lockup.
The only other compilation I can come up with would be the transfer case ratio is so mismatched with the reverse of the tranny and differential its binding and causing the lockup.
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Yes I did the one that comes from ford. one guy at my job told me that it could be in the front end because when the 4WD is ingaged that something in the front wheels my be causing it to stop the truck. I am starting to think that it could be the transfer case because it doesn't do anything until you have to use 4WD any suggestions would help!!!
Originally Posted by pdqford
Sounds to me like maybe the clutches are chattering with differential action.Did you use a slip-lock additive?
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From: Central NYS
Originally Posted by mrman0901
I am starting to think that it could be the transfer case because it doesn't do anything until you have to use 4WD any suggestions would help!!!
My son's 2000 Expy Owner's Guide says that you shouldn't use 4H or 4L on dry surfaces (I'm assuming that's because the transfer case mechanically locks the two axles together). If there is no differential action in the transfer case when you turn and the tires can't slip, the drive train will bind up. I believe when your in AWD the axles are not mechanically locked and the computer controls the clutch action in the transfer case to allow the two axles to operate at different speeds while turning.