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Daniel Wilson
Daniel Wilson,
Category: Chevy
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Experience:  Owner at DJ Wilson
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Chevrolet Suburban 1500 LS: I have a vibration at 70 MPH in

Customer Question

I have a vibration at 70 MPH in my 2002 chevy suburban 1500 4wd. Overhauled front diff, replaced front axels, replaced rear end, balanced drive shafts, twice, rebuilt transfer case, balanced tires, changed shocks, nothing has worked? Wondering if something in the transfer case could be out of balance or if something in the transmission could cause it. The vibration still occurs with the car in the driveway on jack stands, both drive shafts removed and a plug in the rear t-case output????
Submitted: 5 months ago.
Category: Chevy
Expert:  Daniel Wilson replied 5 months ago.
Hi Larry, My name is***** will be glad to help. Does the vibration occur out of gear neutral at any particular RPM or only when in gear on acceleration?
Customer: replied 5 months ago.
Only in Gear. Can put in neutral and speed up to the 2K RPM where vibration is but nothing in neutral.
Customer: replied 5 months ago.
After rebuilding transfer case the front output shaft seal leaked. I bought new national brand seal but it actually came out part way. Got a replacement from O'Reilly's, another National but it came out too. Does the front drive shaft in the transfer case get our of round or bent? I put the old factory original seal in and left the front drive line off and no leaks so far. If a problem exists in the T-case, the drive shafts will increase the feel of the vibration and maybe exacerbate the vibration? I've read flex plate cracks and torque converters are suspects too. My transmission shifts and seems to work properly. I sometimes hear a sound, like a high rpm whine or more like an engine fan that is under heavy load sound but not always there. This damn thing may be impossible.
Expert:  Daniel Wilson replied 5 months ago.
Thanks for the update. Drain the transmission and transfer case and check for burnt/discolored oil or metal/debris in the oil or bottom of the case. Check the transmission pan and filter for any metal/debris as well indicating internal problems. Check your motor and transmission mounts as well. I see it happens with the driveline disconnected which points to the transmission or transfer case. Let me know
Expert:  Daniel Wilson replied 5 months ago.
Yes a cracked flex plate is also another possibility.
Expert:  Daniel Wilson replied 5 months ago.
you should be able to see that with a light from under the vehicle with the inspection cover removed.
Customer: replied 5 months ago.
I drained the T case oil when I replaced the front output shaft seal, twice, and noticed some metal flakes in the oil but thought that may be normal "break-in" stuff? Also, when I split the transfer case, the oil pump line had fallen out of the pump. I don't know if I knocked it out or if it was already out? Put all new bearings, chain and gears, clutch plates, electric shifter, seals in the T-case but wonder about planetary gears and housing for clutch plates. That drum or housing appeared to have gotten very hot at some point but someone else told me they all look burned?
Expert:  Daniel Wilson replied 5 months ago.
Click on these two links as there was an update as the pump would wear through the case. Check for this problem.
Expert:  Daniel Wilson replied 5 months ago.
Hi Larry, Just following up to see if you still needed more help with this? Please remember to rate my service as that is how the experts get credit for their time helping on the site.
Customer: replied 5 months ago.
I already learned of the issue with the pump wearing a hole in the Tcase and actually replaced the back half of the case and added clips on the pump contact tabs to prevent future holes. Still have the vibration so back to original problem diagnosing if it is in the transmission. currently driving with front drive shaft off, seams to reduce the vibration, but again, it will vibrate at 70 mph with both shafts off. tried 70 mph in 2nd gear on highway and vibration didn't seam as bad. I just don't know anything about transmissions so hoping someone can say if a bearing in the trans could cause a high speed vibration? If it is a torque or flex plate, think they would vibrate even with the trans in neutral? Leaning to something wrong in the transmission but also fear parts in the Tcase like planetary gears, shafts, etc could have been bad when I replaced all bearings, seals, plates, etc. Seams like a hopeless case and worst problem I've ever experienced w a car!
Expert:  Daniel Wilson replied 5 months ago.
thanks for the update Larry, If the T case is the problem then it will show up in a hurry and produce metal in the oil. Drain it in a clean bucket and check for metal. If it is clean then it is likely not your problem. Service the transmission and check the pan for metal/debris indicating an internal problem and for discolored oil. Check the flex plate/flywheel for cracks that might cause a vibration from viewing from the inspection cover underneath and for crankshaft end play/possible harmonic balancer issues or a loose fan hub.

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