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99 silverado drivetrain


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gpingu87
New User

Dec 27, 2012, 10:54 PM

Post #1 of 5 (5285 views)
99 silverado drivetrain Sign In

 99 silverado 1500 5.3l 4x4 automatic 240k- No reverse. When I placed the truck in reverse, there was a whining grinding noise. When driving, anything over 10mph causes grinding whining noise. If I take it to speed and drop to neutral, no grinding. shifts from 1-4 fine no problem, outside of the grinding. Thought it may be it was a problem with the transfer case. I pulled the transfer case out. Everything seemed fine with the transfer case, although I noticed it was a red fluid in it, the fluid i got form the dealer was blue, possibly transmission fluid? Previous owner told me he had it replaced before I bought it. I spun the output shaft on the transmission, and the grinding noise was in the transmission. Truck in park, I could spin the output shaft. I started the truck and the trans output shaft spins while still in park. Put it into reverse for just a moment, and the grinding was there, Am I needed a new transmission? or maybe some kind of external sensor? There was no load breaking noise or any event that would cause alarm leading up to the problem. Any advice/ incite is greatly appreciated .

edited for mileage


(This post was edited by gpingu87 on Dec 27, 2012, 10:57 PM)


Discretesignals
Ultimate Carjunky / Moderator
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Dec 27, 2012, 11:03 PM

Post #2 of 5 (5275 views)
Re: 99 silverado drivetrain Sign In

Transmission has to come apart and inspected. More than likely it will be cheaper to buy a reman. Could be a planetary that is coming apart.

The blue Autotrak II fluid is the improved version of the red Autotrak I fluid. Dealer doesn't sell the red stuff anymore.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 27, 2012, 11:08 PM)


gpingu87
New User

Dec 27, 2012, 11:32 PM

Post #3 of 5 (5255 views)
Re: 99 silverado drivetrain Sign In

Any thought on the transfer case having red fluid in it? Should it be a large concern? Replacing/rebuilding the trans the only option? If i go grab a new trany out of a bone yard, will my transfer case be ok?

Also My friend has a 4l60e out of a 99 jimmy, any chance they are swappable? if his Transfer case swap-able? Would rather buy from a friend and help him unload his, than go to a bone yard if they are compatible


Discretesignals
Ultimate Carjunky / Moderator
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Dec 27, 2012, 11:56 PM

Post #4 of 5 (5249 views)
Re: 99 silverado drivetrain Sign In

If you have no reverse, the transmission has a mechanical problem. If it is grinding, that is really bad because you have metal being circulated around inside the transmission.

The red fluid being in the transfer case, as long as it is the older Autotrak fluid and not automatic transmission fluid, should be ok. Now if the transfer case fluid has never been serviced (which it probably hasn't), you should go ahead and do that after you get the transmission replaced or overhauled.

Which transmission do you have? 4L60E or 4L80E? Look in the glove box and you'll see a sticker with a whole bunch of numbers and letters on it.

If you see M30, you have the 4L60E. If you have MT1, it's a 4L80E.

The part number for the Jimmy's transmission is different. It might be physically the same, but there could be some differences in the valve body and seperator plate designs.

If you go with a bone yard transmission, make sure it is for the same year and application as your truck. Bad part is you won't know if it is good until you plug it in and drive it, so make sure it has some sort of warranty.

If you have some cash laying around or your a recently lottery winner, my recommendation is to a get a factory SERTA which has a 3 year 100,000 mile nationwide warranty. SERTA is a GM factory rebuilt transmission.

Do not forget to either replace or flush out your transmission cooler when you replace the transmission unless you want to trash your replacement. Also have a shop with a scan tool clear out the transmission learned adapts from the PCM memory or it will have shifting problems.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 28, 2012, 12:09 AM)


MarineGrunt
Enthusiast
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Jan 5, 2013, 11:53 AM

Post #5 of 5 (5172 views)
Re: 99 silverado drivetrain Sign In

Like DS said, the red fluid is an old version. In the past year we purchased a 2005 Envoy and a 2003 Sierra and both had the red fluid in the transfer case. If yours had the red fluid it means the transfer case was never serviced because GM now has the Auto-Trak II which is blue. I guess it could also be possible that someone didn't use the correct fluid when they serviced it. There are aftermarket fluids that are red but they're not recommended. Don't worry about the fluid being red. Just flush it good and start using the updated fluid.

This doesn't have anything to do with your current problem but if you have the transfer case pulled you might want to make sure the pump clip hasn't broke loose. There's a known issue with "pump rub" with GM transfer cases within a certain date range. I think it's 1998-2007. A little clip that holds the pump in place can break and cause the pump to rub on the rear housing. Over time it can rub a little hole in the case and allow fluid to leak out. It happened to my Sierra but I was lucky enough to notice it before the transfer case went completely dry. The only reason I found the hole was because it had been raining. I parked at a store and noticed the rainbow color of oil right where I had been driving to pull into the parking spot. I had to buy a new rear housing due to the hole. You normally don't see the fluid leaking because it only builds enough pressure to leak out of the hole when you're driving down the road. There's an updated wear plate that can be installed to prevent from ever having this problem. We were going to install the wear plate on my step dad's transfer case. His didn't have the wear hole but he wanted to do it for preventive maintenance. We split the case and the clip had already broke. The little broken pump clip breaking ended up causing about $500 in damaged parts. His clip breaking caused the pump to rattle around which eventually cracked the aluminum pump. Since fluid was no longer being pumped it caused all kinds of wear on all of the components. If you google "pump rub" you'll see what I'm talking about. There's a lot of info out there. I try and warn everyone about it who owns a GM vehicle within the date range of the problem. A $75 upgrade could possibly save you hundreds of dollars down the road.

One thing at a time though. Get that tranny fixed first.






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