Slipping trany on a 2000 5.3 4X4 Silverado

[nhkid]

I just changed over my transmission fluid to Mobil 1 atf at 37K (about 1000 miles ago). I have heard on other forums that synthetic fluid may cause the transmission to slip. My transmission shifts fine once it is warmed up and I am driving conservatively. I do notice sometimes that if I drive more aggresively it shifts differently. What I mean by that is that it sounds like I have a manual and I am riding the clutch for a second or so. Is this slipping? I have noticed that sometimes if I apply more throttle just before it shifts it will do this also. I don't really notice this all the time it occurs occaisonally and more so when it is cold.
I did add Lubegard after the flush along with the atf.

Thanks for your input.

[ March 09, 2003, 08:37 PM: Message edited by: nhkid ]

 

[TheLoneRanger]

Nhkid, that sure sounds like slippage to me. It may be from a combination of the Lubegard with the Synthetic fluid. I have a Cherokee with the AW-4 transmission, and these are known to not do well with synthetic. I use the plain old garden variety M/D III in it. (But I do change it regularly.)

In my opinion, some fluids are just too "slippery" for some transmissions. The ATF coefficient of friction has to be matched with the transmission design.

 

[nhkid]

I was thinking that this was do to 'tricking the computer' by giving it gas just as it was preparing to shift. I am going to monitor this closely and see if I can pinpoint when it occurs.

 

[OneQuartLow]

Yep, I wouldn't add LubeGard to M1 ATF, at least not unless you're experimenting to fix an existing problem. That's very good ATF without supplements. Also, which LubeGard? Was it the Red or one of the friction modifier types?

What's the factory recommended ATF for this vehicle?

David

[ March 09, 2003, 10:50 PM: Message edited by: OneQuartLow ]

 

[nhkid]

David,

It takes Dex 3. I used Lubegard red. I am experimenting attempting to quiet down a torque converter shutter that I have. At least that is what I think I have. When the transmission shifts into overdrive at as early as 38 mph up to about 48 or so, it makes a noise like you are driving over rumble strips on the highway (except not at loud). Someone recommended that I try Lubegard red for this because it sounded like torque converter chatter.

I think that the combo of the Mobil 1 atf and the Lubegard has quieted this down some but has not eliminated it. When I drove home last night from work the transmission shifted flawlessly. I am thinking that I confuse the transmission computer when I give it gas as it is preparing to shift. This is causing it to shift funny.

 

[Greaser]

quote:

---

Originally posted by TheLoneRanger:
Nhkid, that sure sounds like slippage to me. It may be from a combination of the Lubegard with the Synthetic fluid. I have a Cherokee with the AW-4 transmission, and these are known to not do well with synthetic. I use the plain old garden variety M/D III in it. (But I do change it regularly.)

In my opinion, some fluids are just too "slippery" for some transmissions. The ATF coefficient of friction has to be matched with the transmission design.

---

My Cherokee runs great with the Mobil ATF..put it in last year..got about 13,000 miles on it with the Mobil...off-roading,towing,normal temps,fridgid temps...runs/shifts great

 

[RobZ71LM7]

It is NOT a fluid problem. There's a well-known TSB out on this problem. The TCC is locking up too soon and the pcm needs to be reporgrammed by the dealer to delay TCC lockup. Just have it reprogramemd your dealer will know about the TSB or should when you describe it.

 

[nhkid]

Rob,

I have been there and done that with many different dealers and they all say that I have the latest and greatest updates. I have been there so many times for this problem when they plug into my truck and try to get more updates from detroit they get locked out.

So this was like my last resort!!! I either deal with it or I drive in d3 unless I am above 50 mph or so.

 

[Drew99GT]

When I took my Grand Am to the pontiac dealer to have them install Mobil 1 ATF, they adamentally stated not to do it because it doesn't work well in many Dexron 3 required transaxles.

So I didn't!!

 

[Bror Jace]

You can increase the coefficient of friction in an ATF and eliminate slight slipping by adding a bottle of limited-slip differential additive.

This worked on my Dad's 1994 Mercury Grand marquis.

Many lube companies make this stuff and it's even available at GM dealerships. Comes in a 4oz bottle.

--- Bror Jace