Slipping Tranny ? 2000 5.3 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.

 

[Ray H]

Which (color of bottle) Lubegard did you use?

 

[nhkid]

I an not sure I think it was red. Yea it was red I just double checked on their web site.

[ March 09, 2003, 10:07 PM: Message edited by: nhkid ]

 

[Ray H]

Lubegard "red" would be the appropriate product in a G.M. transmission. But I have the impression Lubegard intends their products to be used with conventional Dexron III ATF. Mobil 1 ATF is, after all, a full PAO-based synthetic, so I wonder if the addition of even Lubegard Red is too much of a good thing. My own best guess is that you're not facing an immediate transmission tear-down, but it might be advisable to drain and flush again with a refill with whatever ATF you prefer without the Lubegard. Even at that, it might be another several hundred miles before you notice better grip. Your symptoms do suggest that you're getting slippage. And, if that's the case, it just might get worse as the Lubegard permeates further into the clutch facing material.

 

[nhkid]

Ray I hope that is not the case. It was over $200.00 for the flush and the Mobil 1 ATF. I really dont want to pay that again. I took this from their web site:

LUBEGARD® ATF PROTECTANT:
Reduces operating temperature, allowing transmissions to perform more efficiently
Increases thermal & oxidative stability of ATF for stop & go driving, heavy loads & towing
Reduces transmission wear, extends fluid & transmission life
Maximizes over all transmission performance
Helps reduce comeback & warranty problems for shops & mechanics
Insures proper & smooth shifts
Prevents clutch chatter & torque converter shudder
Eliminates objectionable noise (squawks) during shifts
Keeps valves free. Frees stuck valves in valve bodies
Prevents hung governors
Modifies harsh shifts & makes them quicker in duration
Can be used with all ATFs: OEM, Synthetic or Mineral Oil Based
Contains LXE (synthetic esters & synthetics)


I will keep an eye on this for a while longer and see what happens.

 

[Ray H]

I hope you're right, too.

 

[nhkid]

Ray I was thinking that this slipping was due to be 'tricking the computer' by giving it gas just as it was preparing to shift. I will try to nail down exactly when it occurs to see if that is the case.

 

[MolaKule]

Mobil 1 ATF already contains esters, so your Friction Modification may have gone a bit overboard. Did you add lubeguard because of a perceived problem, and did you continue to have this problem after the flush?

When driving aggresively, your transmission will force the engine to rev to higher rpms because you're demanding more power for acceleration. The transmission will also shift harder and more abruptly.

 

[OneQuartLow]

You guys had me sniffing the coffee pot for alcohol:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=24;t=000124#000003

nhkid, I presume you'd like the other one killed?

David

 

[nhkid]

Yea David, I posted it in the wrong place.

As far as adding the Lubegard I did this in an attempt to quiet down a torque converter chatter noise. I do think it has worked to some degree but I don's think that it has eliminated it all together. I drove about 60 miles today and everything was fine shifting wise and I did not hear the torque converter chatter at all. (fingers crossed) That noise by the way sounds like I am running over rumble strips on the highway except it is not as loud and it occurs with the transmission shifts into overdrive at about 37mph up to about 48 mph or so.

 

[DEWFPO]

I agree with 59 Vetteman. Some vehicles have adaptive transmissions. Since the transmissions are all electronically controlled (by solenoids) the TCM pays attention to your driving style and then supposedly makes the trans shift more to your personal style. I have never liked this feature on the 2 Volvos we own (especially when there's more than one driver of the vehicle). The TCM thinks it is smarter than the driver and no one has told it otherwise.

You have changed the parameters of your trans by using the Lubguard and the M1. Disconnect the battery to reset the TCM. It can't hurt and doesn't cost a penny.

If it does have an adaptive feature the transmission will shift a little "differently" for the first 100 miles or so (using default parameters) until it has enough data to modify it.

 

[nhkid]

vetteman and dewfpo,

I disconnected the battery and left it for about an hour and then hooked it back up. When I leave work tonight I will see what happens.

Thanks

 

[Mike_dup1]

It may be the additve causing the problem even though they said its compatiable.


I have used ATF in several of my trucks dating back to 1979 model C20 Cehvy custom van and never once noticed any problem. My 1996 truck which I sold to a good friend now has 95,000+ miles on synthetic ATF and still going strong plowing snow.

 

[Bio-T]

I may get flamed off the board for this comment. But in order for a transmission fluid to carry the rating of Dexron III, that fluid must meet the same coefficient of friction whether syn or dino. It has to meet a window.
Now with adding the FM, as has been mentioned, you are now outside of this parameter window. Nothing wrong with the Mobil I transmission fluid. In fact it is a top choice along with Amsoil in the Synthetic arena.

One thing that I would do us unhook the battery. Then turn the headlight switch on. Leave it for 20 min. and turn off the headlight switch and reconnect the battery. Reset your computer and then in a couple days it will relearn your new driving parameters. Worth a try. I have fixed more than one problem this way on GM and Fords.

[ March 10, 2003, 01:13 PM: Message edited by: 59 Vetteman ]

 

[unDummy]

Not sure how "adaptive" the GM transmission is but a total ECU reset could help. Also, some ECU's don't reset with the battery disconnected. Not sure how GM does it.
I would also check with the dealer for transmissions TSBs etc. The automakers lately have had a number of TSBs on just about every transmission out there. Start with alldata.com!

Get a shift kit installed. I little extra line pressure does wonders!

If there are no factory updates to the VB, for your next flush stick with Mobil 1 ATF without any additives.