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Transmission/rear End Service, 265.00 With Problem


Charter Member
SM 2003
Full Member
Mar 3, 2002
Lafayette, LA.
:7:Just brought AV in to dealership Friday before making a trip and had them change rear end fluid because of some of the post where some members have found sludge/metal in housing.
First off, rear end at 29,800 miles was in excellent shape no metals except the fine powdery kind you find on the magnet, no bad and was well pleased. The chuncks looked great, no chips that we could see
The trans service was discussed and the dealer recommended going with the new B and G inline fluid replacement system.
Regular trans service is dropping the pan and changing the filter and adding the 5 qts. you just lost.
I went with their recommendation and let them use the B and G thingy which ties into you trans line at the radiator, the transmission cooler.
It uses your transmission pump to pump out all old fluid and put in 16 qts of new fluid. Did not change the filter. Transmission service not really required till 50,000 if i remember right. Complete flush of entire system.
Leave the dealership and about 1 hour away i notice when i am speeding up slowly and get to about 48-50 i get a terrible shimmy (only way i can describe it) and speedomiter jumps up and down a few miles an hour.
If you give it the gas it will quit, if not it bounces back and forth between gears (4th/OD).
Call the dealer which has always been great and they said well maybe we dislodged something and it is interferring with you speed sensor which controls shifting.
Back to the dealer tomorrow to see whats up and will let you know
Has anyone else done this complete flushing of the entire transmission. Great concept, but the kind of blew my mind when they said i did not need to change the filter till around 50,000. I am planning on them changing it for free in the morning and replacing the 5 qts anyway.
ZEEYA,,,,,,,,,,,,,,,,,,,,, ???
Well the problem has went away. Their idea was that it was probably the additive that was put in and it was causing the percentage slippage to jump a little above average. The additive is something like a slick 50 type that gives better lubrication and according to them the computer had to learn to apply more pressure on shifts.
So far all is well ???
Zeeya...did I understand you correctly when you said the first tranny service isn't until 50,000k...reason being I just reviewed the online gm owners link and they have a 1 year service...I don't recall if this would include any tranny or rear service... :B:
Zeeya, glad it all worked out. I had this process on a Trans Sport a year ago. The guys didn't tighten the outlet hose tight enough :D: what a mess. Took quite a while to get rid of the oil that went every where and the smell. I have been thinking about putting synthetic oil in my Av's tranny.

There may have been some trapped air in the trans/valving/or pick-up tube... Totally flushing a tranny creates a lot of areas that the air can be trapped ... Since you say you didn't drop the filter, the filter inlet was possibly "fluid" locked for a little while ... The explanation they gave about the trans. having to re-learn to apply more pressure, is a little far fetched in my opinion... Not impossible, but it defenitely sounded good! ... The fact that when you applied more throttle, that it went away tells me that it could probably not be a lubricant issue... When you apply excess throttle, the converter clutch actually unlocks, not applies more pressure... I think there was, as I said air trapped somewhere, and when you gave it more gas, you increased fluid pressure, and pushed the trapped air out or to somewhere where it didn't affect drivability ... If it was cold out when they did the fluid change, and the fluid was cold, that could have aggravated it too... There could have even been air circulating through the radiator causing the line pressure to surge too... Who knows ... A good idea when anyone gets a tranny fluid change, especially a full flush, is to park on level ground, set the parking break, and rev the motor at a constant rpm around 2,000 for a few minutes ... Then, re-check the fluid level once you are satisfied it's warm, and all air is purged... The techs should do this as part of the procedure, but you all know how that can go... :)

All my GM tech friends here in AZ recommend a full flush and filter every 50,000, or a partial fluid dump, and filter every 30,000 on the 4L60E...

BTW, the Eaton G80 locking Differential we have in our trucks require a factory-fill gear oil that is rated for 500,000 mile drain intervals ... That's why the manual does not list a drain/fill service ... Pulling the diff cover on new trucks has almost become a thing of the past with the new fluids, and precision diffs. ... also, the fluid that goes in the G80 we have is a Texaco 75W-90 Full Synthetic Gear Oil ... Make sure when you review the lubricant you want to put in, that the spec. sheet for that lube states that it meets GL-5 AND meets the Eaton 500,000 mile drain interval ... If it does, then it meets the GM spec... (and you probably won't be paying almost $30 a qt either!) ... The diffs will take 2 1/4 qts of fluid in a 1500 3.73 rear...

Thanks for the response 11H, i brought it back in at their request as mentioned above about them finding fuel in their transmission oil. O wait i don't think i posted that great one.
I had called them about something else and he said he had left a message on my office phone to call them. Seems they had swapped some oil around when oil supplier came in. Service manager who has always took care of me with Kit gloves said it bothered him about my problem so he sent sample off and it came back showing some fuel contamination.
Needless to say they replaced filter and completely flushed transmission again. The shuddering had gone away before they redid this. After it was all over and on the way home noticed the shuddering again and turned around to get the manager to ride with me. He felt it this time. I had mentioned the air in the oil possibility and they kind of raised their eyebrows......
Had them cut filter open and was very clean with only a slight bit of very small metal content. Was happy with that. Will drive it a few more days to see if it settles out again. The air very well have something to do with it.
Thanks again
zeeya (y)
I made the appointment for Monday....oil change, chassis lube, and change rear diff oil.....surprisingly enough the service tech didn't ask me for any other info in regards to the rear diff....I thought he would have suggested me wait or whatever the case may be.....but nothing..he said no problem....see ya at 0800.....

I report the results on Monday afternoon...I don't expect for them to come back and tell me any news other than they changed it and that's it...pay me.... :B: