Transmission oil change questions

[Linville33]

My 87 V10 with the 700r4 is my first vehicle with an automatic. I wanna change the fluid in it because it needs to be done. The fluid is not black but it isn't bright red anymore. I am very mechanically inclined(worked on many vehicles and usually the first person people call. You know how that goes). I was talking to a buddy about changing it and I always thought you had to flush the tranny to change the fluid but he said I could just drop the pan and do it like a normal oil change. Is this true? What about air bubbles? How to burp the system if there is air bubbles? Thanks

Sent from my XT901 using Tapatalk

 

[RetroC10Sport]

Do NOT flush it, especially if it has a lot of miles. You will kill it.

 

[Linville33]

Its got 15000 Haha I was told rolled over once. Would there be a problem with air in the system?

Sent from my XT901 using Tapatalk

 

[HotRodPC]

If you've got 150,000 out of a 700r4, you did good. This 91 Burb I have shows 219,000 on the ticker and the PO claims it's never had a trans rebuilt and he towed an Airstream 31-33ft trailer once a year for vacation too. Of course he drives worse than Grandpa. My gawd this drives slow.

Yeah, at his point I prolly wouldn't flush it and flush out all the **** in it that's holding it together. A pan drop, with new filter probably won't hurt it though.

You can burb any air out by just running it through all the gears with the motor running. All the way down to 1 and back up 3 or 4 times to open all the passages with the manual valve, pausing in each position about a second or 2. After that, just drive it. Any air should be able to burb itself out the vent and any vent passages in the valve body and pump.

 

[Linville33]

OK so just drop the pan and filter and it should drain all out? What's the capacity? I don't have a owners manual with the truck. I was told it rolled once and its at 115xxx. I'm just trying to make this tranny last until I can get a sm465 or other 4 speed manual

Sent from my XT901 using Tapatalk

 

[HotRodPC]

No, it will not all drain out. You'll only be changing about 3-4 quarts. But some blood in it, and a clean filter will do it some good. If it's not in to bad of shape, and only 115,000 you may be OK to flush it. It's currently working good now? And you're sure it's never been rebuilt before?

Reason you don't really want to do a full blown flush on it if it's that old, unless you know it's been maintained in the past, is as it wears the metals, and fibers that wear tend to stick to the sides of the drums and become part of the tolerances and clearances. Now you flush that stuff away and your tolerances just grew and might be to much and just enough to start slipping clutch packs and overheating the trans. Once that happens it's very very short lived, as in 50-100 miles or so. Not always true, but in many cases it is.

Had it been flushed before and the gunk wasn't allowed to build up, then by all means, flush it again and keep the gunk out of it.

 

[Linville33]

I'm not sure if it had been flushed before. I'll just drop the pan and do it that way. I just didn't want it to get air in it and be stranded. As far as I know the tranny is functioning properly. I'm not sure if its causing my stutter in the engine but I think that'd a bad map sensor or a vacuum leak

Sent from my XT901 using Tapatalk

 

[HotRodPC]

Naww, no reason to fear air getting into it. That part is no different than changing motor oil. The trans case is vented in the top of the case, and the valve body and pump both have vent bleed circuits to bleed air out. No worries there.

 

[Linville33]

Alright thanks so its going to be about 4 or 5 quarts to change it?

Sent from my XT901 using Tapatalk

 

[HotRodPC]

Alright thanks so its going to be about 4 or 5 quarts to change it?

Sent from my XT901 using Tapatalk

All depends on how much you get out. I'd go with 3 quarts first. Then run it through all the gears and check it again. Add as needed.

 

[Linville33]

Alright thanks

Sent from my XT901 using Tapatalk