97 Sonoma 4.3L Transmission Fluid (Manual)

DawgTSi · May 4, 2006

OK, I'm posting this for 2 reasons... one, cause I couldn't find anything in the search and maybe sometime in the future someone else will need to find this information, 2 cause I need some qualification to what I think here...

ANYWAYS... 1997 GMC Sonoma 4.3L V-6, 5 speed transmission, 140K miles... there are two allen wrench (size: 5/8) ports on the passenger side of the transmission. One is on bottom, one is on top. The port on the bottom is to drain the fluid, the one on top is to check/fill the fluid. You will need a hand pump to fill the fluid, as it is very difficult to reach.

Here's my question: The last two days, my transmission has been making a loud whining sound, specifically in 2nd gear, and just recently in 4th and 5th as well. So, I pulled the bottom plug out (this was before I realized there was a top one) to check the fluid. As I hastily put the plug back in, I had the pleasure of having tranny fluid leak down all over my hand and arm. The fluid was a dark black color, and had the viscosity of used motor oil. Had I not just taken this out of the transmission, I would have guessed that it WAS very used motor oil. So, am I to believe that healthy transmission fluid is not supposed to be this way? I plan on hitting the dealer tomorrow to get some tranny fluid and replacing what is in there. What is the capacity of the transmission? How many quarts do I need to buy?

Thanks gang, I'll follow up with this after I do the fluid swap.

ChevyTech007 · May 4, 2006

NV1500

Synchro-Mesh Transmission Fluid With Friction Modifier GM P/N 12377916

2.7l

2.9qt

DawgTSi · May 4, 2006

NV1500

Synchro-Mesh Transmission Fluid With Friction Modifier GM P/N 12377916

2.7l

2.9qt

<{POST_SNAPBACK}>

Sweet, and I am right to assume that the viscosity and color of this stuff in my truck is a bad thing, right?

Thanks dude

DawgTSi · May 5, 2006

Well, I changed out the transmission fluid today. The stuff that was in there was nasty as heck. Since changing the tranny fluid, the loud whine has gone away, but I still have a slight grind when going into 4th.

Next, what is the capacity of the rear diff, and can I use the synchromesh fluid in it?

Thanks.