I've looked through the threads on this Juice Box forum and want to try to verify my thinking before I go out, spend money and then find out I am wrong. Here's the problem: Just purchased a high mile 88 Chev Suburban, 350/400 4X4. When I test drove the truck, I didn't take it very far as it was rainy and nasty. I did notice that toward the end of the test drive, it felt like the trans was slipping some when I pushed it kind of hard. When I parked the truck, I moved the shifter from Drive to Reverse and noted it took a lot longer than normal to engage reverse. Reverse to Drive was delayed too. When I say a lot, I mean maybe two or three times what is 'normal'. It almost felt like a low fluid issue so I told the lady I would come back the next day, check the fluid level and if adding fluid cured the problem, I'd buy the truck. Jump to the next day. I let the engine idle until it came up to normal operating temp. Checked the fluid and it was actually about 1 1/2 quarts low. Added a quart of trans fluid and that improved things tremendously. It made me confident enough to go ahead and buy the truck. Put some gas in it and went to the freeway on ramp, made the hard right onto the ramp and hit the gas. WHOA!!! Slipping like crazy! No shift up to third and a lazy, slow mushy shift to second. No engine braking at all. Just like shifting to neutral. I got back off the freeway and drove through traffic with the same things happening. Mushy 1-2 shift and no 2-3 shift. Sharp turns, particularly left turns, cause complete slippage, acts like neutral. The FIRST time up through the gears when it is still a little cold, it seems fine, 1-2-3 and right on time. After that, it acts up again. Now, I live up in the hills above Reno and to get home, I have to climb about 1500 feet up a twisty mountain road. The ride home was 'interesting' to say the least. The truck wouldn't even go up my driveway. This morning, I started it up, drove it right into the garage just like nothing was wrong. Fluid is not terrible but definitely shows signs of overheating. I dropped the pan and found what seems to me to be a normal amount of fine silvery gray sludge and some slightly more coarse grains. Nothing really bad and no clutch flakes at all. The pan seems to be the deep one similar to the one pictured by Larry (70GS) as in his car. It has been a LONG time since I pulled the pan on a 400 but the filter seemed to be way loose and hanging down quite a bit more than I expected it to. The retainer bolt was only as tight as would be expected. Another interesting thing was that the filter seemed to be at a very steep angle. I don't know how long the extended pipe Larry talked about is supposed to be. Mine was not very secure and in fact, nearly fell out when I took the filter out. The O-ring was in place. I'm going to put this back together tomorrow, fill the trans and see if things are better. I do have a few questions for the group though. 1. What is the proper length for the extended pipe? 2. Just how loose should the filter be? I could move mine up and down at least 1 - 1 1/2 inches on the end away from the pipe and tilt it side to side quite a bit. Enough that the only thing limiting it was the pipe hitting the side ot the tunnel it fits in. 3. Is there a proper place to put a drain plug into the pan? Any place better than another? 4. If this doesn't fix my slipping problem, what's next? I'd really like to avoid pulling this monster apart. It is a 4X4 and getting all of that crap taken apart is NOT something I am looking forward to, on my cold concrete floor! Thanks Guys and Gals!
It is normal for the filter to be loose. The bolt holding it in is a special collared bolt. The filter should be able to move up and down in relation to fluid level. The filter pipe should fit tightly into the valvebody. It is good practice to use 2 O rings on that end. Coat the O rings with a little vaseline in order to facilitate installation. Make sure the right end of the filter tube goes into the valvebody. If I remember correctly, there is a flat piece, towards one end of the tube that bottoms out on the vavlebody when the tube is fully seated. (It may take a little effort) I don't remember the exact length of the P/U tube but the part # was 8629526 when I bought it a few years back. I would put the drain plug at the rear of the pan. As long as it doesn't hit any part of the valvebody or P/U, you are good. I would check the normal things like modulator, and governor before pulling it out for a rebuild. Good Luck.
Thanks So Much! The existing tube practically fell out of the valve body so perhaps that is part of the problem Larry. The seller had to have known about the problem because the modulator is shiny and not dirty and greasy like the rest of the trans. I think it's the new adjustable style too. One of the first things I checked was the vacuum line to the modulator. The manifold end seemed old, dry and cracked so I fixed that. The modulator end looks to be new. The filter retainer bolt I think is the correct piece. It is a shoulder bolt and it does allow the filter to ride up and down quite a bit. I'll be buttoning this thing back up later today and will post the results. As a just in case, how hard is it to actually rebuild one of these 400's? Engine assembly, chassis assembly, interior, body, etc. I have done. Not with professional results everytime but successfully. Transmissions? I still think they work because of magic. ou: Would a video/good set of instructions and a good kit get me through it with good results? When I say good, I mean trouble free, and a reasonable expectation of a life of 50k miles. This truck will mostly be used in bad (snowy, icy, muddy) conditions so it wouldn't be good to have it crap out when I am driving and make my girlfriend a potential murder suspect if she was driving! :Brow:
Never rebuilt a transmission myself, but if you are adventurous, a good video should help quite a bit. I think I would just remove it and bring it somewhere if I needed the truck. Shop around, rebuilding a 400 should be very reasonable.
Yeeehaaaaa!!!! I picked up a new filter and gasket yesterday plus 6 quarts of Dexron III. I took your suggestion Larry, to use two O-rings on the pipe. :TU: When I installed the pipe I realized that, even though it is marked "CASE" and "FILTER", it will only install one way. There are two small tabs on the filter end that seem to serve two purposes. One is to locate the pipe fore and aft plus side to side. They rest against the inside front of the case and the valve body on the other side. As an experiment, I tried to insert the filter end into the case. With the tabs, you can't install it that far. At any rate, the pipe went MUCH further into the case than it was when I took the pan off. After installing the filter and the retaining bolt, it is much more secure than before. The filter was quite sloppy and now only has a limited amount of room that it moves around. It does move freely, just not the 2+ inches it did before. Bolted the pan back up and put 3 quarts of fluid in it, then started it up. When I brought the truck home, it had this awful whining noise coming from the area under the dust cover for the converter. Noise is gone! I realized that the driver's side exhaust was inside the garage and most of the gases were being blown into the garage. I got in, put it in reverse and BAM! Went right into gear. Let it roll back, then finished filling the trans. It actually took about 6 quarts to fill it. The test drive was glorious! Shifts a tad early but IT SHIFTS all the way to third! NO SLIPPING! Works like it is supposed to! WOOOHOOO!! Thanks Larry, so much for your help and advice. Looks like maybe my 'Pig in a poke' might turn out to be a good deal after all. :beer :bglasses: Now my girlfriend wants to know how soon I can fix the sloppy steering and put new brakes on it!!! ou: I figure at 10 PM, and I don't need it tomorrow, it's quittin' time! Thanks again!
