Need help figuring this out. Have another issue with the Van, this time I think it's a Tranny issue though i'm not quite sure. Now when driving it makes a weird sometimes loud clicking noise. Best way to describe it would be to picture a bicycle with a playing card attached to a spoke, only use several cards instead of one and on both wheels, then drive down a hill really fast. I have ruled out the suspension and rear axle, Had the rear jacked up and ran the engine to spin the rear wheels and see if I could hear a noise, I did not. I realize weight on the axle plays a role so I did another drive test this time I played with the gears a bit, shifting into Overdrive, then back to Regular Drive, 1st, Neutral, etc. Shifting between Reg and OD quiets the noise, putting the van in neutral while it's rolling stops the noise altogether so thats where I ruled out the rear axle. The noise is not present while backing up, sometimes putting it in neutral before putting it in OD or Reg Drive prior to takeoff quiets the noise as well, but that doesn't always work. Seems to be getting worse it used to be only an occasional clunk which I thought might be the suspension since it has seen better days, now this and since it's effected by what gear the tranny is in I don't think it's the suspension. I thought at first it might be a tranny mount since it hasn't been changed in years but I would think if that were the case the noise would be present in all gears, even though I don't think it is the mount the fact it is old is not helping matters. It kind of sounds like it could be the park lock mechanism, I do not know much about Automatic Transmissions this is basically uncharted territory for me in the world of Auto Repair. I can remove a transmission, and install one, as well as hook it up properly but I don't know the first thing about servicing one short of changing the fluid. Vehicle and Transmission Specs: Year: 1985 (Vehicle and Tranny) Transmission Type: Automatic Overdrive (AOD) Mileage: Over 100K don't have an exact # It does have a locking differential, not sure what relevance that is but thought I'd throw it in .
I will list some obvious things that you may or may not have already considered... Exhaust leaks are often only loud under load (in gear) and would quiet right after a shift due to a drop in RPM. Would also be quiet when coasting. Something could be loose and rubbing the driveshaft. When you talk about a 'clunk', it leads me to think of either a U-joint problem, or a bad pinion gear. The U-joint will clunk when you go in and out of gear, as well as when you get on and off the accellerator many times. The rear pinion won't vibrate until the bearing is super shot. It will however cause clunks when going from no-load to load, as well as roar. However the roar of a pinion bearing is not like a worn gear or bad setup. The sound is often higher pitch and might fall into a sound that some might describe as a very intense click or chatter. I'd crawl under the van next time you are around it and tug/shake the drive shaft at the front and rear. Then go beyond the rear joint, to the pinion yoke, and give it a good tug/shake. I had a pinion bearing out so bad on an E350 once that the pinion yoke moved a huge amount. I don't even know how to describe it... I was amazed the van still drove it was so bad. It had transitioned from chatter/high pitch roar, to a roar with vibration. I had let it go for a while, and we use our vans for heavy towing, so it didn't take long to deteriorate. You can also check the brakes. I had a broken E-brake cable connection on one side before, and it clicked when under load. It was brake components loose, and possibly the shoes vibrating due to losing the stabilizing effect of the tension on the cable.
Oh, you might look at the flexplate or lock up converter after all else fails. I don't think I'd look there first without reason, but a cracked flexplate will make all sorts of noises under load. The damage has to be pretty bad from my experience to make much noise without load. Question: Do you have any vibration to go along with the noise?
Axle bearings- jack up, spin wheels to feel for "roughness" in turning. See if you have any play at wheel with van still jacked up. If driven, feel for extra heat in bearing area. U-joints- with van still jacked up, check for play. Jack up by rearend, with jack stands supporting at ride height, check if anything is close along the entire driveshaft. Check back n Good Luck!
Would that van have a 9" or 8.8"? If 8.8" and if axle bearings going out... You have to worry about losing an axle while driving. From what I understand, a clip type rear will let an axle loose if the bearings get to a certain point.
putting the van in neutral while it's rolling stops the noise altogether Check U-joints thoroughly, non serviceable joints (no lube fittings) can become totally rusted inside and not immediately show looseness,being dried out and remaining tight for a while before comng apart .Putting in nuetral when moving and noise goes away lessens the problem areas.
thats backwards. the 8.8 uses a c-clip axle. that retains the axle at the inner most end. the 9" uses a bearing retainede axle. if the axle bearing goes bad on the 9" axle you usually see a huge puddle of gear oil under that tire long before it falls out. an 85 van probly has a 8.8. the first thought i had when the described sound is a exhast leak. you can take a pice of hose and use it like a stethascope and hold one end to your ear and move it all around the exhast manifolds and if you go accross the leak you will hear it. do this when its idleing.
I'm not sure on the rear end size I will check my Service Manual, since it's not a heavy duty setup it is probably an 8.8 Tried the driveshaft trick it is solid as a rock does not wiggle. I forgot to mention I spun the tires manually when I had it jacked up, I put the transmission in Drive and released the E-Brake and turned the wheels as fast as I could didn't hear anything out of the ordinary, but as I noted above with all the weight off the Axle I guess that would be a factor in not hearing anything. It does puzzle me that if it is something in the tranny or Flexplate I would think even jacked up with the wheels spinning and in gear it would still make noise but it only does it when it's on the ground. I did check the Gear Oil Level in the Differential and it could use a changing, seems low too, Oil did not seap out when I loosened the plug which to me seemed kinda odd, I wasn't expecting it to spill out but it should still have seaped a little. When I checked the Differential Oil in the Mav a few years ago it seaped out before I even had the plug loosened 1/2 the way. The Van's Diff Oil seems black definetley been in there a long time I don't recall it ever being changed in the time we've had the Van (Since 1994). I have never done such a job before I have an idea what I need to do though I do know it's nothing like changing the Oil on the engine . U-Joints were the first thing I suspected from the test I did they appear to be fine. It is a two piece driveshaft so I also checked that center area where the two pieces meet and it seems fine as well.. As for the exhaust i'm not sure if there's an exhaust leak I mean I know what those sound like this Van has had them before, doesn't sound anything like that and it doesn't sound like it's coming from any exhaust component. I will still look into it though. Anything to rule out the tranny I do appreciate the replies, I'm just hoping whatever is wrong it's not an arm and a leg to fix.
