Grinding Sound

[Chrisman889]

I have a stock 93 Explorer and lately I have been hearing a deep grinding, almost growling sound as I'm driving. Not sure if it's coming from the front or rear. Shifts fine and I just recently replaced the rear differential oil with the correct oil it calls for. I'm thinking front wheel bearings but not sure. Just replaced the driveshaft u-joint so I know it's not that. Anyone have any ideas?

 

[Azzarone]

I would think wheel bearings as well. Had them go twice on my 01, and it made a grinding/humming sound.

 

[Chrisman889]

I ordered some new ones thanks. Although today when I left fork work it wasn't shifting out of first until it warmed up and when it's idling in D it makes a high pitched whistling sound. Best way to describe it is when u wet your finger and run it around a wine glass. But goes away when I'm in park

 

[Maniak]

You may have a bad vacuum modulator on the trans. When the diaphram on that goes bad trans fluid can make it up to the motor. It softens the hose and the hose pops off.

When the hose is off you have a vacuum leak which can sound like a whistle. It can also affect your shifting so I would look into that first.

Also, for the grinding, to check the wheel bearing you can normally just jack on one corner and spin the tire to see if you get grinding. Also, if you get movement by grabbing the tire at 12 & 6 and push/pulling and you get the same movement when grabbing at 9 and 3 then its usually bad/loose wheel bearings..

One other thing.. If your governor goes bad (gets stuck) in the trans it will keep you from shifting out of first.. Its an easy thing to change, just some work to get to it (have to pull the transfer case off if you 4x4).

~Mark

 

[Chrisman889]

Thanks for the info. I'm not quite sure where that hose would be or the vacuum modulater. I read something else about the governor and a spring being stuck somewhere. I will probably take it somewhere since I have no experience with trannys, and probably get told I need an overhaul of the tranny for $2000.

 

[Maniak]

The vacuum modulator is on the outside of the trans, on the passenger side. It has a vacuum line that runs up the back of the motor and comes out on the driver side (back) of the motor.

You will see an vacuum manifold on the driver's side rear of the upper intake. That is where most of your vacuum lines go (including the one from the transmission). Your looking (and feeling) for an open port on that vacuum tree and for a line that came off.

Those are simple fixes you can check/do yourself.

~Mark

 

[Chrisman889]

Awesome information thank you, probably saved me a bunch of money.

 

[429CJ-3X2]

I agree your whistling and shifting problems are probably from a loose vacuum connection on the firewall. My '94 will "sneeze" on cold start up once in a while and blow a vacuum line off the tree on the firewall. I once drove it a few miles with a line off and it wouldn't idle and shifted weird. I have zip ties on all the connections to help them hold better. Some of those vacuum hoses and nipples are hard to see. Just have to feel around.

 

[Chrisman889]

Whereabouts on the firewall? Also I couldn't seem to find the vacuum modulator. Just dropped mine off at the shop today and they said more than likely a gummed up governor but there is a reason why the governor is getting dirty, probably something causing debris. Recommended I get a rebuild for $2200, which is what I expected from a shop. Thing is when it's hot it runs and shifts fine. I will check the cable tonight for any slack.

 

[429CJ-3X2]

Up high next to the brake booster, towards the center of the truck. It's where several vacuum lines connect to the same "tree".

 

[429CJ-3X2]

Sorry, the vacuum tree is attached to the engine just above the driver's side valve cover. The older vehicles had it on the firewall.

My father-in-law is using my Explorer, and he called this morning to say it was running really rough. I was 99% sure it had blown a vacuum line off the tree. Sure enough, a hose and a plug were off. Put them back on and it's running like normal.

 

[Chrisman889]

I checked those, all were connected. Engine runs fine except for some slight ticking.

 

[Chrisman889]

Do you think if I start using Royal Purple oil, it would help with the valve ticking?