Roaring/grinding noise
 

New to here and new to this truck! I have a 91 4cyl 5spd pickup. Rough shape but runs good, 4x4. I have noticed sometimes when letting out on the clutch to take off I hear a roaring/slight grinding sound coming from like under my feet. It is more noticeable when downshifting and releasing the clutch. Any ideas what's going on here? Thanks in advance!

Also the speedo doesn't work I assume it's the speedo cable, went to oreilleys they said it was discontinued. Anyone know where I can get one??

Try Rock Auto.
First i would check to see if that,s the problem.
Welcome to the forum!

Sorry to be so ignorant but how do I check to see? I'm just assuming from the research I've done

Welcome to the forum!

What kind of grinding noise is it? Is it like a mouse chewing on it or more of a "clunk-clunk"? If it's the latter, it's probably not the speedo cable. Does the clutch release smoothly? It could be the throwout bearing, but cross your fingers it's not.

If you want to check out the speedo cable, you have to take out the gauge cluster, pull the cable from the back of the unit and spin it by hand. It should spin rather freely. If it's grinding then that's your culprit.

I don't think the speedometer not working and the grinding/whining are the issue. I believe it is the transmission gears after talking to some people about it, getting fluid changed today so I'm hoping that fixes it. It mainly only does it when you downshift.

Can anyone tell me how to tell if I have a speedo cable or speed sensor? Also where is it located on the tranny? Sorry for all the ignorance lol

Its not ignorance it's called a new experience and a new learning curve, welcome to Yotatech.

Bump.... Pretty sure the grinding is the throw out bearing,truck is very hard to get into first and second gear a lot any ideas? Has new slave and master cyl.

Also how do I tell if I have a speedo cable or speed censor? Thanks in advance!

I dont know if i would call it a grinding noise but when the bearings on my trans were bad it whined really loud in 1st 2nd * 4th and 5th.. (3rd was cool for some reason)
3 days in a trans shop and $914.00 quieted it right up...

if you have the cable, it'll be coming out of your t-case.
as for the grinding, if it sounds like two pieces of flat metal rubbing (like disc brakes with no pad material left) then there's a good chance it's the back of your flywheel hitting the bendix.

It's really more of a loud roaring than grinding, reason I'm thinking it's the throw out bearing other than people telling me it is, is it doesn't do it in 4th gear and I know these transmissions have like a direct drive/ 1to1 ratio kinda deal in 4th. Gonna get someone to check it out this week hopefully.

As for the speedo cable I've been under the truck several times lately and I haven't seen any type of cable down there on the transfer case. Not saying it isn't there but I have looked around and haven't found anything. Where is the speed sensor located at if it has that?

Thanks so much for all the help! Keep it coming!!

The throwout bearing doesn't care what gear you're in - it's ahead of the transmission and independent of gear. If 1st, 2nd, 3rd, and 5th are noisy but 4th is quiet, it's almost certainly in the tranny, probably a countershaft bearing. As you mentioned, in 4th gear the drive is direct (output shaft is locked to the input shaft by a sliding collar), where in all other gears the drive goes through the countershaft.

The speed sensor will be on the output of the transfer case (towards the back). Look for a connector plugged into a part inserted into the transfer case. I seem to remember it being on the driver's side, but don't hold me to that.