dbittle

I have a 1991 pickup with the mechanical speedometer, which is starting to fail. If I have to pull the cluster anyway, is there any reason I can't just grab a later model electronic speedometer cluster and cable at a junkyard, drop in the Marlin Crawler converter at the transfer case and go on about my business as easily as that? My hunch is finding electronic speedometer heads in good shape is going to be easier than finding mechanical ones at this point in time.

2ToyGuy

I'm pretty sure you're trouble may be the speedo cable. That's usually it, anyway. They get old, and "sticky", and you get some interesting effects from it.
There are cable lubrication kits out there as well, but hey, if the first cable lasted this long, I would think a new one would last that long again...
Pretty easy to replace, too. Might be easier than that conversion. I may well be wrong, though.

Just a thought.
Pat☺

dbittle

There is a good chance you are right and the head is still ok. Here is the symptom. For the first few miles after a cold startup, I get an intermittent grinding noise from the dash area accompanied by a drop of a couple of mph from the needle. After a few minutes of driving, the sound goes away. The other symptom is that the needle fluctuates a bit all of the time, which is the classic sign of the cable needing to be lubed. The truck has 228,000 miles so all of the parts in there are far from new. I tried to pull the cable out of its sheath from the transfer case end last night, but it didn't want to come out and I just put it back in place. If I go to the effort of pulling out the cluster, I would hate to put it back together still dilapidated.

2ToyGuy

There's a circlip at the gauge cluster end. Pretty sure both ends, honestly. Makes it harder to try and pull the cable out.

The symptoms you describe are exactly what mine used to do. 320,000 on my pickup. Replaced the cable, all good. It will get worse and worse as time goes on. I strongly suggest trying the cable. Pita pulling the gauge cluster out to get it off that end, but worth the effort. Do NOT touch the speedo mechanics in the cluster. I tried to lube mine, and now it's 5 mph too high all the time. Be very cautious.

Good luck to you!
Pat☺

dbittle

Thank you for that advice. I was in the mindset of dinking around with it to put a bandaid on the problem instead of fixing it properly. After I read your post, I started digging in to find the exact part number of the cable that fits my truck. I have one on its way, and I grabbed a new speedometer assembly to go with it. The one I have, with no tach or trip odometer, is the only version not discontinued. I'm crossing my fingers I can actually get it. I didn't think to get the instrument panel light bulbs, but I will probably order them at the dealer to hopefully make pulling the instrument panel a job I never have to do again.

millball

I took the guts out of a speedometer cable drive from an R1A transfer case and tapped the inner side bore to accept a grease zerk.

It can be screwed into the bottom end of most Toyota speedo cables, and the cable greased without having to get the inner cable out.

dbittle

That brings up a great point and a question I was going to ask. What is the best thing to lubricate the cable with? I used grease on another project, but it wasn't totally successful (speedometer needle still jumped around). I believe some people in other threads have used PB Blaster or similar light oils. They have to periodically re-treat. Would a grease make too much cable drag in cold weather? If the root cause of the needle jumping around is fraying or wear on the inside of the cable sheath somewhere along the length of it, its going to be hard to fix permanently.

millball

I just use a Moly EP #2 grease, but then I live where it's warm.

I have, in the past, used a small funnel caulked with putty, to lube cables with Marvel Mystery Oil, from the top side.

dbittle

Well, it turns out the speedometer is discontinued after all. Looks like the new plan is to deal with the cable and see where that takes me. I’m suspicious of the speedometer because it makes a buzzing noise on cold mornings and I’m doubtful the cable replacement will fix that. Maybe it will though.

millball

Mechanical speedometers are not too sophisticated.

There are many shops that service and overhaul them.

dbittle

Ok, you caught me. Hey that’s plan B. Probably with the tach and trip meter upgrade though.

jazz1

I disconnected speedo cable for a year,,,it got too noisy. Finally replaced cable with one from my parts truck and it is starting to chatter..Never heard any buzzing from the speedometer itself.

dbittle

It buzzes for about the first 5 minutes in cold weather. This truck sat for 8 years so a few little issues are sorta expected I guess.

corax

What part did you lube up? I just replaced the entire cable on my '88 'runner and it was quiet for 2 days. This morning (frigid temps), it got so loud I could barely hear the radio, so I'm fairly sure the speedo itself has something going on inside of it. I'd prefer to repair, rather than replace, my SR5 cluster because it took a bit of soldering and reworking to get the tach to work with the 1UZ VVTi.

2ToyGuy

I lubed the cable by pouring a liquid graphite lube down it. LOTS of it. Until it came out the bottom. It dries after a few minutes, leaving just the graphite in whatever.
I dripped a little into the actual speedo mechanism in the gauge cluster, and spun the mechanism. Used a real small standard screwdriver. I think that's where I messed up the speedo. Now, I just mentally subtract 5 MPH from it's reading. Haven't gotten a ticket yet, anywho.
Pat☺

corax

OK. I took mine apart last night. I removed the speedo gauge from the cluster and disassembled it. In my case, I think the noise was coming from the pilot "pin" between the 2 cups (cable driven magnet, and copper looking piece) - there was a tiny amount of dried out grease in the magnet side. So I used a tooth pick and pushed a bit of grease in every moving part, this morning it was quiet and I could hear the radio again. BUT, the speedo is reading 10mph slower than my actual speed. Since I pulled the needle off to take it apart, I'm thinking I just need to pull it off again and reposition it . . . maybe that'd work for you as well

dbittle

Think I'm going to grab a gauge cluster from the local U-pick lot this weekend and take it apart and give this a try. It sounds like a good idea. That way I at least have my old one to put back in if the job goes bad.

2ToyGuy

I warned you about that!

Pat☺

dbittle

Well, after delays due to my job, a covid quarantine and some bad weather, I made it over to the pick-a-part place today. I found, of course, that the Toyota Pickup they had pulled in a few weeks ago had been picked clean to the point that all I got was a handful of screws. Ah well, there are lots of instrument clusters on car-part and ebay. My biggest question at this point is exactly what in that head unit is making the noise. When it does sound off, it is loud enough that it is hard to hear the radio. Hopefully I can find one semi-local next week.

corax

I think the noise was coming from the pilot "pin" between the 2 cups (cable driven magnet, and copper looking piece), when they start vibrating they act like speakers and get loud. Check out this thread on FaceCrack, there are a couple pics of the 2 pieces I'm talking about

https://www.facebook.com/groups/1470...30598963919664