speedometer and cruise

[outofcontrol]

Today I decided to attack my spedo problem.

History: the cruise control stopped working on one trip, then the next weekend the spedometer stopped working.

Today: I pulled the cable off the tranny and put my cordless drill on the end of the inner cable to confirm that the cable had broken somewhere, and I was surprised that it was registering speed on the dash.

Notes: the cable comes off the tranny and goes into a little box. (I assume this is some sort of Cruise control part) Then another cable comes out of the box and goes to the dash.

Question: Can I assume that the problem is in the tranny? or is there some function that happens in the CC box that would inturrupt the "signal" when there is vacuume?

I know it sounds paranoid, but I want to bounce this idea off someone else before I start diving into the tranny.

Thanks in Advance!!

-KM

[Fyrzowt]

I'm not familiar with that particular system, but I would not head straight for the tranny.
Two causes come to mind, somewhat related. There is a good chance that a plastic gear has stripped, either where the cable enteres the tranny, (usually an easy fix) or you may have a gear in the C/C unit stripped.
I would remove the cable at the tranny and try the drill procedure again, to check connectivity through the C/C unit.

Edit: after re-reading your post, I see this is where you started. Check the plastic gear inside the tranny where the cable attaches. After the cable is off, you should be able to pull the gear straight out. May have to carefully use needle nose plyers.

[maxandgeorgia]

Hmm, and I thought this was going to be about swimsuits and the Bahamas (I'll be serious now. Sorry.) ~G

[overlander63]

IIRC, there is one or two small bolts holding a small housing in the tailshaft of the transmission where the speedometer cable goes. When you undo it/them, you can wiggle the housing out, then remove the driven gear. Note the color, it is important that you get the same color gear to go back in, or else the speedometer/odometer may not read correctly. While you have the gear out, look carefully into the hole where the gear goes. There is another gear inside, also plastic, and if it is damaged you should take the moho to a repair shop to have that replaced (put it back together before driving). AIf nothing seems worn or broken, it is possible there is a problem at the other end of the cable, maybe in the "little box" you found. This may be an adapter a speedometer shop installed to get the speedometer to read accurately. If it is broken, you will need to take it to a speedometer shop for repair.

[outofcontrol]

You guys are good.

I took the speedo drive gear (the green plastic gear in the tranny tailshaft) out - it was easy - and I slipped it over the end of the cable core, and it was obviously stripped out. I had to hunt around, but a speedo shop happened to have a box of used ones. I'm pretty sure that was the problem. Ever since I got this MH the speedometer has made noise, and I bet the dry cable was providing enough resistance that it wore out the speedo drive gear. While I was at it I also removed all of the cables and pulled the cores out and fully greased them.

Here's my theory on why the CC went out just before the speedo went out: As the speedo drive started to slip on the cable, it was enough to make the CC shut down with the inconsistant spinning of the core. Soon thereafter it totally stripped and stopped spinning altogether.

No test drive yet, but as soon as I can move a truck blocking the MH, I'll give y'all a report.

I just noticed that I titled this post "spedo" - nice.

-Kevin

[outofcontrol]

Test drive: speedo works, CC doesn't.

I only got up to 40mph to test it (rush hour) but I think it used to work down to 30 or 35.

-Kevin

[safari57]

Having the speedo working is a big step forward. At least you are legal now. It will be interesting to learn whathe cruise problem is. I had an 82 Chev truck and the cruise on it would not work under 50mph. Other cars I've had worked from about 35 as you mentioned. Good luck and keep us posted.

Check out post #5 on the thread noted beloe - it may be relevant to your problem

454 engine vss
Barry

[overlander63]

The cruise problem could be a blown fuse, or maybe a bad brakelight switch. It could be more, but this is the simplest thing (and the cheapest).

[wheel interested]

Originally Posted by maxandgeorgia

Hmm, and I thought this was going to be about swimsuits and the Bahamas (I'll be serious now. Sorry.) ~G

Drats! Me too, what a tease! We jumped in here fast enough eh Georgia?

[maxandgeorgia]

That's right, Carol. I see I wasn't the only one with a funny bone about this ~G

[GlenCoombe]

Originally Posted by safari57

Having the speedo working is a big step forward. At least you are legal now.
Barry

Huh? What? You mean you've actually got to have a "working" speedo? How are they gonna check that? If a cop asks you "is everything working?" You have to reply, "yes, sir." Never offer to give them a ride to prove it.

I think you've got to have lights, (outside) brakes, and a horn. Oh, and in some states you've got to pass emissions. If you pass the tailpipe sniffer they never look inside the engine bay....

I'm sure you all will correct me if I'm wrong.

[Robfike]

Check to see if you have vacuum at the cruise actuator unit on top of the engine. I had some cruise problems and found that my problem was the loss of vacuum at the actuator. The original vacuum entrance step was screwed up and would leak off enough vacuum to keep the cruise from working.
You will have to drive with the engine cover off to do the check.
Good luck, Rob

[safari57]

Hey Glen

As a driver frequently of mostly vintage cars the lack of a speedometer has never stopped me from from driving (in some cases for a long period of time) but it is certainly nice to have one working again when that happens. It just feels right. And I hate tickets because they suck good money out of my pocket that could have bought something else (like a new speedo cable) with that hard earned money. So, you are right, working lights, brakes and even glass are all the critical stuff that are visible and if missing draws official attention, but it just works out sometimes that you either don't have that pace car in front of you, or the pacer car driver turns out to be a wing nut going too fast and thus so are you. Not that that has ever happened either or at least that I'll admit in writing on a forum my wife might read.

Barry

[outofcontrol]

Legal??? that's the last of my concerns

I really don't need the speedo, and the next time it stops working I might just put some tape over it and write "SLOW". I just like to know if I need to put on the hazards because I'm going 15mph under.

Yes, it is nice to know my speed, and I guess I'm legal now, but I'd take functioning CC over functioning spedo any day.

1. brake switch - pretty sure it works because the brake lights work, but I'll check to see if that signal is getting to the CC box.
2. Fuse - that's easy to check, thanks.
3. vacuum lines - there are so many of them, and they all look like they leak, I'm suprised any of the vacuum stuff works. I might just replace all of it if it turns out to be a vacumm leak. There's a diaphram hooked to the throttle linkage that looks 30 years old....ok 26 years old, I'm sure this is the dealie bob that pushes on the throttle.

Can't I lift the rear axle to do the testing? sounds dangerous but I've done it with cars and stuff. What if I just lift one rear dual off the ground and block the other three corners?

I have a feeling my wife is going to tire quickly of driving around testing the CC.

Thanks for all your help you guys!
BTW, the test drive was fun - I've been starting the coach 1x a month since it's been sitting for the winter, but I felt like an actual drive was better for her. Scrapes all that rust off the rotors n stuff.

-Kevin

[overlander63]

Originally Posted by outofcontrol

Can't I lift the rear axle to do the testing? sounds dangerous but I've done it with cars and stuff. What if I just lift one rear dual off the ground and block the other three corners?


-Kevin

No!
I won't go into the physics involved, but your rear tire/wheel assemblies weigh almost 250 pounds on each side, including the brake parts. I would not want that much weight spinning wildly (50 mph is hundreds of RPM, anything could fly apart) just off the ground.
The rear axle will not like only one wheel spinning, the spider gears will be howling, and the truck will try to move forward, even if it is not limited slip, which you will not know for sure without serious investigation. I doubt it is, but am not sure enough to risk the truck getting away from you and flying off jackstands, causing a good bit of damage. So, no to lifting both sides up, and definitely no to just one wheel.

[outofcontrol]

Thank you voice of reason.

I don't think the coach would go screeching out of my driveway, but I'm sure if the wheels were turning at 50mph if they hit the ground, something would give.

So how does one test/trouble shoot CC without actually going out on the highway?

Can I undo the driveline? Should I simulate the speedo drive with a drill on the cable?

I guess I'm getting ahead of myself, I haven't even checked the CC unit yet.

This weekend!

[bobchevy89]

Originally Posted by outofcontrol

Can I undo the driveline? Should I simulate the speedo drive with a drill on the cable?

I guess I'm getting ahead of myself, I haven't even checked the CC unit yet.

This weekend!

undo the drive line and you'll be cleaning up tranny fluid for a long time.try to replace the vac line off the diafram .9 out of 10 times it will work.mine did.

Bob

[GlenCoombe]

Kevin, you need a volunteer to drive while you fiddle. Your wife could do this or you might enlist the aid of a friend.
Glad to hear you've abandoned the up in the air rear wheel(s) accident looking for a place to happen idea....
Drive line dynos even though they are run on rollers actually chain the chassis down to prevent accidental runaways.
I'd start at the vaccum level and work outward....