silverbullet02

It all started earlier this week, speedometer working intermittently, going down the road, drops to zero and picks back up, sometimes does it for a while, sometimes doesn't. Also noticed that when I hit the brake pedal, the oil and temp gages go up, let off and they go back down. This morning I go out and speedo doesn't work at all...later on today, it started working intermittently, and stopped again, however, this time when I hit the brake pedal, it did the same things, but now the speedo works when I hit the brakes...and the wait to start light is on now too...it's 82 in the shade right now. If you guys have any words of wisdom, I'd greatly appreciate it, never seen anything quite like this and hopefully someone has a clue. Thanks a zillion,

Brian

pind

I could be barking up the wrong end of the dog here, but. (t)

It sounds like you have either a bad ground problem, or a short to ground from your brake light switch.

If I recall, and its been a while. at or near the drivers side, up near the firewall, there is a junction inside the harness where several ground wires come together. I have seen cases where this junction gets corroded, and all kinds of goofy, wonderful, right on, solid, cool and groovy things start to happen. Clean the junction up, solder it properly, and things tend to get all spiffy again.

Otherwise, check to see if the power wire from your brake light switch is rubbed through somewhere, or shorting to ground. Also, you can have trouble with it backfeeding through the fuse block.

This may sound somewhat like the shotgun approach to finding the problem, but hey, its worth a try. Let me know how it goes.

" the flow of electrons within a circuit, is the same as marbles through a garden hose" - 4th year heavy equipment tech instructor.

wannadiesel

Sounds like a grounding issue. Clean all the grounds you can find, maybe run a new one between the cab and frame.

frostie

If all these problems happened at the same time, then I agree about the ground problem. however I have seen this problem with the speedo. It may be electrical or if the yoke nut loosens up it will allow the pulse wheel at the speedo sensor to slip. sometimes there are 2 different problems that all appear to be related but sometimes are not.
Good luck

silverbullet02

Anybody have a diagram of the tranny/speedo gears? I'm gonna try and tear into it when I get home from work today. Drove it to work yesterday morning and drove across base this morning and everything appears to be normal again except the speedo still isn't working...like frostie said, I'm thinking I have a couple different things going on in parallel here...I appreciate the replies,

Brian

Nuttymopar

For the speedo problem. I was able to still purchase from dealer a complete new speedo adapter and connector. Cost a little bit, I forget right now what that was. But mine mostly just died. It was pretty worn inside with the gears have falling apart.

As for electric stuff, I agree, some grounding problem somewhere.

silverbullet02

Well, I found the nut that seems to hold the sending unit onto the tranny to be loose tonight, but nothing. Is there anywhere to find any diagrams so I can see what I've got down there? Thanks,

Brian

frostie

The Yoke nut is behind the U-joint. you have to drop the drive shaft and tighten the large nut on the end of the shaft. If it is loose it will cause the needle on the speedo to drop then jump back up while driving. If that nut is loose it will cause the gear to slip that drives the speedo.
Check it out, good luck

Bill Tomlinson

My speedo started wandering, When I looked at the yoke, the nut and the end of the shaft had snapped off. Had to pull the tranny, replace the whole shaft. Did all my bearings and synchro's. The group here walked me through the issues and the old Getrag works fine again. I sure hope your problem is a ground or something cheap.

silverbullet02

Well, fixed the speedo the other day, ended up being the vss...took the old one apart, worn down too much to really fix, so picked up a new one from local parts store for $51. Never has done that thing when I hit the brake pedal and the gages go nuts again. My volt gage still does some wierd stuff tho, voltage is not consistent at all, even steady state driving down the road, not really sure what's goin on there, but at least everything seems to work at the moment.

Brian