m1009 Transmission Problem

[NCH18]

A quick (kinda) question for you guys. I've searched a good amount and tried what I can but it's time to call on the pros.


I was driving back from the mountains with around 1000 pounds in the back. About 2 hours into the 3 hour trip, while going down a steep decline at around 60mph and giving it very little fuel, the engine just revs up out of control. Pressing the accelerator makes the engine rev higher but I can feel the power's not going to the wheels. I let up and coast to a stop and am surprised that once I get under 20, power's going to the wheels again but it won't leave first. So it's dark and I call AAA and get it towed home. I've been driving it around the land here and there and everything works fine but it won't leave first. I've gone up to 35-40 once just to see if high revs would kick it over and no go.


I read up a little and thought maybe I'd blown out a vacuum line. I checked the vacuum out of the little rubber hose coming out of the modulator in the tranny and sure enough, no vac. So I thought I'd gotten pretty lucky. Replaced all the rubber vacuum lines, repaired those stupid rubber cdr elbows out of the intake that were blown in half (don't know when that happened or if related), replaced the CDR which I've been meaning to do, tested the vacuum pump and replaced the gasket which was in pieces, and replaced the modulator. Anyway, I have no way to test the exact pressure but it's now pulling vacuum throughout the system. Unfortunately, the problem hasn't changed at all. Took it out on the road and it won't leave first. I even put it manually in second and it's still in first...


The truck has (supposedly) only 15k miles (might be 115k) and the transmission has always been rock solid except I always thought reverse was kinda weak. Is it time to take it in to a transmission shop? Any other cheap fixes to try? I have a filter and fluid sitting around I've been meaning to do. Would it be worth changing that or would it just be a waste as it's probably gonna get drained and switched if I have to take it in.


Thanks guys, this place is a huge help.

 

[cliffyp]

Pop the governor cover off and check your governor. A worn/binding/broken governor will prevent up shift. If your vacuum is pulling correctly, the vacuum modulator is working correctly and your governor is fine, then you are probably looking at an internal problem.

 

[NCH18]

thanks cliffy, just what i was looking for. i'm wanting to try everything easy before paying the big bucks.

 

[rtk]

I would check all the basics , but if you have a "weak" reverse , it generally means you have low main line pressure , not a good thing , indicates time to OVERHAUL . Main line pressure is HIGHEST in reverse , it is a basic step in a trans check , bad reverse engagement , low pressure . Have you changed the filter and fluid and how does it look ? I would also drop the pan and take a LOOKIE see to whats in the bottom of the pan , may find some hardware , also not good . good luck

 

[NCH18]

Good info, thanks rtk.

The good news is i pulled the governer and the plastsic gear on it is not only worn down and apple-cored to death but it looks like the plastic on it even melted off somehow in places.

This isn't mine but gives a good visual of what i'm talking about. Let's just say mine makes this one look half way usable. http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=70042&stc=1&d=1076217967

i do agree that the weak reverse points to an issue that i will have to address at some point probably. I've been putting off a filter/fluid change for 6 months now but not any longer. I caught about a quart of fluid when i changed the modulator and it looked great and the level's always been full. I'll be pulling the pan and changing out the fluid/filter as soon as I get a new gear for the governor on there though. And then just crossing my fingers that things will run ok as is for a while.

Any sources on the governor gear, iIs that a common part? I'm assuming I can just buy the little plastic gear and a new gasket, really hope i don't need to replace the whole deal cause the metal all seems to operate fine, looks brand new.

Thanks!

 

[cliffyp]

You should be able to get just the gear. I don't have a source off the top of my head, just google it. You might also try a local trans shop, they might have one and save you shipping fees

 

[rtk]

You should be able to pick up that gear at just about any GM dealer , VERY common problem in GM vehicle's for a LONG time , do your ride a BIG favor and change the filter and fluid ASAP , those little nylon gear parts went somewhere and now would be a good time for a change . The trans pressure might be low because the FILTER is pluged up . bob k

 

[Stonepicker1]

http://www.steelsoldiers.com/showth...outh-Florida-Rebuild&highlight=florida+dually

See post #62 and #63...just fixed mine last week.

 

[NCH18]

thanks a lot guys, glad i asked before bringing it in. i'm gonna call around and see if i can find it locally but worst case i found a kit with the gear, pin, and gasket for around $15 on ebay. pretty excited it's not something more serious (knock on wood).

 

[NCH18]

Just a quick update and request for a bit more assistance. I changed the governer gear and trans fluid/filter. Everything went great and I felt real proud of myself.

While changing things I had the key in the ignition at some point and forgot to take it out. Now I know I've read on here that the key being in the ignition in the off position shouldn't matter but I've drained the batteries before doing that so I know that for whatever reason it drains mine. So I check and my batteries are dead.

So whatever, I hook up a couple trickle chargers and charge both batteries. Test them with multimeter and get 12.9 on one and 13.1 on the other. Still won't crank, won't even try. Everything lights up right, glow plugs cycle but just a click and occasional little electronic squeal from the relay when I turn the key.

I'll load test the batteries tomorrow and start tracing battery current but any ideas in the meantime? I've been doing some searching and I decided to get a read on both sides of the starter relay (did the doghead about a year ago). I got 25.1 on the big bolt side with key off and 9.7 from the little bolts with key in on position. Does this seem right? Should it be more like 25 and 13?

Man, it's just been one thing after another lately. Any insight?

 

[cpf240]

First of all, I don't see how leaving the key in the ignition with the ignition switch in the "off - remove key" position would cause a battery drain. Unless these trucks have some left over wiring for a key-in-ignition-with-door-open-reminder-buzzer or something.

Secondly, I think your correct that the voltage reading on the doghead starter relay is suspect. I'm assuming that was with the key in the crank position. If so, I'm suspecting a dirty/bad connection somewhere, or one battery is not pulling its weight. I'd suggest the usual full charge and load test routine.

Good luck!

 

[NCH18]

It's crazy right? But I've only drained my batteries twice and I've only left the key in twice and they were both at the same times so,... can't be coincidence. I actually came on here the first time to ask but did some searching and somebody else was getting laughed at for asking the same thing so I thought I must be crazy. But I got in the car yesterday, saw the key left in, thought 'oh no', and sure enough dead batteries. Had just cranked fine the day before.

The relay reading was with the key in crank, correct. Seemed to me that if the batteries were low/bad/etc, the voltage would be low on both the 24 and 12v side of the relay but auto electical (and the 09 in particular) is a big annoying mystery to me at the moment. I guess I'll continue the learning process tomorrow. Thanks for the advice.

 

[NCH18]

Alright, I got problems, would love some help or at least a shoulder to cry on. If mods want me to change title/start new thread, that's fine too. Thanks.

Symptoms/Things I've tried:
Batteries load tested fine.
Hooked up 2 cars with 2 sets of jumper cables and no go. I'm declaring the batteries good (less than 1 year old too).
Head lights come on fine and strong
Fuses are all good
I tried using battery cables to make connections between batteries to test cables as seen on old thread on here
Disconnected and cleaned all battery cables
Hit starter and starter solenoid with rubber mallet (will get the real hammer if it keep messing around)
Jumped the starter relay from the Red to Purple wire. All that I got was some sparks and a thunk sound (couldn't tell if it was from the starter relay I was holding or the solenoid under the car)


Some voltage readings:
Front Battery - 13.2
Rear Battery - 13.2
Bus Bar - 26.2
Diamond connection by GP relay - 13.0
Top Bolt on GP relay - 26.0
Pink wire at IP, key cranked - 10.2
Starter Relay:
Large red wire, key on - 25.9
Large purple wire, key cranked - 20.4
Small purple/white wire, key cranked - 10.6

To me it seems that my 12v voltages are low. IP wire and small purple/white wire on starter relay are both well under 12v. However, as I understand it, a problem on the 12v ignition side shouldn't keep the starter from firing when I jumper the 24v side of the starter relay. But I think the fact that the large purple wire on the starter relay is only at 20.4 when I crank it means something. And lastly, the voltage meter plummets the second I try to crank it and the relay clicks, not sure if that's important.

Any help would be awesome, I'm reading TMs and searching the forum pretty much continuously as this is my main form of transportation but it feels good to get my thoughts out there, maybe somebody will . Thanks!

 

[Speddmon]

Just geting a "clunk" when you jump the relay sure sounds like something is bound up to me. Can you rotate the flexplate with a screwdriver or something to verify your torque converter/trans isn't binding things up?

 

[NCH18]

Interesting, thanks. I will go read up on things til I understand what that means (first car I've ever decided to be hands on with). It does seem quite possible that something could be trans related considering this all started after messing with the trans for a week. I thought maybe I'd knocked something loose on the starter while rolling around under there but everything looks tight. Will do as you suggest and get back to you, thanks a lot for the help.

 

[NCH18]

Ok I pulled the bottom cover off the bellhousing and can just barely rotate the flexplate with both hands, that sound right?

I also can see where the starter has a gear with some teeth, should that be engaging the flexplate teeth? It's pretty far from the flexplate at the moment, like 1/4", or does it extend out when the starter's being used and then retract or something?

 

[Stonepicker1]

You said you load tested the batteries...You need to disconnect both batteries and load test each one with a Battery Load Tester. A battery can have a short inside...they will show full voltage until you hit the ing switch. If the batteries pass a load test with a load tester then you may need a new starter.

 

[NCH18]

I see now that it is indeed supposed to extend/retract to engage flextplate. So is it a bad idea to try and crank the truck with the bellhousing bottom cover off and trans fluid lines unhooked (to get cover off) and see if the starter gear does anything?

 

[NCH18]

Ok thanks stonepicker. I'm going into town so I'll bring them in and get them tested more officially (I just used a little hand one). I was under the assumption that if I had both batteries hooked to jumper cables to 2 running cars then it would start even with a bad battery but might be wrong.

 

[NCH18]

Just went out there to pull out the batteries to take into town and thought I'd give it one last try. Started turning over like crazy! SUCCESS! So I guess the flexplate was bound up or something, maybe the torque converter. When I first went under there it took everything I had to budge it about an inch and now after getting the starter to turn over, while hard to spin, I can move it decently. Which makes some sense I guess, it was sending power, couldn't spin the engine and so the the voltage would just drop off. Which might be why all the power readings that involved having the key in the crank position were low while everything else was normal.

Many thanks to everyone, you're all gentleman (/ladies) and scholars in my book!