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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: team39763 on August 16, 2007, 06:39:08 pm

Title: Truck won't roll in reverse
Post by: team39763 on August 16, 2007, 06:39:08 pm
I was trying to push my truck in reverse a few days ago, and it won't go.  I put the shifter in N,D,3,2,1 and it still wont' go.  The brakes aren't locked up because it still rolls forward.  The only thing that I did to the truck was jack up the truck from the differntial so I could install a new torque converter.  I had just rolled the truck backwards and forward a few hours before that.  Just a few minutes ago, I jacked up the rear and spun a tire to see what it would do.  It spun forward while the other went backwards(I thought posi's rolled the tires in the same direction).  But when I tried to roll it quickly, it would slam to a stop.  Did I ruin the differential by lifting it from the pumpkin?  I noticed the driveshaft doesn't turn when I spin the wheels- is it supposed to?  The torque converter isn't bolted to the flexplate yet(I need new bolts).  What could I have done to cause this.  Thanks.
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 16, 2007, 09:51:08 pm
Posi will not turn opposite while jacked up. You either have an open differential or a problem if you are saying it's a posi. Pull the drums and check the brakes. Pop the meatball cover off and take a peak
Title: Re: Truck won't roll in reverse
Post by: Captkaos on August 16, 2007, 09:52:07 pm
what year truck?  Gov-loc rearends will act that way, or you have an open diff.  Only true way to tell if you have a limited slip is to pull the cover.
You can't ruin it by lifting at the pumpkin.  Does the wheels spin when you turn the driveshaft?
In an open diff, you can spin one wheel and it won't spin the driveshaft, hence open diff.
Title: Re: Truck won't roll in reverse
Post by: Toolmaster on August 16, 2007, 11:04:29 pm
Disconnect the drive shaft at the rear diff.
Check to see if the trans will turn by hand, check the pinion yoke and see if it will turn.
Be sure to use Jack stands and lift the rear end off the ground.
Let us know what you find.   
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 17, 2007, 01:19:34 am
The truck is an 82.  The previous owner said he put a posi from another car or truck.  I've seen it lay down two nice black strips several times. I'll pull the cover in the when in a couple hours and see if anything looks out of place and also do the driveshaft and pinion yoke check.
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 17, 2007, 04:04:13 pm
Ok, I pulled the driveshaft.  The yoke seems to turn both directions freely.  It seems like I have a limited slip unit in there since one tire turns a few rotations then the other kicks in the same direction.  When I lifted the rear, I could turn the driveshaft to make the wheels go forward, but it wouldn't go the opposite direction.  So does that mean a trans problem?
Title: Re: Truck won't roll in reverse
Post by: Lt.Del on August 17, 2007, 05:48:35 pm
you won't hurt the differential by jacking the truck up under the pumpkin.  i do it all the time. 
Title: Re: Truck won't roll in reverse
Post by: Captkaos on August 17, 2007, 06:49:54 pm
When I lifted the rear, I could turn the driveshaft to make the wheels go forward, but it wouldn't go the opposite direction.  So does that mean a trans problem?

It sounds like you had the transmission in drive and not in neutral if you can't turn it in both directions.
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 17, 2007, 08:44:13 pm
I'll go check again in the morning.  I'm gonna feel stupid if that's all it was.  But I'm pretty sure I had it in neutral(it's hard to tell with this ratchet shifter). 
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 23, 2007, 09:43:05 am
I got under the truck to check the converter and it won't move/rotate at all.  So I'm guessing I installed it wrong.  But I did it just like I was told to - should feel 3 seperate engagements while rotating it on.  I'm gonna pull the motor and try again. 
Title: Re: Truck won't roll in reverse
Post by: Captkaos on August 23, 2007, 10:04:54 am
Stupid question, but is it bolted to the flywheel?
When installing it you need to push it on the pump input and spin it slowly while pushing until it "drops" and engages.
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 23, 2007, 10:12:44 am
So basically you replaced your torque converter and now the truck won't move? You unbolted the torque converter from the flexplate and it won't spin? If that's the case you probably broke your pump. You 1st engage the input shaft into the impeller, then the stator onto the stator support and then the hub into the oil pump lugs. I wouldn't pull the engine I'd pull the trans and replace your pump drive gear or at least carefully inspect it.
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 23, 2007, 10:16:27 am
No, I didn't bolt it to the flywheel because I couldn't get it to turn to line up the holes.  I installed it just like what was said - let it drop in and engage while rotating it slowly.  Would lack of trans fluid make it hard to turn?  It had some in it, but I don't know how much.
   Do you really think I broke something this soon?  It hasn't moved but maybe 3 or 4 feet - thats 2 feet forward with driveshaft in and 2 feet in reverse with no driveshaft.  I'm hoping that it's just not seated right. 
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 23, 2007, 09:27:30 pm
if you bolted the trans to the engine block and the converter won't spin you are not engaged on the lugs on the trans oil pump but rather up against it. As you tighten the engine to the transmission you are squashing the converter hub into the pump. The pump drive gear is very weak and this will most likely cause a fracture. You migh get lucky and be able to just reposition it and put it back in but if not it's going to grenade and take out your converter with it. Loosen the bellhousing bolts and see if you can get it to engage the pump.
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 23, 2007, 11:28:25 pm
Well, I hope it's not messed up.  Will I visually see the damage if it is?  With my luck, it probably is broken.  If it is broke, I'm gonna toss the trans and go look for a th400. 
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 24, 2007, 05:08:18 am
This won't really be visible without pulling the trans and popping out the front seal. Just back it off and try to reinstall it. You might get lucky. BTW why did you replace the converter anyway?
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 24, 2007, 09:25:44 am
I replaced the converter because I had a 2600 in there with the 350 that came with this truck.  The previous owner traded me a 3000 when I did my 6.0 swap.  He said he used it in a car that he got rid of earlier and didn't need it anymore.
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 24, 2007, 10:09:50 am
Is it the correct converter for your application? You must have a pretty aggressive cam for that converter
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 24, 2007, 05:28:41 pm
I actually think I need a bigger converter like a 3500+, but I'm no mechanic.  I'm just a beginner who's trying to learn. 
Hey I backed the trans off by less than 1/4" and the converter spins freely.  I forgot to put a little lube in the crank snout before I put the converter on there, would that explain why it didn't seem to want to turn?  When I went to look at it, it almost seemed as if the trans wasn't seated right when I tightened it to the motor. I'm gonna try putting it back together and see if it spins now.
Title: Re: Truck won't roll in reverse
Post by: VileZambonie on August 24, 2007, 09:48:23 pm
I don't understand why you put that converter in there but anyway make sure the converter is fully seated in the pump. Rotate it and push towards the trans. even with the trans bolted to the engine you should have no problem spinning the converter
Title: Re: Truck won't roll in reverse
Post by: team39763 on August 25, 2007, 01:45:44 am
Nelson Performance suggested a 3000 stall when I had this motor in my wife's truck.  The cam is a 226 with 580ish lift.  I liked how my wife's truck drove with the 3000 that we had in there.  I'm running a victor jr intake now, so I was assuming I'd need a higher rpm converter.  I'm gonna pull the motor in a few hours(need to paint the firewall), so I'll make sure to seat the converter just like you said.   
Title: Re: Truck won't roll in reverse
Post by: Captkaos on August 26, 2007, 09:04:30 am
3000 sounds fine for that application.  My brother was using a 3000 in his turbo'd LS I think he moved up a while back, but I didn't keep up.
Title: Re: Truck won't roll in reverse
Post by: 1976Scottsdale on August 27, 2007, 06:07:48 am
When you get the engine out of the way, crawl under the truck and hold the converter up while rotating it.  It will be easy to tell if the converter is all of the way in because you will not even have room to slip a finger between the converter and trans pump.  Then, when you put the engine in, you will probably have to pull the converter towards the engine a bit, don't worry about it, I have to do that with all of mine and they work fine.
Title: Re: Truck won't roll in reverse
Post by: team39763 on September 01, 2007, 09:10:01 am
I've been doing some reading, and it looks like maybe I didn't need that pilot adapter for my swap.  So I'm gonna pull it out and see how it goes.