Hey guys. Need some help here. This might seem like a silly question but I honestly don't know. With an automatic transmission, is there anything that prevents the engine from turning by hand?

Here's the deal. Last month I bought a 99 suburban to use for towing. The monkeys working on it before me managed to break off the shift selector on the column so I have no idea what gear the trans is actually in. I can go under and manually move the selector fore and aft, but I don't know which position is park (fore or aft?). The engine appears to be locked. I tore it down to the long block today. Removed plugs an had a 1/2 breaker bar on the balancer, couldn't turn it. Crawled under and put a pry bar on the flex plate teeth and still couldn't turn it.

It's my understanding that the parking paw is what locks the wheels, and that's on the output side of the trans. So there should be no way the transmission is preventing the crank from turning, right?

At least up to the long block I don't see anything catastrophic, although there was major wear on the distributor drive gear. That was the only indication of a significant problem so far. Next Saturday will be dropping the pan and pulling the heads to see how badly it's hurt.

 

Another question. I've never been convinced of the superiority of TTY bolts. I believe that anyone who knows what they're doing and properly preps the block will have reliable service out of conventional head and main bolts. You guys see any reason I shouldn't just go with standard bolts rather than TTY?

"I have a torque wrench and I know how to use it!"

 

Personally, I'd rather use a good quality Grade 8 fastener that I can use over and over, torqued to spec. I'm just an old school kind of guy, I guess.

 

Most 99 suburbans will have L31 sbc so you should be able use the standard bolts.

 

Jen,

It sounds like you have an issue with the engine. I would recommend a tear down, nothing in the trans should keep it from rotating.

I typically have to use a strap wrench to hold the pulley when I torque the balancer bolt on just about anything.

I agree the engine in that does not use TTY bolts and they should be installed based on torque and not an angular measurement.

Good Luck, Chris

 

Bent crank...or rod...or cam seized.

 

Jen,

Silver74Vette is correct. Barring mechanical failure or a hydrolocked cylinder, there is nothing that should prevent you from turning the motor over.

On TTY bolts: when we build engines for performance applications we use a rod bolt stretch gauge. The reason is because the amount of stretch that is measured is a far more accurate indicator of the proper load than a torque wrench could ever hope to give. Unfortunately that method is not feasible with head bolts/studs, or mains. So we are left with manufactures doing extensive testing to find proper loading past a base torque figure. This is why companies like ARP a very specific about what lubricant is used during installtion. It makes a huge difference in the torque reading vs. actual loading. Motor oil even (even the best synthetic) will show greater torque readings on a head bolt than ARP assembly lube by as much as 30%. So on a 100ft/lb bolt you would be short of the design recommendation by 30 ft/lbs
​​​lbs ≠.
Hope that helps.

Dan