Possible to start motor with transmission out?

[absolvd]

If possible, I need to try to start the engine on my 1998 Explorer (4.0L SOHC V6; automatic) while the transmission is out. About a week ago, a heard a rattling sound coming from the bell housing area. I was sure it was the flex plate or torque converter. I pulled the trans and the flexplate was fine. I had the TC sent out and chacked, and that came back fine as well. I went so far as to have a friend split open the trans thinking it was something in the transmission. That too, was fine. Everything in the engine runs fine, it throws no codes, and the trans shifts fine. If I can start it while the trans is out, I can obviously tell if the sound was actually coming from the engine. Anybody know if this can be done?

 

[budwich]

Me thinks you got the "early stages" of the dreaded "sohc timing issues / rattles".... hence you are probably looking in the wrong place. I don't see why you can't do a "bench test" on your car instead of a real engine bench.

 

[absolvd]

I was hoping that wasn't the case, but I'm beginning to think you're right. What do you mean by bench test?

 

[dogfriend]

I think you could probably get it to start, but I'm not positive. It will throw a ton of codes without the trans in the truck, but I don't see any reason the engine shouldn't run.

 

[BrianDye]

Hm, i dont think it would start...give it a try though fill us in

 

[absolvd]

What I'm struggling with is the switch on the trans that lets the computer know that it's either in park or nuetral. I don't think the computer will let the car start without it being hooked up.

 

[dogfriend]

You could remove the DTR from the trans and plug it into the harness to fool the PCM. However, I'm not responsible for anything bad that happens. You are charting new territory.

 

[CmdrPopNFresh]

yeah you can do that. but you have to have the trans range sensor plugged in and indicating park. a few months ago i had a 08 f350 with some rattling and i pulled the trans back enough to clear the torque converter and left everything hooked up.

as for that shiney new 6.4 diesel....yeah it bent a rod on cylinder 8 with only 50 miles on it......i guess thatll cause a rattling noise!

 

[budwich]

I was hoping that wasn't the case, but I'm beginning to think you're right. What do you mean by bench test?

"Bench testing" is as it implies... running the engine on a "bench". I do believe that this is / can be done as "normal practice" after a rebuild. Anyways, as indicated by others, you will need to have the range sensor input to get the thing to "think" you have your tranny in neutral / park.... and I think that you are "good to go" although there maybe some "unforseen issues" with "no load" but I don't think that's an issue in terms of a short run. I assume that you have maintained all "anchoring" (ie. engine mount connections).

 

[absolvd]

Yes. The engine has not been touched. What about just putting the trans back in without the torque converter?

 

[budwich]

no torque, no trans.... basically, the pictures that I have seen of engines on a bench is that they are just "sitting there". In terms of your "testing", you should readily hear where things (noises) are coming from. Good Luck. You can do a "simple test" just by cranking with the starter and removing the fuel pump relay so your engine is just turning electrically, that way you will have a little "control" to see if things are going to function with gas.

 

[Stevenmccall417]

If possible, I need to try to start the engine on my 1998 Explorer (4.0L SOHC V6; automatic) while the transmission is out. About a week ago, a heard a rattling sound coming from the bell housing area. I was sure it was the flex plate or torque converter. I pulled the trans and the flexplate was fine. I had the TC sent out and chacked, and that came back fine as well. I went so far as to have a friend split open the trans thinking it was something in the transmission. That too, was fine. Everything in the engine runs fine, it throws no codes, and the trans shifts fine. If I can start it while the trans is out, I can obviously tell if the sound was actually coming from the engine. Anybody know if this can be done?

4.0 sohc is notorious for failing timing chain guides. Some even at low miles. The front chain guide is somewhat easy or possible to fix without pulling the heavy motor. But 8-10 times it’s the rear guide. Design flaw. There’s even a possible failure of jack shaft chain guides or on some models for some reason…a balance shaft chain guide. As for starting it…I’m working on that too. I figured as long as the bell housing and starter were on…I could start it to confirm it was running decent again b4 lifting the 150lb trans back into place. Actually the trans isn’t bad…it’s the torque converter that’s heavy. I haven’t tried to start it at the moment. But I may have to take the electric shift module off the side of the trans just to let the ecm know it’s in park.

 

[imp]

Yes. The engine has not been touched. What about just putting the trans back in without the torque converter?

What would be gained? Trans. input shaft stands still, PCM thinks trans is fouled up.

 

[C420sailor]

Zombie thread resurrection

 

[Fix4Dirt]

4.0 sohc is notorious for failing timing chain guides.

wont dispute this, but sometimes they can give good luck too-my OE 98 ones lasted till 300k, i know it aint average, but with some care they can last. ill be honest ive got no clue how the only "internal" stuff ive done to the engine is the front guides, all everything else has been maintainence, the rad being busted by a flying object on the fwy, intake gaskets, and stuff like that. no clue how my 5r55e is still running with only fluid and filter either, and with tow/offroad duty...... so maybe im not an accurate source of info

The front chain guide is somewhat easy or possible to fix without pulling the heavy motor. But 8-10 times it’s the rear guide.

imo the balance shaft tensioner and the primary one is the most likely to break, then the valve cover ones, then the rear, imo. im still pushin OE valve cover and rear tensioners, the primary has been repaired and the balance shaft ones was just thrown in the bin. in other SOHCs ive seen it was usually something in the front and less likely the rear ones that die before. but just my observations however

 

[Josh P]

Hopefully the OP hasn't had to wait 13 years for the information he needs to complete his repair

 

[Fix4Dirt]

Hopefully the OP hasn't had to wait 13 years for the information he needs to complete his repair

shoot didnt even notice that! luckily this time, when this thread posted, i was alive, unlike that other FS thread

 

[410Fortune]

I know this is old but its on top today so
How? no starter with no transmission
SO how?

Must have trans at least in place

 

[imp]

I know this is old but its on top today so
How? no starter with no transmission
SO how?

Must have trans at least in place

Depends on bell housing, if separate part from transmission, trans. not needed. Generally, the starter motor bolts to the bell housing.