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How to get 4.0 and transmission to go together

KirkT

New Member
Joined
Jul 17, 2022
Messages
12
Location
Georgia
I pulled out my original 4.0 after I found pieces of the #3 piston skirt in the oil pan. I bought a reman 4.0 and am having a heck of a time getting the new motor to slide into the bellhousing properly. I did not remove the transmission when I removed the engine and this is my first time attempting something like this. I put on a new clutch and pressure plate and lined it all up with the alignment tool but I can't get the engine to slide on the transmission shift far enough to bolt it up. What am I missing here?
 

Yoda

TJ Enthusiast
Joined
May 5, 2021
Messages
202
Location
MA
I've been there. How close are they from mating? 1/8"...1/2"....2"? I don't remember if the dowel pins are on the transmission side or the engine side but you need to be pretty damn close as far as angles go. You have to line the engine and trans up almost perfectly before it will "clunk". Is your transmission input shaft mating with the clutch? I imagine you'd be an inch or two off if they weren't in alignment. Spin the flywheel by hand with a prybar a bit to try and align it if that's the problem.

The dowels are a pretty precise fit, so if everything isn't aligned perfectly its a big PITA. Feel free to shake the engine or trans when you are trying to get them to mate, sometimes that's all you need. A floor jack under the trans can help line things up too. You can put a good chamfer on the dowel pins too to help things out.
 

Turdworlder

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Mar 2, 2020
Messages
292
Location
Kazakhstan
Been there. It turns out the tales about manual tranny being easir to work on are fake. I used to spend 10 minutes to put on the auto tranny alone using creeper lift. When i swapped the auto to manual i couldnt put on the tranny from first attempt. It turned out that the input shaft was banging the side of pilot bearing after second attempt i slided it into engine mounts. Buckle yourself,op, you gonna sweat alot
 

cpwolf

TJ Enthusiast
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Jun 15, 2020
Messages
900
Location
TEXAS - Cedar Park
Are you alone? Getting it stabbed is first step, then turning the output. When you say you didn’t remove the Trans, does that mean the skid and all are bolted up?

Personally, I had the trans on a Jack and could maneuver it, and turn the output, jiggle it etc. The trans angle held me up, I didn’t have it going in straight enough, I had to step back and cuss randomly in the garage to see that was the problem.

I was also lucky my brother has all kinds of long dowels for this, may be worn making some. Get a bolt really long take off the head. Make sure it will go through the trans hole long enough.
 

Jerry Bransford

TJ Guru Moderator
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Nov 9, 2015
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24,842
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Fleming Island Florida
I had a hard time getting my manual transmission off and back on the engine too. It's usually just the smallest adjustment to the height of the transmission on a jack that is the trick to getting its angle correct so it finally slides into place. Like the smallest possible adjustment to the jack height made all the difference in it being impossible or it going right in.
 

cpwolf

TJ Enthusiast
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Jun 15, 2020
Messages
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TEXAS - Cedar Park
I had a hard time getting my manual transmission off and back on the engine too. It's usually just the smallest adjustment to the height of the transmission on a jack that is the trick to getting its angle correct so it finally slides into place. Like the smallest possible adjustment to the jack height made all the difference in it being impossible or it going right in.

But man…..then when it stabs on….it’s an adrenaline rush! Ha, and for me more cussing, celebratory, but my wife still rolls her eyes, she can hear me out there, ha
 
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machoheadgames

LED turn signal club
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Jan 21, 2021
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1,129
Location
Dallas, TX
I make my own dowel bolts by buying long bolts at Ace, cutting the heads off and grinding a slot into the end. I put them at 3:00 and 9:00 on the motor. Hasn’t failed yet, 1 man install success.

Once you get the transmission up onto the dowels and slide it far enough to know it’s engaged into the clutch, you can use the other bolts to draw it up to the engine. Then you can remove the homemade dowels and put the real bolts in those spots.
 

Jerry Bransford

TJ Guru Moderator
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Nov 9, 2015
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24,842
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Fleming Island Florida
I make my own dowel bolts by buying long bolts at Ace, cutting the heads off and grinding a slot into the end. I put them at 3:00 and 9:00 on the motor. Hasn’t failed yet, 1 man install success.

Once you get the transmission up onto the dowels and slide it far enough to know it’s engaged into the clutch, you can use the other bolts to draw it up to the engine. Then you can remove the homemade dowels and put the real bolts in those spots.
Too bad we can't stop people from trying to use the mounting bolts to pull a stubborn transmission into place. I wonder how many broken/stripped mounting bolt holes have been caused by that big mistake.
 
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CharlesHS

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Mar 10, 2020
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Jacksonville FL, Quezon Philippines
Too bad we can't stop people from trying to use the mounting bolts to pull a stubborn transmission into place. I wonder how many broken/stripped mounting bolt holes have been caused by that big mistake.

I agree....
IF the transmission will not slide into place within 1/8-1/4" then there is something wrong and you need to determine what the problem is....
Drawing the transmission into place with the mounting bolts is not the answer.
 

cpwolf

TJ Enthusiast
Supporting Member
Joined
Jun 15, 2020
Messages
900
Location
TEXAS - Cedar Park
Too bad we can't stop people from trying to use the mounting bolts to pull a stubborn transmission into place. I wonder how many broken/stripped mounting bolt holes have been caused by that big mistake.

Yeah, dowels are a guide, if it doesn’t mate up, gotta keep trying. Pulling with bolts is asking for problems in my experience.
 
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machoheadgames

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Jan 21, 2021
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1,129
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Dallas, TX
Yeah, dowels are a guide, if it doesn’t mate up, gotta keep trying. Pulling with bolts is asking for problems in my experience.

You don't want to just crank on the bolts if you're in no mans land and not engaged to the transmission. If you're on the dowels and the trans input is inside the clutch, then you aren't going to hurt anything. Once you're on the dowels there should be no issues sliding the transmission basically all the way up to the back of the engine anyways.

Where the bolts become a bad idea is when the transmission is just sitting on the jack, won't go into the motor, no dowels guiding it, and people just slap in the bolts and call it good. That is a terrible idea. But that isn't what I said to do.
 

freedom_in_4low

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Sep 26, 2019
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5,488
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Edmond, OK
just gotta work it around until it fits. The tip has to get into the clutch, then it has to get into the pilot bearing on the crank, and the splines have to get in.

Honestly I found it easier to do on my back, benchpressing the transmission in and holding up the tail of it with my knees, so I had complete control over it's orientation and was looking straight up at the input shaft. With a jack I spent much longer trying to get it lined up, and pointed perfectly in line with the crankshaft. But I'm not as young as I used to be, so benchpressing it with my hands and knees isn't as easy as it was when I was 25 and I'm a lot more concerned with dropping a transmission on my face.