Slant 6 doesn’t go back in

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Octavio Garcia

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I have a 1969 Dodge Dart with a Slant 6. I ended up getting another slant 6 from a 1970 Duster.

I noticed a few things changed comparing the two torque converters.

Any help and ideas can help. I tried installing the engine a few times with no luck.

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Did you spin the torque converter into the transmission to make sure it was fully seated ALL the way back?

They can be stubborn critters at times.
 
Not enough info, and or pictures. There is a difference in the crank pocket/converter nub/input shaft between 1967 and 1968. If the years of the engines/trans are really as stated, that should not be the problem. There is also a difference between the 904 and 727 converters. With the vehicles listed, they should both be 904 units.
What is the exact problem? You mention the converters having differences. I can't tell by the pictures. What do you see as being different?
Also as stated it is possible the converter was not fully seated in the trans
 
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Not enough info, and or pictures. There is a difference in the crank pocket/converter nub/input shaft between 1967 and 1968. If the years of the engines/trans are really as stated, that should not be the problem. There is also a difference between the 904 and 727 converters. With the vehicles listed, they should both be 904 units.
What is the exact problem? You mention the converters having differences. I can't tell by the pictures. What do you see as being different?
Also as stated it is possible the converter was not fully seated in the trans


The issue is the torque converter boss. My original torque converter on my 69 Dart doesn’t fit the engine I got from a 1970 Duster.

Mine is too big.

The red torque converter fit in nice but doesn’t go in smoothly into the transmission compartment to my original one with the oversized
 
You have a converter/engine mismatch. But both setups should be the same, from the factory. Is the red converter (lower picture) the one from the 1970 duster?
 
well then that trans setup was in something else before it wound up in that 70 duster. the red converter is older than either of the vehicles you mentioned. the blue converter is 68-up, red is 67 or older. this is something I learned the hard way too, when I went to put a 63 engine into an 80 Aspen.
 
well then that trans setup was in something else before it wound up in that 70 duster. the red converter is older than either of the vehicles you mentioned. the blue converter is 68-up, red is 67 or older. this is something I learned the hard way too, when I went to put a 63 engine into an 80 Aspen.

really so the trans in my 69 Dart newer than my brothers trans on his 70 Duster?
 
This is getting confusing. What is your brother using for an engine in the 70 Duster?
If he is using the trans that was behind your engine, and his engine is 1968 or later, he will have the opposite problem. The hole in the crank will be larger then the snout on the converter, and the converter will not be supported. If you have his converter, what is he using for a converter? If he has no engine in the Duster, get the trans from the duster (that was behind the engine you just put in your car), and use that trans, and the red converter.
 
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nice looking Duster why pull the engine out of that? I wish I could find a Duster in any kind of decent condition around here.....
 
This is getting confusing. What is your brother using for an engine in the 70 Duster?
If he is using the trans that was behind your engine, and his engine is 1968 or later, he will have the opposite problem. The hole in the crank will be larger then the snout on the converter, and the converter will not be supported. If you have his converter, what is he using for a converter? If he has no engine in the Duster, get the trans from the duster (that was behind the engine you just put in your car), and use that trans, and the red converter.
He’s not using the trans and suggested on using the transmission just like you did.
I was hoping I could get another torque converter and call it a day
 
Not sure anyone explained...........the crankshaft register was made larger around 68ish? So with an early crankshaft you MUST have an early converter, or one (somewhat expensive) specially made with the early, small snout. Depending on your situation/ engine combo, you could consider finding a later crankshaft, engine, or somewhat bad engine cheap to get the later crankshaft.

"The other way around" that is, putting an early (small) converter snout into a later, larger crank register, there used to be a bushing ring you could buy for that. Those would not be too difficult to build........a lathe.
 
It appears the 1970 Duster had a 1966-67 engine and matching transmission. Try reading the casting# on the block and compare to a list floating around on this site.

Haven't done it, but re your question of using the red torque converter (smaller snout, 1967-) in the later transmission (1968+), I have read that can be done only if you replace the 1st assembly of transmission guts (input shaft, maybe 1st drum, maybe oil pump). I think it doesn't slide in because the #splines on the input shaft differ.

It might be easier to get an earlier transmission. If so, I think you need 1966-68, since 1965 had a cable shift and different output. The speedometer cables might also vary. Problem is I rarely see 1960-80 Mopar today in any junkyards in California. Even my 1985 M-B 300D is getting rare. Indeed, I am visiting SoCal currently and was looking for parts while here. Looks like Ecology was bought by LKQ. They have a web search, but you must search each of their yards individually. In NorCal, the row52 site searches all yards, which are mostly owned by PicNPull (Snhietzer Steel) now.
 
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Gotcha. Thanks for the information. I’m switching the trans as we speak.

now my issue is my brake booster. Is there a plate between the master cylinder and the brake booster?
 
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Gotcha. Thanks for the information. I’m switching the trans as we speak.

now my issue is my brake booster. Is there a plate between the master cylinder and the brake booster?

attached is a picture that shows my power brake booster. It does not have a separate plate between it and the master cylinder, the master cylinder has a rectangular mounting area however.
 
... now my issue is my brake booster. Is there a plate between the master cylinder and the brake booster?
I vaguely remember a thick aluminum plate on one of my Mopars. It had a slot at the bottom to drain any brake fluid that leaks past the MC piston. It must have been on my 1965 C-body or a 1974 Dart junkyard booster setup I had, since the only boosters I had. My 3 old Mopars now have different brake setups, all with newer aluminum 2-hole MC's.

In my newer cars (1984 M-B, 1996 minivan), the boosters use a vacuum seal between their body and the MC, to allow a thinner pancake booster, so they don't need a drain hole. If the MC piston leaks past, the fluid gets sucked into the booster to cause other issues.
 
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