Drive line angle help

[Tirekickertoo]

Hello,
I wanted the advice of the group on drive line or drive shaft / drive line angles. There is a ton of descriptions and methods on the internet either in forms or youtube videos. To be honest some of the conversations confuse the topic quite a bit. Here's the project I'm working on. I own a non-numbers matching 1970 Challenger that had a 727 automatic transmission in it when purchased used years ago. This summer I developed transmission issues losing third gear. I pulled the tranny and installed a A518 overdrive transmission that was pulled from a working vehicle a while back. Due to the size of the overdrive/tail end area of this transmission and hitting the tunnel, I was unable to get it as level as I would have liked. I am measuring 5 degrees down from the transmission/splined end. I also measured the axle pinion and that reads 1 degree down. Because of the size/length of the A518 transmission, I had a new drive shaft made by FleetPride including new U-joints. The Techs there said not to exceed 1.5 degrees for drive line angle. I've read on the internet that some original Mopar specs were as much as 6 degrees! I've also read that the rear axle will pivot up under hard acceleration. This car is used as a street car/cruiser. Base on the information given, (transmission/splined end 5 degree down and the axle pinion 1 degree down) do I need to shim/raise the rear pinion at the axle perches? If so, what degree shims would be acceptable?

Thank you,

Tirekickertoo

 

[Cudakiller70]

Can you raise motor/trans at all? To get to a 3 degree angle?
With your pinion down at 1 degree you could be fine with a 3 degree motor/trans down. That gives you a 4 degree difference, that’s usually max, but every car is a little different.
So if your motor/trans is 3 down and pinion is down 1 degree, axle wind up could put it 3 degrees up. Then pinion and motor/trans angles are parallel as shown in picture a below.

 

[Steve340]

Do you have a driveline vibration?

 

[DrEamer]

Tirekickertoo

I do have a couple of questions about your conversion to the 518, since I plan on doing it myself. First, what crossmember did you use, I know there is one available, or did you make your own. Also, did you notch the tailshaft housing to help gain clearance into the tunnel? I know everyone that I have seen has had to cut some of the fin/ bracing off to make it work.

 

[Tirekickertoo]

Can you raise motor/trans at all? To get to a 3 degree angle?
With your pinion down at 1 degree you could be fine with a 3 degree motor/trans down. That gives you a 4 degree difference, that’s usually max, but every car is a little different.
So if your motor/trans is 3 down and pinion is down 1 degree, axle wind up could put it 3 degrees up. Then pinion and motor/trans angles are parallel as shown in picture a below.



View attachment 52350

Can you raise motor/trans at all? To get to a 3 degree angle?
With your pinion down at 1 degree you could be fine with a 3 degree motor/trans down. That gives you a 4 degree difference, that’s usually max, but every car is a little different.
So if your motor/trans is 3 down and pinion is down 1 degree, axle wind up could put it 3 degrees up. Then pinion and motor/trans angles are parallel as shown in picture a below.



View attachment 52350

Hi Cudakiller70,
Thank you for the reply. Unfortunately I am unable to raise the engine/transmission any higher. Due to the size of the transmission overdrive unit, I am almost touching the tunnel/floor pan. 5 degrees down at the transmission end is the best that I can get. Any adjustment will have to be made at the rear axle.

Tirekickertoo

 

[Tirekickertoo]

Do you have a driveline vibration?

Hi Steve340,
Driveline vibration is unknown at this time. Based on the angles / measurements, it appears that I will have problems. I will be ready for a road test very soon.

 

[Tirekickertoo]

I do have a couple of questions about your conversion to the 518, since I plan on doing it myself. First, what crossmember did you use, I know there is one available, or did you make your own. Also, did you notch the tailshaft housing to help gain clearance into the tunnel? I know everyone that I have seen has had to cut some of the fin/ bracing off to make it work.

Hi DrEamer,
The crossmember I purchased from US Car tool. I don't believe they advertise it on their webpage. You will have to call them. They did a very nice job building the crossmember at a decent price. I did knotch the tailshaft housing. There is an older post on the internet by 360Fish. He did a nice job showing you where to cut the fin/bracing. Before I dove into the transmission upgrade, I spent time on the internet reading all I could about it. When I have more time, I will share my transmission swap experience with you.

Regards,

Tirekickertoo

 

[Cudakiller70]

Ok then, I would put rear pinion up 1-2 degrees up. Should get it close to parallel

 

[Cudakiller70]

I can’t find it, but I thought there was a front motor mount that is a lower or thinner profile which could help level out motor/trans angle.
Interested in trans swap info also. Thanks

 

[moparleo]

Moparts on the Web - Main Index

 

[Cudakiller70]

Another good one
Setting Pinion Angle - Quality Body Shop Drivetrain

 

[Tirekickertoo]

Ok then, I would put rear pinion up 1-2 degrees up. Should get it close to parallel

Thank you Cudakiller70, I appreciate the knowledge and help.

Tirekickertoo

 

[Tirekickertoo]

I can’t find it, but I thought there was a front motor mount that is a lower or thinner profile which could help level out motor/trans angle.
Interested in trans swap info also. Thanks

Hi Cudakiller70. Huh, I never heard of low profile motor mounts? Good idea! A couple years ago I installed new motor mounts from Schumackers Creative Services. At the time, I didn't know this type of mount existed. If interested, please read my reply to DrEamer earlier in this thread. This trans swap has been done and well documented years ago by 360Fish. I will add my two cents since I recently completed this task.

Tirekickertoo

 

[Cudakiller70]

Probably posted here before, just in case for others searching for driveline info

 

[Tirekickertoo]

Hi DrEamer,
The crossmember I purchased from US Car tool. I don't believe they advertise it on their webpage. You will have to call them. They did a very nice job building the crossmember at a decent price. I did knotch the tailshaft housing. There is an older post on the internet by 360Fish. He did a nice job showing you where to cut the fin/bracing. Before I dove into the transmission upgrade, I spent time on the internet reading all I could about it. When I have more time, I will share my transmission swap experience with you.

Regards,

Tirekickertoo

Hi DrEamer,
Here is my account of the 727 to A518 automatic transmission swap. Again, the best information I have found so far on the internet was posted years ago by 360Fish. This is just my two cents...

Finding the correct A518 transmission: I believe Chrysler made the A518 (46RH) overdrive transmissions from around 1988 to 1995. This at least is the information I read about in finding a donor vehicle. I believe in mid 1995, the transmissions became computer controlled also known as the 46RE. Stay away from the electronics. I was told that it is a headache that you do not want. My donor vehicle was a 1991 Dodge D250 3/4 ton pickup truck that the frame had rotted away. I happened to find the truck on Craigslist. The truck had a Dodge 360 engine which wasn't a problem because the engine in my Challenger was changed to a 1974 Dodge 360 before I bought it. I have read that the 360 engines are externally balanced. The A518 transmission torque convertors are also balanced. I guess there's a balancing issue when connecting the A518 overdrive transmission with the 318's or 340's that are internally balanced. Do your research... This wasn't a problem for me. I was switching the transmission from a 360 to a 360. It will also be harder to find a used transmission these days due to the limited production years and not may junk yards /pick and pulls don't keep vehicles that old anymore. Best of luck in the hunt. My donor transmission had overdrive only with a non-locking torque converter. There were A518 transmissions available locking torque convertors. There's a lot of debate on the internet on which one is better. I didn't have many options in finding another transmission at the time due to reasons already mentioned.

Safety: Buy the correct jack stands and hydraulic jacks. I didn't have the most ideal place to do this swap. The floor was not good and I didn't have a lift. I ended up buying four sheets of 3/4" plywood placing them on the floor and butting them together to make a safer work space. I used two 3-ton hydraulic jacks with long reach to raise the front and rear of the car at the same time. With help you can raise the car up evenly in increments. The car will become very unstable and tippy. I used four regular jack stands to stabilize the car from tipping while jacking. I had to raise the car up almost three feet! The standard jack stands will not be tall enough to raise the car this high. Harbor Freight sell 12 ton (huge tractor and implement) jack stands with long reach. I had to buy four of them. Two for the front and two for the rear. It took a while but I was able to jack up the car high enough to swap the transmissions. For additional safety and because I was paranoid, I stacked pallets sections up under different area of the car's unibody. I did this in case something shifted and I wouldn't be crushed to death. Buying the additional hydraulic jack and 12 ton jack stands were over $300.00. Money well spent. No issues at all with the car being up high and it was stable. Take your time jacking up the car and have help if possible. That's all for now, I will write more as soon as I can.

Tirekickertoo

 

[DrEamer]

Tirekickertoo,

I have read the post from 360Fish quite some time ago, and have used it as a guide to the point of where I am at. I recently, like yourself, picked up a complete donor vehicle. In my case it is a 1993 Dodge D250. My 518 is one with the lock up converter, but I also needed an engine, so I will use the 360 Magnum that came with it. The 518 has no forward working gears, therefore I will need to have it rebuilt before it goes in. Honestly, thanks for the information, I'll use it I'm sure.

 

[Tirekickertoo]

Tirekickertoo,

I have read the post from 360Fish quite some time ago, and have used it as a guide to the point of where I am at. I recently, like yourself, picked up a complete donor vehicle. In my case it is a 1993 Dodge D250. My 518 is one with the lock up converter, but I also needed an engine, so I will use the 360 Magnum that came with it. The 518 has no forward working gears, therefore I will need to have it rebuilt before it goes in. Honestly, thanks for the information, I'll use it I'm sure.

Hi DrEamer,
NO problem, I'm happy to help or share advice I have read or experienced. I'm no expert by any means. I'm learning like the rest of us. That's why this forum exists. Anyways, best of luck with the transmission rebuild and engine install. I will continue my story and share some other issues I encountered when installing the A518 overdrive transmission...

Note: I followed 360Fish post to measure, cut, and notch the aluminum transmission tail shaft housing for tunnel/ cross member clearance ahead of time. A small cutoff saw, files and sandpaper is all that I used and did the job on my work bench. Cover all fluid and electrical areas before cutting. Aluminum chips went everywhere!

Borrow or purchase a transmission jack. The job will very difficult or almost impossible to do without one. I purchased one from Harbor Freight that could handle up to 800 pounds. I bought it on sale and had a 20% off coupon. Best deal in town. Removing my old automatic 727 was no big deal. I had to remove the engine oil filter to gain access to one bolt. I also have long tube headers. I had to loosen the drivers side header in order to remover the starter motor. Got my attention real fast when removing the first and last header bolt. These two bolt holes are drilled into the water jacket. So, antifreeze everywhere! Had to stop, put the two exhaust bolts back in and then correctly drain the radiator. I removed the old 727 and compared it with the A518. The transmission bell housings and torque convertor sizes are identical, no issues there. What I had a problem with was the transmission flexplate. There are two different sizes flexplates available. The difference is that the torque converter mounting hole locations are at different diameters. I think one is 12 inch and the other is 10 inch. No a huge deal, I purchased the smaller diameter at my local auto parts store for around $25.00. The Mopar factor service manual also recommends that the flexplate be inspected and changed if any hairline cracks are seen. Torque to spec. when installing on the rear of the crankshaft mount. Note, the flex plates are one direction only. Meaning that it can only be attached on the crankshaft one specific way and direction only. The same thing goes for attaching the flexplate to the torque converter. I took pictures with my phone and used a paint marker to identify the correct flexplate/torque converter mounting holes. The torque converters for the 727 and A518 are NOT interchangeable. If you have to install the torque converter, there are clearance issues to be aware of. I would recommend watching a few youtube videos first as I did. When installing the A518, the tail section of this transmission is a lot heaver than the 727 due to the overdrive gears etc. Be aware of this when installing it under your car. Things could tip real fast. Mounting the transmission bell housing to the engine was no big deal. Having help will save a lot of time and frustration. Torque the bell housing bolts to spec. I aligned my paint marker markings for the transmission flexplate and torque converter for the first bolt. To turn the engine manually I used a large breaker bar, small extension, and socket on the front of the engines harmonic balancer (crank shaft nut) to rotate the engine in a clockwise pattern. Doing this allowed me to gain access to all four flexplate/torque converter mounting bolts. Like 360Fish, I temporally installed a separate bottle jack at the rear of the transmission to prevent sag. The transmission jack will drop over time. That's it for now, more to come.

Tirekickertoo

 

[moparleo]

I'll also post the article from 360fish. Check out the pictures of the modified trans mount.
727 to A518 swap – a novice guide
Mopar Overdrive Transmission Swap - How To - Hot Rod Magazine
https://transmissioncenter.net/shop/727-to-518-transmission-swap-information/

 

[Tirekickertoo]

Hi DrEamer,
NO problem, I'm happy to help or share advice I have read or experienced. I'm no expert by any means. I'm learning like the rest of us. That's why this forum exists. Anyways, best of luck with the transmission rebuild and engine install. I will continue my story and share some other issues I encountered when installing the A518 overdrive transmission...

Note: I followed 360Fish post to measure, cut, and notch the aluminum transmission tail shaft housing for tunnel/ cross member clearance ahead of time. A small cutoff saw, files and sandpaper is all that I used and did the job on my work bench. Cover all fluid and electrical areas before cutting. Aluminum chips went everywhere!

Borrow or purchase a transmission jack. The job will very difficult or almost impossible to do without one. I purchased one from Harbor Freight that could handle up to 800 pounds. I bought it on sale and had a 20% off coupon. Best deal in town. Removing my old automatic 727 was no big deal. I had to remove the engine oil filter to gain access to one bolt. I also have long tube headers. I had to loosen the drivers side header in order to remover the starter motor. Got my attention real fast when removing the first and last header bolt. These two bolt holes are drilled into the water jacket. So, antifreeze everywhere! Had to stop, put the two exhaust bolts back in and then correctly drain the radiator. I removed the old 727 and compared it with the A518. The transmission bell housings and torque convertor sizes are identical, no issues there. What I had a problem with was the transmission flexplate. There are two different sizes flexplates available. The difference is that the torque converter mounting hole locations are at different diameters. I think one is 12 inch and the other is 10 inch. No a huge deal, I purchased the smaller diameter at my local auto parts store for around $25.00. The Mopar factor service manual also recommends that the flexplate be inspected and changed if any hairline cracks are seen. Torque to spec. when installing on the rear of the crankshaft mount. Note, the flex plates are one direction only. Meaning that it can only be attached on the crankshaft one specific way and direction only. The same thing goes for attaching the flexplate to the torque converter. I took pictures with my phone and used a paint marker to identify the correct flexplate/torque converter mounting holes. The torque converters for the 727 and A518 are NOT interchangeable. If you have to install the torque converter, there are clearance issues to be aware of. I would recommend watching a few youtube videos first as I did. When installing the A518, the tail section of this transmission is a lot heaver than the 727 due to the overdrive gears etc. Be aware of this when installing it under your car. Things could tip real fast. Mounting the transmission bell housing to the engine was no big deal. Having help will save a lot of time and frustration. Torque the bell housing bolts to spec. I aligned my paint marker markings for the transmission flexplate and torque converter for the first bolt. To turn the engine manually I used a large breaker bar, small extension, and socket on the front of the engines harmonic balancer (crank shaft nut) to rotate the engine in a clockwise pattern. Doing this allowed me to gain access to all four flexplate/torque converter mounting bolts. Like 360Fish, I temporally installed a separate bottle jack at the rear of the transmission to prevent sag. The transmission jack will drop over time. That's it for now, more to come.

Tirekickertoo

Tirekickertoo,

I have read the post from 360Fish quite some time ago, and have used it as a guide to the point of where I am at. I recently, like yourself, picked up a complete donor vehicle. In my case it is a 1993 Dodge D250. My 518 is one with the lock up converter, but I also needed an engine, so I will use the 360 Magnum that came with it. The 518 has no forward working gears, therefore I will need to have it rebuilt before it goes in. Honestly, thanks for the information, I'll use it I'm sure.

Hi DrEamer,
I read your post above again and wanted to make you aware of a possible issue you may encounter when installing the 1993 360 Magnum engine into your car. Both of our engines were originally built for and installed in pickup trucks. A few years ago I changed my K-frame to a QA1 tubular K-frame. I needed new engine mounts and purchased them from Shumacker Creative Services. When installing the engine, the passenger side engine mount was over 1/2 of an inch off. Couldn't figure it out? I called Shumackers and explained the issue. The guy I spoke with asked if the engine was a truck engine? I said yes it was. He said that was my problem! Mopar cast and ground the engine block mounts differently than the passenger car engine block mounts. The passenger car block boss is ground flat on one side while the pickup truck block boss is ground on the opposite side. If purchasing new engine mounts you need to specify that you are using a truck engine. It will save a lot of headaches. I ended grinding the opposite side of the boss by hand using a regular grinder and a die grinder. When finished, it worked without issue but was frustrating and took extra time. Being a 1993 engine, I'm not sure if Mopar changed the design and had the boss ground like the passenger car blocks? Just wanted to give you the heads up. This only happened on the passenger side engine block boss only.

Tirekickertoo

 

[Tirekickertoo]

Hi DrEamer,
NO problem, I'm happy to help or share advice I have read or experienced. I'm no expert by any means. I'm learning like the rest of us. That's why this forum exists. Anyways, best of luck with the transmission rebuild and engine install. I will continue my story and share some other issues I encountered when installing the A518 overdrive transmission...

Note: I followed 360Fish post to measure, cut, and notch the aluminum transmission tail shaft housing for tunnel/ cross member clearance ahead of time. A small cutoff saw, files and sandpaper is all that I used and did the job on my work bench. Cover all fluid and electrical areas before cutting. Aluminum chips went everywhere!

Borrow or purchase a transmission jack. The job will very difficult or almost impossible to do without one. I purchased one from Harbor Freight that could handle up to 800 pounds. I bought it on sale and had a 20% off coupon. Best deal in town. Removing my old automatic 727 was no big deal. I had to remove the engine oil filter to gain access to one bolt. I also have long tube headers. I had to loosen the drivers side header in order to remover the starter motor. Got my attention real fast when removing the first and last header bolt. These two bolt holes are drilled into the water jacket. So, antifreeze everywhere! Had to stop, put the two exhaust bolts back in and then correctly drain the radiator. I removed the old 727 and compared it with the A518. The transmission bell housings and torque convertor sizes are identical, no issues there. What I had a problem with was the transmission flexplate. There are two different sizes flexplates available. The difference is that the torque converter mounting hole locations are at different diameters. I think one is 12 inch and the other is 10 inch. No a huge deal, I purchased the smaller diameter at my local auto parts store for around $25.00. The Mopar factor service manual also recommends that the flexplate be inspected and changed if any hairline cracks are seen. Torque to spec. when installing on the rear of the crankshaft mount. Note, the flex plates are one direction only. Meaning that it can only be attached on the crankshaft one specific way and direction only. The same thing goes for attaching the flexplate to the torque converter. I took pictures with my phone and used a paint marker to identify the correct flexplate/torque converter mounting holes. The torque converters for the 727 and A518 are NOT interchangeable. If you have to install the torque converter, there are clearance issues to be aware of. I would recommend watching a few youtube videos first as I did. When installing the A518, the tail section of this transmission is a lot heaver than the 727 due to the overdrive gears etc. Be aware of this when installing it under your car. Things could tip real fast. Mounting the transmission bell housing to the engine was no big deal. Having help will save a lot of time and frustration. Torque the bell housing bolts to spec. I aligned my paint marker markings for the transmission flexplate and torque converter for the first bolt. To turn the engine manually I used a large breaker bar, small extension, and socket on the front of the engines harmonic balancer (crank shaft nut) to rotate the engine in a clockwise pattern. Doing this allowed me to gain access to all four flexplate/torque converter mounting bolts. Like 360Fish, I temporally installed a separate bottle jack at the rear of the transmission to prevent sag. The transmission jack will drop over time.