Author Topic: A518 Overdrive Questions  (Read 138782 times)

Offline Carlwalski

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A518 Overdrive Questions
« on: July 29, 2006 - 08:43:42 PM »

I am thinking about installing a A518 trans in the 'Cuda as I would like an OD gear.

The 'Cuda currently has 3.23 gears in the posi and I would like to step them up to possibly 3.55 or 3.91. I'm thinking 4:10's maybe a little overboard, the 340ci makes roughly 370hp and was apparently built more for hp, than Torque.


Questions:


1) With a stock Slap-Stik shifters shift pattern being: [1] - [2] - [D], how do you shift into OD? Button?

2) How strong are these transmissions? Dependable? What year(s) are best?

3) Where can I buy one (eBay?) and what do they usually go for in brand new/restored condition?

4) Are there shift kits available?

5) My car currently has a 727 haven't double checked this yet as it came from the factory with a 904.
Do the A518 transmissions bolt straight in or require their own flex plates?

6) What's the final OD ratio? 0.69:1 from memory or something close to that.  :clueless:


Cheers,
Carl
 
:cheers:
1970 Dodge Challenger R/T
White, License Plate, 0A-5599
540ci Aluminium Hemi, F.A.S.T EFI
TF-727 Gear Vendor OD, Dana 60




Offline highspeeddirt

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Re: A518 Overdrive Questions
« Reply #1 on: July 29, 2006 - 09:11:36 PM »
NZ,  I can't answer all your questions, but I know that I have an A518 in my truck with a cummins.  As I'm sure you know these cummins are built with some major torque.  Mine has 230,000 miles on it and still going strong.  I've turned the pump up on mine and the tranny still seems to handle the extra power well.  I know of another guy who has turned the pump up on his cummins and is trying to break the A518 in his, as he wants to go with a stick shift.  He hasn't had any luck breaking it, and he hammers on it daily.  Mines a 93 model and his is a 92.
   Hope this helps you out some.
                                                   :cheers: HSD


Butte, MT

Mike

Offline 360 'CUDA

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Re: A518 Overdrive Questions
« Reply #2 on: July 29, 2006 - 09:47:09 PM »
I know my buddy put that in his '73 but he had to trim the tunnel/crossmember to fit it.

Offline gomopar440

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Re: A518 Overdrive Questions
« Reply #3 on: July 29, 2006 - 10:08:18 PM »
Hmmm, I thought the Cumins diesels got a 618? If I remember correctly the 618 is the HD version of the 518. Same exterior but beefed up internals to handle the extra torque from the diesel.

I'll have to look around and try to find where I saw that statement before I'll feel 100% positive about it's correctness though. :clueless:

Offline Carlwalski

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Re: A518 Overdrive Questions
« Reply #4 on: July 29, 2006 - 10:49:14 PM »


Thanks everyone. I see Shelbydogg, thanks for the explanation, well worded.

Do you guys think it's worth it?  :dunno:
Apart from the A518 is there any other option apart from the Gear Vendors and Kiesler Auto units?

3.23 gears are "OK" but I was wanting more bite from take-off. Though, gears sometimes don't effect performance.
I've seen guys swap a 3.23 for a 3.91/4:10's and gain no significant improvement over the 1/4 mile.


 :1zhelp:
1970 Dodge Challenger R/T
White, License Plate, 0A-5599
540ci Aluminium Hemi, F.A.S.T EFI
TF-727 Gear Vendor OD, Dana 60

Offline gomopar440

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Re: A518 Overdrive Questions
« Reply #5 on: July 29, 2006 - 11:05:43 PM »
Ok, I looked around and couldn't find where exactly I had found that info before. Ironically, the source of the info I could find while googling about for the answer is here.  http://www.gearvendors.com/d2wd4s.html

Sorry NZ,  :misbehaving:

Offline highspeeddirt

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Re: A518 Overdrive Questions
« Reply #6 on: July 30, 2006 - 08:07:21 AM »
Ok, I looked around and couldn't find where exactly I had found that info before. Ironically, the source of the info I could find while googling about for the answer is here.  http://www.gearvendors.com/d2wd4s.html

Sorry NZ,  :misbehaving:

   Heres a quote from your link...
There are two common Dodge 4-Speed automatics: The non-lockup 518 and the lockup version designated 618/47RH. The 518 was used prior to computer controls until 1994. Everything '94 and newer has the lockup torque converter (618/47RH).

Mines a 93, so thats why it has the A518.  It shows on the option sticker under my hood A518 with 3.54 gears in the rear.
   The aticle also talks about the final gear in the A518 being too tall and "hunting" (shifting back and forth while under load).  Hmmm?  never expirienced that with mine, it tows a load just fine.  Not to mention,  I think the smart thing to do if your towing a heavy load is to turn off the overdrive, therefore eliminating the "hunting" they are talking about.
   Sorry NZ, didn't mean to go astray here, I just kept rambling.  I know your not gonna be towing a heavy load, that just kinda struck me funny on the GV site.  Especially after hearing of the problems your having with them.  After seeing and hearing what the A518 is capable of, I would definately consider it if I was in your shoes.
                                            :cheers: HSD


Butte, MT

Mike

Offline Carlwalski

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Re: A518 Overdrive Questions
« Reply #7 on: July 30, 2006 - 08:52:28 AM »


Thanks everyone.  :thumbsup:


Though, I know Small Blocks react better to gear change.....I still think 4:10's are too much.
I'll see, with 4.10s and the A518 I'd be cruising a comfy 2200rpm @ 65mph in OD.  :naughty:


So, to cut it down this is what I need to convert, let me know if I'm correct.

 - Look for a A518 Trans
 - Cut the trans cross-member at the top and modify it so it is thinner. (Or just weld in a 1/4" top plate)
 - The bottom trans cross-member maybe able to be dabbed up with a welder.

Do I need a flex plate, what am I missing it seems all to easy with the above list?  :clueless:


Thanks guys.  :cheers:
1970 Dodge Challenger R/T
White, License Plate, 0A-5599
540ci Aluminium Hemi, F.A.S.T EFI
TF-727 Gear Vendor OD, Dana 60

Offline ShelbyDogg

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Re: A518 Overdrive Questions
« Reply #8 on: July 30, 2006 - 09:08:00 AM »
I think I will be able to modify the original trans mount to hold the trans at the proper angle. I went by a friend's house to look for a spare tranny mount so I don't have to cut up my original, but he didn't have the right one. I want to keep my original so I can still go back to a 4-speed if I choose to.

 I will try to fabricate a rod to hook it up factory style first.  Right now, I welded up a little bracket to hold it at the proper angle. This is a temporary bracket.  You will have to build a new lower trans mount. There is a picture of one on THETRANSMISSIONCENTER's website.


 
 That speedo might be a real problem, but Terry (tactransman) says it'll clear if the trans and engine are pushed rearward before tightening the bolts.


I'm going to go for it before I replace my entire floor. I'm going to solve the Slap-Stik problem. I'm cutting out my floor and might go with a 4-speed so I thought I would try to fit the 518 before the rest is cut to document what is needed to make it work. This way, our site members can see how I did it.
I included a picture of the slap-stik linkage for the 518 project.  The part that the others are having problems with is this vertical bar. When the new fatter 518 case is installed, It's width takes up this space where the bar is.   I don't see it as a problem.





After pulling the 904, I modded the 518 case.  This has to be done to clear the stock trans crossmember, I used a cutoff disk to remove it. Another small section has to be removed to clear the shifter rod, pictured farther down.









I then installed it for mock up. I used a bubble level on the a/c compressor's flat spot to know when it was back at it's original height. The 518 is huge compared to the 904.  After getting it installed, I noticed that the speedometer plate, where the speedo plugs in, will be too close to the crossmember. Jacksboy's thread on Moparts with another user that installed one says to push the engine all the back in it's mounts then the speedo will plug in. Another possible fix would be a new GPS speedometer which just came out.  I'll work on the shifter linkage later but it looks like I'll have to be very creative since the hole is now blocked by the trans.












Looks like a little bending of the upper pivot and fabricating a lower mount might just work.  All of the ratios work because you are using the stock linkage and arms.  The arm has to be in the tunnel before you install the trans. The trans needs a slight mod by cutting off  a little piece that's in the way.  The rod at the trans could be straightened out and shortened if needed.  It seems to work. I don't have headers for the mock-up though. I still need to fab up a lower mount.
More pics after I make it.











Okay,  It's done.  It shifts perfect because it is using the stock arm.
 When I bought the junk yard 518,
I took the little bracket in the pic with it.





 I cut it at the bend, cut it to length,


then welded it back together to hold the bottom of the rod.



I bent the bracket a little to hold the rod at a 90 degree angle.








  I haven't decided to keep the 518 or convert it to a 4 speed yet, but I now know it can be done.    The speedometer nut can be mated up by grinding the corner a little. 


« Last Edit: February 22, 2011 - 12:06:48 AM by ShelbyDogg »
Rob

3 E-bodies, Megasquirt-1v3.0, Edelbrock Pro-Flo-1, Holley C950, FAST EZ-EFI; say no to carbs...yes to throttle bodies

My Pace Car restoration thread:
http://www.cuda-challenger.com/cc/index.php?topic=44869.0


Offline 422STROKER

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Re: A518 Overdrive Questions
« Reply #9 on: July 30, 2006 - 09:47:41 AM »
I think you'll have to modify the trans tunnel to fit the thicker bodied 518.  One of the Mopar mags did a swap a few yrs ago and used a chevey tranny mount to aid in clearances  Someone might still have copy?

Good luck

Tom
Tom
12.77 @ 108.87 15" Street Drag radial tires 3.23 gear

Offline EVIL72

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Re: A518 Overdrive Questions
« Reply #10 on: July 30, 2006 - 10:48:01 AM »
NZ here is a link that has a ton of aftermarket HP 518 tranny parts, HP 518 trannys and if you look 2/3rds of the way down the page they tell you what you need to do.
http://www.redrider.us/518_transmission.htm

 The only thing I didn't see is a pic of a modified upper trans tunnel support. From what I've seen they just notch it to clear the trans housing and then weld a plate to close the notch up for added support. At least they posted a pic of the modified trans mount.
 I'm very interested in this mod also as I've got some 4.30 gears just dying to get used :ylsuper:
 I'm just not sure if I want the lock up or non lock up style trans for a street/strip car. I'm thinking the non lockup but I need to talk to some one with more info.
 Good luck and take alot of pics if you do this mod.  :cheers:
ROB
1972 Dodge Challenger 340ci
1970 Pro Street Duster (Under Construction)

Offline tactransman

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Re: A518 Overdrive Questions
« Reply #11 on: July 30, 2006 - 01:47:03 PM »
NZ , I am going to do that to my Challenger. The 518 can handle anything you can dish it.The connector that Rob is referring to is correct.(above and behind the safety neutral switch)
 If you find one with only two pins on the connector it is a non-lock up and you can put a 727 stall converter in it. :thumbsup:

The 618 is for a diesel and V-10. A 518 can be converted to 618 internals except for the extra heavy duty rev band.(the case prevents that)
Non-lock up version is common 1990 to 1991 1/2. (2 connector pins/wires)no pilot on input shaft
Lock up (3 pins/3 wires) pilot on input shaft
Anything after that is hit and miss.(the heavier duty the truck the more common the non-lock up.)
The non-lock up core is hard to find. When I find one it will be rebuilt and be put in my Challenger with 4.30 gears.
Any unit 1996 and later is computer controlled.
A regular flex plate will work with it.
46/47RH is hydraulic shifted '90 -'95
46/47RE is electonic(computer) shifted.'96 and later
46 is the same as a 518
47 is the same as a 618
48RE came out in 2004, it is all by itself (modified HD 47RE)
« Last Edit: July 31, 2006 - 11:54:00 AM by tactransman »
Terry-tactransman 
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Give a man a fish and he eats for a day,teach him to fish and he eats for a lifetime.

Offline tactransman

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Re: A518 Overdrive Questions
« Reply #12 on: July 30, 2006 - 01:50:23 PM »
I'm just not sure if I want the lock up or non lock up style trans for a street/strip car. I'm thinking the non lockup but I need to talk to some one with more info.
 
A lock up converter is more costly and not as strong internally.
Terry-tactransman 
Torqueflite/Automatic Transmission Specialist
Union, Mo.
Give a man a fish and he eats for a day,teach him to fish and he eats for a lifetime.

Offline Carlwalski

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Re: A518 Overdrive Questions
« Reply #13 on: July 30, 2006 - 08:14:50 PM »


Thanks everyone, great input.  :swaying:

TTMan, so you think get a non-lock up?
This will be for a mild-warm street car. I want strength and durability.  :cheers:
1970 Dodge Challenger R/T
White, License Plate, 0A-5599
540ci Aluminium Hemi, F.A.S.T EFI
TF-727 Gear Vendor OD, Dana 60

Offline tactransman

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Re: A518 Overdrive Questions
« Reply #14 on: July 31, 2006 - 04:52:50 AM »
Yes, 3.91 gears too.  Non Lock up cores are harder to find though.
Terry-tactransman 
Torqueflite/Automatic Transmission Specialist
Union, Mo.
Give a man a fish and he eats for a day,teach him to fish and he eats for a lifetime.