A518 to 47RH swap

gwhammy said:
So is the overdrive on a 518 is the same as the 47rh? I'm thinking of a motor swap down the road and would like to use the 47rh and a 205 transfer case. I've done alot of looking but can't find a solid answer if the 205 can be bolted to a rh.
I'm not sure you can get enough fuel out of the little pump to pull a locked convertor unless you are running some real steep gears. Maybe locked in 2nd but not drive.
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No, the A518 is basically a gas trasnmission, fact is it appears to me that it has a small block bell housing... I also think it has the smaller 6" low/reverse drum, single wrap band, and 12 roller sprag. But then again that's a guess as I've never fully tore one down.

The 205 to 47RH looks to be possible, the one on that 92 has the same 6-bolt flange and the output shafts are supposedly the same (dia. and spline count-wise anyway).

As far as pulling, that's kinda what I was thinking too, I'm not sure what the 205 has for low range, but he has 3.54 gears and plans to run tires in the 33" range... Even if I get him to the 500hp mark, I still don't think he'll be able to pull off 3rd lock-up. He plans to do more drag racing with it vs pulling, otherwise I would swap out his gears for some 4.56s at the very least...
 
The 205 is basically a 2 to 1 in low lock. 1.96 I think to be exact.
I tried locking the convertor a couple of times with 3.54 gears in a one ton with towing twins. It wouldn't do it in drive low lock and the lower low lock in the later tranfer case. I'm guessing it was in the high 4 to low 500 horse range.
 
Some questions about this. All the replacement parts needed such as tranny, starter, bellhousing, and flexplate can come from 94-02? The thing your calling adaptor, is that actually an adaptor or a 94-02 bellhousing?
 
aer212 said:
Some questions about this. All the replacement parts needed such as tranny, starter, bellhousing, and flexplate can come from 94-02? The thing your calling adaptor, is that actually an adaptor or a 94-02 bellhousing?
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its called an adaptor because it bolts to the block and bolts to the transmission bellhousing.

Left is for 47rh, Right was the A518.

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reason I'm asking is I have a 2000 24 valve sitting with a bellhousing adapter and starter. So all I need now is tranny, and flexplate?
 
J. Keith, how does the 2000 24v tcm hook up to the 47rh to control lockup and overdrive? My understanding is that would work with a 47re but not the 47rh.
 
You can find them forsale on ebay at times.. THink I gave $75 for the adapter. Flex disc is fine to re-use unless it's original or your headed for 500 hp.
 
I was wondering if anybody had any info as to if the 518 and the 47rh have the same length of output shaft. What I have understood from other people I have talked to is that the 518 has a longer output shaft, thus meaning when you do the swap you will run into issues because the t case to transmission output splines will only be engaged about 1/2" and what I have heard is you will need to try and get a special adaptor made to do this swap correctly? Any body have both transmissions laying around they want to measure for me? Thanks for any info.
 
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67fordcummins said:
I was wondering if anybody had any info as to if the 518 and the 47rh have the same length of output shaft. What I have understood from other people I have talked to is that the 518 has a longer output shaft, thus meaning when you do the swap you will run into issues because the t case to transmission output splines will only be engaged about 1/2" and what I have heard is you will need to try and get a special adaptor made to do this swap correctly? Any body have both transmissions laying around they want to measure for me? Thanks for any info.
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If you plan on shooting for some decent HP it may be worth while to just convert your A518 to lock-up...All you need is a lock-up front pump (or just the stator support/reaction shaft), input, VB or in some cases just components, TC, and of course the adapter/starter.

Most of the VBs are set up for lock-up but are missing a valve, a couple of springs, and the second solenoid on the bracket. But really with the cost of a complete VB might as well get one for a 47RH from Georend. Front pumps are inexpensive and aren't a bad idea to replace on a rebuild anyway. The input a guy might just as well go billet right off the bat since I'd imagine most that are doing the swap aren't exactly stock in the fuel and air department. And of course might as well get a decent converter too. I mean it's basically the same parts list for building a 47RH anyway. The one difference that I see in them is that the low reverse band and the servo that applies it is the same as the gas transmissions. It's a single wrap band that is applied by the 2.81" servo vs the double wrap band applied by a 2.49" servo in the 47RH trans...They still use the 14 element low roller clutch and the intermediate shaft is the same for sure.

I didn't measure the output shaft but they appear to be the same. The difference seems to lie with the actual housing itself. The RH is set up for a seal to be pressed in that rides on the input of the T-case, and has a weep hole at the bottom. The A518 diesel housing does not use a seal and has no weep hole. I wonder if it's also cast shorter on the 4x4 adapter end so the 205 engages more splines.

I just went through an A518 for a guy and should have taken pics to show what all I was talking about with the VB and with the low/reverse band. I could have sat it next to a 47RH case even for direct comparison.
 
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The 518 and 47rh output shafts are the same length and will have the same amount of engagement. On the 47rh you will have to remove the output seal and you will have to seal the t-case to trans mating surfaces with RTV including the weep hole. There will be trans fluid in this area between the two, just like any 1st gen. You will use the stock spline coupler to mate the 205 to the 47, just like a 1st gen setup.

If your buddy is looking for 500hp and sled pulling and drag racing then sooner or later he will be needing to upgrade to the 29 spline 205 found in manual trucks and use an adapter coupler to mate it to the trans.
 
rockjeep73 said:
The 518 and 47rh output shafts are the same length and will have the same amount of engagement. On the 47rh you will have to remove the output seal and you will have to seal the t-case to trans mating surfaces with RTV including the weep hole. There will be trans fluid in this area between the two, just like any 1st gen. You will use the stock spline coupler to mate the 205 to the 47, just like a 1st gen setup.

If your buddy is looking for 500hp and sled pulling and drag racing then sooner or later he will be needing to upgrade to the 29 spline 205 found in manual trucks and use an adapter coupler to mate it to the trans.
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I had heard the inputs on the 205s behind autos were weak... I just didn't know where there limit was. Looks like my two guys with p-pumped 1st gens will be looking for new transfercases soon.
 
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