Transmission Tuner

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Transmission Swap Comparisons

If you are considering a transmission swap the following comparison information can be very helpful in your decision making.   See cost comparisons farther down the page.  If you want to skip general information and read comparisons between some of the best diesel pickup transmissions follow the links below:

Allison vs 68RFE

Allison vs 5R110

5R110 vs 4R100

68RFE vs 48RE

Gear Ratio Comparisons and General Information:

Dependability and the cost for the swap are what most consider first.  Don't overlook gear ratios, as how the transmission will work with the rest of your drivetrain is very important when considering the efficiency and power transfer gains a transmission swap can offer.  Remember, the higher the number the lower the gear- which translates to slow speed but the ability to pull or accelerate.  The lower the number the higher the gear- which translates to higher speed/lower rpm. 

The table below lists out the gear ratios of many popular transmissions used in diesel pickups, and if you click on the transmission name in the table it will take you to general information about that transmission.  Use your browser's back arrow to get back to the table below:

Transmission 1st 2nd 3rd 4th 5th 6th Reverse
Allison® 5 speed 3.10 1.81 1.41 Direct .71 N/A 4.49
Allison® 6 speed 3.10 1.81 1.41 Direct .71 .61 4.49
Dodge® 47/48RE 2.45 1.45 Direct .69 N/A N/A 2.20
Dodge® 68RFE 3.23 1.83 1.41 Direct .81 .62 4.44
Aisin® AS68/69RC 3.74 2.00 1.34 Direct .77 .63 3.54
Ford® 4R100 2.71 1.54 Direct .71 N/A N/A 2.88
Ford® 5R110 3.09 2.20 1.54 1.1* Direct .71 2.88
Ford® 6R140 3.97 2.32 1.52 1.15 .86 .67 3.13
Dodge® Diesel NV4500 5.61 3.04 1.67 Direct .73   98 up 5.61 93-97 5.04
Dodge® Diesel NV5600 5.63 3.38 2.04 1.39 Direct .73 5.63
Dodge® Diesel 05-07 G56 6.29 3.48 2.10 1.38 Direct .79 6.29
Dodge® Diesel 07.5-  G56 5.94 3.28 1.98 1.31 Direct .74 5.42
Ford® ZF-6 5.79 3.30 2.10 1.31 Direct .72 5.23

As you can see, transmission gear ratios vary widely, even among manual transmissions.  The ratio change between gears is an important factor, especially when using an engine with a narrower rpm/power ratio such as the 5.9 Cummins®.  4 speed transmissions cause large rpm drops due to wide spacing of ratio changes, and require the engine to rev up to a higher shift rpm so the rpm drop after the shift is not too low.  No matter what engine you have, these wide ratio changes result in poorer fuel economy, and require the engine to work harder when pulling heavy loads.  This is why a 6-speed automatic transmission with double overdrive ratios is helpful, especially if you spend a good amount of time at speeds above 65 MPH but still need a strong first and reverse gear for the jobsite.

If you have Microsoft Excel or Open Office, I can email you a spreadsheet that has really handy calculators to help you see how different gear ratio combinations will work for you. 

If you are only interested in information about manual transmission swaps, click here to go to that section of this webpage.

Allison® 1000

Allison® 5 speed Ratios 1st - 3.10 2nd - 1.81 3rd - 1.41 4th - Direct 5th - .71 N/A Reverse - 4.49
Allison® 6 speed Ratios 1st - 3.10 2nd - 1.81 3rd - 1.41 4th - Direct 5th - .71 6th - .61 Reverse - 4.49

The Allison® 1000 5 and 6 speed transmissions have been regarded as excellent transmissions since they first made their appearance in the Chevy pickups in 2001.  It has the lowest reverse yet of automatics, so if you are backing heavy trailers up hills you may find that part of this trans very beneficial.  The gear split between 4th and 5th isn't as good as a 68RFE, but is the same as the Ford® transmissions. The two overdrive ratios of the six speed are great if your gear ratio and tire size are able to utilize them, and the Allison 6 speed has the highest overdrive of all listed in the chart.  If you have 37 tires and a 3.55 gear ratio, sixth might not be much good to you, except for low throttle cruising at freeway speeds.

Most performance experts agree that the Allison® 1000 transmission will not handle power levels over 350 hp without upgrades, and a torque converter that is designed to work with a Cummins engine is recommended.  Tuning can help a stock transmission live behind modest performance increases, but clutch upgrades are recommended for anything serious- such as 400 hp. The drawbacks to swapping this transmission into a Ford or Dodge pickup is the expense. Custom adapter and flex plates, driveshaft modifications, control system and tuning, and getting the transfer case you want connected if your truck is a 4x4 all adds up to a very significant investment. 

I do not recommend aftermarket control systems for this transmission at this time.  There are some out there but they still require a OEM control module and that makes this swap that more complex - and you will likely need more equipment than you realize to make it work properly.  I offer a stand alone 6 speed control system that is tunable and uses OEM Allison components.  Read more about it here.

Dodge® 47RE/48RE

47/48RE Ratios 1st - 2.45 2nd - 1.45 3rd - Direct 4th - .69 Reverse - 2.20

Even though there is a ton of aftermarket parts available to make these transmissions much stronger than they are in OEM form, I would say that they are a really poor transmission for the daily work truck.  I don't recommend them as an option for a transmission swap, unless your engine will break whatever is behind it anyway and you plan to rebuild or replace your trans after a few race events.  Getting one built to handle even a 350 hp Cummins will cost you a good chunk of money and it will still give you problems. Band adjustments are necessary to keep them from burning up, line pressure control is poor, and the filter to valve body connection was designed in the 1960's, depending on two or three tiny screws to hold it on.    

As more options become available many truck owners will be swapping the 47/48RE out for something much better.  The high reverse and the wide 3-4 gap make it a really poor performer in a work truck.  Perhaps the worst issue with the 47RE is the control system, as solenoid and governor control failures are very common.  The 48RE control system is a little better, and it got stronger 6 pinion planetaries, but many 48RE owners are still having troubles with their trans behind the stock Cummins®.  If you have a stock Cummins or just one that is a little hopped up, I recommend replacing the 47 or 48RE with a 68RFE.  If you are racing I recommend a Ford 4R100.

Dodge® 68RFE

68RFE Ratios 1st - 3.23 2nd - 1.83 3rd - 1.41 4th - Direct 5th - .81 6th - .62 Reverse - 4.44

I have a 68RFE in my 97 Dodge behind the stock 12 valve Cummins.  I have it working quite well with the PCS TCM-2000, and am wrapping up re-development with the new PCS TCM-2800.  It may be possible to use a 2010 and up ECM/TCM to run one in a swap but it would take quite a bit of wiring and sensors. EFI Live is pretty burdensome to use to adjust the shift points.  Rather than mess with all of that I have decided aftermarket is a better way to do it.  I sell parts with full tech support to swap these transmissions into Dodges and Fordcummins conversion trucks, so if you are interested read more about it here

The 68RFE was a huge improvement in the Dodge transmission market, and even in the transmission market in general. It has 6 pinion planetaries and hydraulic accumulation for all shift events.  The gear ratios are in my opinion the best available for the Cummins diesel so far.  The 4th to 5th shift is much closer than most transmissions, so the engine does not have to rev as high to survive a big rpm drop that wider overdrive ratios cause. It also has the second lowest reverse, and double overdrive- which is really nice for freeway cruising. Be careful, if you have 37" tires and a 3.55 axle ratio, 6th may not benefit you unless you are road racing, although the low first gear and reverse will still be very beneficial.  Gear ratio calculators can be used to see the difference a 68 will make for you.

There are a few adaptability issues to using these transmissions behind a 05 and older Cummins that I have solved, and the swap is much cheaper than an Allison® conversion when replacing a 47 or 48RE, since you often don't need to do driveshaft modifications and you don't need an aftermarket flexplate.  Unfortunately there is no PTO provision and monster power is a tough challenge to handle.  If you need a PTO on the trans (engine driven hydraulic pumps are available), and you want more than 400hp, I recommend the Allison. There are some durability issues with the 68RFE when power increases over 350 hp put it to the test, especially with the stock tuning, but aftermarket tuning and parts are available to address that.  Power increases are a test for the Allison trans as well, so unfortunately if your Cummins is turned up you will need to spend some money on aftermarket transmission parts no matter what. 

Aisin® AS68RC/AS69RC

AS68RC Ratios 1st - 3.74 2nd - 2.00 3rd - 1.34 4th - Direct 5th - .77 6th - .63 Reverse - 3.54

These transmissions have generated a fair amount of interest and are generally regarded as a tough trans- but it may still be a good while before they become a viable option for a swap.  It may be possible to use one with the PCS controller, and I have had several guys inquire about it so I will most likely be testing one out soon.

They are not as easy to find as the others listed here, and I'm not overly impressed with the gear ratios.  First gear is probably a bit too low in most applications- not so bad for a heavy work truck perhaps, but work trucks typically have lower axle ratios anyway.  One would expect to see a lower reverse ratio with the low 1st gear as well, but it is not as low as it should be.  1st and reverse ratios should be similar to work well with the ideal axle ratio, with reverse having the lower ratio if they differ at all.  In other words, low first is nice, but if you don't have an equally low reverse you may need a lower axle ratio to prevent issues backing heavy trailers.   If the two ratios are similar, a higher axle ratio can be used to idealize the drivetrain efficiency. The ratio spacing between 4th and 5th is a little wider than the 68RFE, but closer than the Allison and 5R110.

Ford® 4R100

Ford 4R100 Ratios 1st - 2.71 2nd - 1.54 3rd - Direct 4th - .71 Reverse - 2.88

The Ford® 4R100 is still a favorite with many swappers and racers- I think mainly because it is familiar and proven for being something that can be built to handle a lot of power and is relatively easy to control and tune with aftermarket transmission controllers.  Racers will probably never leave it, for the previous good reasons, and it is easy to find another core if you break one.  If your work truck has a 4.10- 4.88 axle ratio and never sees the interstate, the 4R100 works fine.  Generally speaking, only a double overdrive transmission will be much better as far as ratios go.   

The 4R100 comes in the gas or 7.3 diesel bolt pattern.  The gas version is almost the same as the 5R110 pattern (the gas 4R100 is missing two holes on the top) , so it is possible to bolt a gas 4R100 case to most aftermarket 5R110 adapters and even 6.0s and 6.4s.   Gas versions may have cheaper planetaries and other hard parts in them so don't use one behind a high performance diesel without first sending it to a reputable transmission builder.

The E4OD is quite similar although it lacks speed sensors and bell housing bolt patterns are limited to the small block, M/460, or Diesel patterns.

Ford® 5R110

Ford 5R110 Ratios 1st - 3.09 2nd - 2.20 3rd - 1.54 4th - 1.1* 5th - Direct 6th - .71 Reverse - 2.88

The Ford 5R110 isn't a bad trans to have if you already have one- but with better swap options available now I wouldn't recommend swapping one in a Dodge Cummins or to replace a 4R100 in a Cummins conversion.  There is a little interest out there in replacing the E4OD or 4R100 behind a 7.3 with one- but it will take adapter kits to make it possible.  You'll never break an output shaft and the extra gear is probably worth it if you are doing really heavy towing and you don't want to use a 68RFE or an Allison.  Unfortunately the spacing between 1st, 2nd, and 3rd gears is a bit too close for it to be ideal, so it's not much different than the 4R100 as far as gearing goes.  The lower first gear is nice, but unfortunately reverse isn't any lower than the 4R100.  Fourth gear is a joke that Ford played on everyone- it never really gets used unless the control system isn't happy about something, and isn't worth using anyway- 5th is the same as the 4R100 3rd gear and 6th is the same as the 4R100's 4th. 

The best control system is the custom tuned OEM Ford® TCM for this trans in 03-07 trucks, although the PCS TCM-2000 controller does work with proper tuning for racers or guys that already have it and don't want to spend a lot of money converting back to the stock system.   The PCS 2800 controller still needs more time to be learned and proven with these transmissions.

Ford® 6R140

Ford® 6R140 Ratios 1st - 3.97 2nd - 2.32 3rd - 1.52 4th - 1.15 5th - .86 6th - .67 Reverse - 3.13

The 6R140 is one that swappers are still dreaming about, and as far as I know there hasn't been anyone that has pulled it off yet.  I'm not too interested in any control development at this time, even though it could be the strongest automatic out there in stock form - once again the gear ratios are not ideal.  It has the lowest first gear ratio for an automatic, but the very unfortunate fact is that the low first gear is not complemented with an equally low reverse gear.  If it had a lower reverse, tall tires or higher axle ratios could be utilized to make it a good combination.  Even if that was better, the spacing is wider than other transmissions, so accelerating would still be more choppy and less efficient than it could be.  Maybe the next trans Ford builds will be better.

The Best Diesel Transmission Swaps Compared

Allison vs 68RFE

Allison 6® speed Ratios 1st - 3.10 2nd - 1.81 3rd - 1.41 4th - Direct 5th - .71 6th - .61 Reverse - 4.49
68RFE Ratios 1st - 3.23 2nd - 1.83 3rd - 1.41 4th - Direct 5th - .81 6th - .62 Reverse - 4.44

Reasons to choose an Allison instead of a 68RFE:

Reasons to choose a 68RFE instead of an Allison:

Allison vs 5R110

Allison 6® speed Ratios 1st - 3.10 2nd - 1.81 3rd - 1.41 4th - Direct 5th - .71 6th - .61 Reverse - 4.49
Ford 5R110 Ratios 1st - 3.09 2nd - 2.20 3rd - 1.54 4th - 1.1* 5th - Direct 6th - .71 Reverse - 2.88

Reasons to choose a 6-speed Allison instead of a 5R110

Reasons to choose a 5R110 instead of a 6 speed Allison

5R110 vs 4R100

Ford 5R110 Ratios 1st - 3.09 2nd - 2.20 3rd - 1.54 4th - 1.1* 5th - Direct 6th - .71 Reverse - 2.88
Ford 4R100 Ratios 1st - 2.71 2nd - 1.54 3rd - Direct 4th - .71 Reverse - 2.88

Reasons to choose a 5R110 instead of a 4R100 with a Cummins engine.

Reasons to choose a 4R100 instead of a 5R110

68RFE vs 48RE

68RFE Ratios 1st - 3.23 2nd - 1.83 3rd - 1.41 4th - Direct 5th - .81 6th - .62 Reverse - 4.44
47/48RE Ratios 1st - 2.45 2nd - 1.45 3rd - Direct 4th - .69 Reverse - 2.20

Reasons to choose a 68RFE instead of a 48RE

Reasons to choose a 48RE instead of a 68RFE (Replace a 68 with a 48 in a 07.5+ Dodge for example)

Trans Swap Cost Comparisons

Choose Wisely!  No transmission swap worth doing is cheap.  The tables below show cost estimates for what you would pay for parts and labor for a transmission swap and are based on the following definitions:

Trans Swap in 89-04 Dodge Used Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Dodge® 48RE/PCS in 89-02 2300   2800     600 5700.00
Allison® 2500 1554 2000 1500 1000 1725 10,279.00
Dodge® 68RFE 3000 700 1200 225   750 5875.00
Aisin® AS68/69RC *if possible 3000 700 1200 225 750 ? 750 6625.00
Ford® 4R100 1800 1554 1000 600 1000 1500 7454.00
Ford® 5R110 2300 1554 1150 600 1000 1500 8104.00
Dodge Diesel NV4500 2375     225 400 1500 4500.00
Dodge® Diesel NV5600 3725     225 400 1500 5850.00
Dodge® Diesel G56 3875     225 400 1500 6000.00
Ford® ZF-6 3175 929 600 1000 1500 7204.00
Trans Swap in 05-06 Dodge Used Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Allison® 2500 1554 2000 1500 1000 1725 10,279.00
Dodge® 68RFE 3000 225 1200 225   750 5400.00
Aisin® AS68/69RC *if possible 3000 700 1200 225 750 ? 750 6150.00
Ford® 4R100 1800 1554 1000 600 1000 1500 7454.00
Ford® 5R110 2300 1554 1150 600 1000 1500 8104.00
Dodge® Diesel NV5600 3725     225 400 1500 5850.00
Dodge® Diesel G56 3875     225 400 1500 6000.00
Ford® ZF-6 3250 929 600 1000 1500 7279.00

Built Trans Swap in Dodge Cost Comparisons:

These comparisons are the same as above but instead of using a used transmission the cost for a high performance transmission is used.  All the transmissions listed are high level builds, and core charges are added to the price. Keep in mind that the Allison is the strongest potential build, and the 48RE/PCS is still the weakest/worst option in my opinion.  I include it here to show how much you are going to spend for it with a custom valve body and controller. If you are still tempted to use a 48RE with the PCS controller, give me a call and I give you more details on the cost of the swap.   

Sometimes it is cheaper to buy a core to send in than pay the core charge- but since the cost of cores vary I only lowered a $2200 core charge by $400.00, and I left a $1600 core charge alone.

If you don't see a transmission listed it is because there are no aftermarket high performance parts available for it yet.

Trans Swap in 89-04 Dodge Built Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Dodge® 48RE/PCS in 89-02 7100   2800     600 10,500.00
Allison® 8068 1554 2000 1500 1000 1725 15,847.00
Dodge® 68RFE 10,060 700 1200 225   750 12,935.00
Ford® 4R100 6026 1554 1000 600 1000 1500 11,680.00
Ford® 5R110 6326 1554 1150 600 1000 1500 12,130.00
Trans Swap in 05-13 Dodge Built Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Dodge® 48RE/PCS in 07-13 7100*   2800     600 10,500.00
Allison® 8068 1554 2000 1500 1000 1725 15,847.00
Dodge® 68RFE 10,060 250 1200 225   750 12,485.00
Ford® 4R100 6026 1554 1000 600 1000 1500 11,680.00
Ford® 5R110 6326 1554 1150 600 1000 1500 12,130.00

* May be an extra charge for built in converter spacer- if no spacer is built in or used, an older adapter is needed.

Trans Swap Cost in Fordcummins Comparison:

Just a few definition clarifications on these.  When swapping a Dodge transmission into a Fordcummins truck, the builder should seriously consider using a hybrid transfer case with a fixed rear yoke.  I figure if a guy is going to go to the trouble to make the best truck out there, he should probably have the best type of transfer case too.  The transfer case cost is based on an estimate of what it would cost to send in your Ford t-case to a custom shop and have a reman hybrid t-case built for you.  Assume you already have done the Cummins engine conversion- the adapter plate cost is only included in case you have to change yours.  Gas version 4R100 transmissions have the same basic bolt pattern (with two bolts missing at the top) as the 5R110- but diesel version 4R100s are totally different.  Be aware that I did not add any cost for a performance built 4R100 or 48RE- the costs listed are for stock used transmissions.  I would not recommend using either of those transmissions in stock form behind even a mildly turned up Cummins diesel.

  When swapping a newer or older Ford trans be aware that the 5R110 and the 6-speed manual transmissions have a larger output shaft than the 4R100, so your input may need to be changed.  The 7.3 6 speeds can even have a different one yet- but all 6.0 6 speed versions are the same as the 5R110. 

Trans Swap in 99-10 Ford with 89-04 Cummins Used Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Dodge® 48RE/ 03-04 C-Rail 2300     1300 750 1300 5650.00
Dodge® 48RE/PCS 89-02 2300   2050 1300 750 1300 7700.00
Allison® 2500 1554 2000 1500 750 1725 10,029.00
Dodge® 68RFE 3000 700 1200 1300 750 1300 8250.00
Aisin® AS68/69RC *if possible 3000 700 1200 1300 750 1300 8250.00
Ford® 4R100 1800 1554 1000 250   600 5204.00
Ford® 5R110 2300 1554 1150 250   600 5854.00
Dodge® Diesel NV4500 2375     1300 750 1500 5925.00
Dodge® Diesel NV5600 3725     1300 750 1500 7275.00
Dodge® Diesel G56 3875     1300 750 1500 7425.00
Ford® ZF-6 3250 800   250 600 1000 5900.00
Trans Swap in 99-10 Ford with 05-06 Cummins Used Trans Adapters Controller Transfer Case Drive Shaft Installation Total
Dodge® 48RE/ 03-04 C-Rail 2300     1300 750 1300 5650.00
Dodge® 48RE/PCS 89-02 2300   2050 1300 750 1300 7700.00
Allison® 2500 1554 2000 1500 750 1725 10,029.00
Dodge® 68RFE 3000 250 1200 1300 750 1300 7800.00
Aisin® AS68/69RC *if possible 3000 700 1200 1300 750 1300 7800.00
Ford® 4R100 1800 1554 1000 250   600 5204.00
Ford® 5R110 2300 1554 1150 250   600 5854.00
Dodge® Diesel NV5600 3725     1300 750 1500 7275.00
Dodge® Diesel G56 3875     1300 750 1500 7425.00
Ford® ZF-6 3250 800   250 600 1000 5900.00

Manual Trans Swaps

Custom truck owners often consider a manual trans swap because they are extremely frustrated with issues they have had with their automatic.  Aftermarket controls and tuning for automatics can be your worst nightmare if you hate computers and don't get good support, but don't give up on your automatic too easy if you have already invested in it. 

Most manual trans swaps are fairly straightforward, be very careful to do your homework.  Hydraulic clutch arrangements, especially when swapping manufacturers, can be a little tricky. You may need to re-drill holes in your frame for your transmission crossmember, and some trucks require transmission tunnel modifications, since automatic trucks often have a lower tunnel. 

When considering swapping a manual trans in your truck to replace an automatic, or even putting a lift kit and tall tires on your manual trans truck, beware of gear ratio drawbacks.  If you have tall tires and high gearing you will be stuck starting out in first gear at every stop light, or slipping the clutch excessively in second- and that is a nightmare that is just as bad as living with poor automatic trans tuning. The tall tire issue is especially tough if you have a ceramic clutch- it will chatter your teeth out starting in second and hop like a rabbit in first.  Remember, the need for close ratio spacing in diesel trucks is the reason why most semi- trucks have 9-18 gears!

If your truck is geared right and you don't mind shifting gears, manual transmissions are fine, however they do typically have wider ratio spacing that can be very annoying and not so efficient when pulling a heavy load in hilly country.  There are two options that can help this problem:

Gear ratio data was gathered from reliable public data available on the internet.