Transmission options

DPC

DPC

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Jan 2, 2012
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I have a few questions for transmissions options in a possible super street truck

1. With advances in tech on the Allison will it hold 9.XX passes for a race season, or will tear downs be needed every few races?

2. If the Allison can be made reliable on 9.XX passes what kind of costs are we looking at?

3. Can the Allison compete with a duraflite on cost and reliability?

My engine build and install is almost complete, I am looking for the best course of action on a transmission to be competitive in the super street class. I would like to start T&T summer of 2015. I need to have the cage built this winter and a plan for a transmission. Thanks for your time.
 
H

Hot COCOAL

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Jun 9, 2012
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Has anyone ran into the 9's with an Allison?
If so how many times?

I know guys run low 10's with the Alli quite regularly, but for some reason I thought the 9's were out of the Alli's functional operating range???

Isn't there 48re conversion option as well? I thought that the 48re (dodge) trans was a cheaper route than a duraflite and held up a bit better than the Allison for high HP applications?
 
LBZ

LBZ

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If you want to run 9's consistently then I believe the Duraflight is the way to go
An ally will do it but I don't believe for near as many passes as a Duraflight.
 
paint94979

paint94979

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Duraflite is a 48/47re setup... At that weight and power level I doubt anything is going to last a whole season. Several guys have gone 9's with an Allison but in a 6000+lb truck it will need to be refreshed most likely.
 
S

S Phinney

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Aug 15, 2008
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Brett went back to the th400. The Ford Trans could not keep converters in it. He is at 4500 lbs as well. The allison can get you there but the duraflite would be better for a pure competition truck.
 
IdahoRob

IdahoRob

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IMHO the 47/47re is the way to go for your needs. There have been a couple trucks that have gone 9's with an Allison but never consistent rounds in the 9's. The ET is always slower for the MPH as you may have noticed with a high HP truck with an Allison.

The 48re has been lasting a full season for us except an issue for this year. Most problems we have had over the years with the 48 conversion is torque converters but have made huge gains in that department also. We had a converter last all year except when we had a valve body screw up and launched in 3rd, smoked the converter.

Here is a pass that shows how crisp and quick the shifts are. If anyone wants some more info, feel free to email me [email protected] and i'll try and explain better.

https://www.youtube.com/watch?v=mKWy7GAkSJ4
 
Evan@InglewoodTrans

Evan@InglewoodTrans

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There are quite a few people trying very hard to make the Allison do what everyone says it can't. I don't think it will be very long before it can hold its own just fine in a 6000 pound or less truck. Until then a 47/Duraflite seems to be the best option we have.
 
03badmaxxx

03badmaxxx

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Some data for you to look at in comparison for both. The Alli has made leaps and bounds and i believe it will at some point be more of a consistent trans but i don't think it will be able to produce times like the TorqueFlite. At least, not anytime soon.

Allison gear ratios:
1st- 3.10 2nd-1.81 3rd-1.41 4th-1.0 5th-0.71

TF gear ratios:
1st-2.45 2nd-1.45 3rd-1.0 4th-0.69

Main difference between both transmissions:
TF travels further in first, has less RPM drop between gear changes, 70lbs + lighter, less parasitic drag

The reason the TorqueFite shifts faster is mainly because its not a clutch on clutch shifted transmission. It relies on the balance of fluid in the front servo to release the band.

First gear the TF is on the sprag, so the shift from 1st to 2nd all it has to do is put the band on, where as the allison has to release the c5 clutch and put on the c4 de-fueling in the gear change. (some try to tune around this) but anyway you look at it de-fueling=loss momentary of power.

With a TF your engine could be at 3500 RPM in 1st gear and the drive shaft is at 1428 (ish) with the Allison the engine at 3500 and the drive shaft at 1129RPM (ish). So with the Allison while the transmission is in reduction (1-4th) gear you have to turn the motor faster to accomplish the same drive shaft speed. This calculates to a 7MPH difference in 1st gear, 12mph difference in 2nd, 3rd gear TF goes to Direct drive (1:1) and thats a 24 MPH difference compared to the allison 3rd. The allison has to go from 1.81 to 1.41 which means it has to make another gear change where the TF is still pulling. This means the Allison has to shift 2 times before it catches up to the TF. The 4r100 is a great comparison however the shaft size is a major downfall when it comes to heavier trucks. TF has 3 different shaft sizes that can be used. The other nice thing about the TF is that is has multiple Valve body options, you could run full manual, full manual with the pcs controller controlling O/D and Lockup, reverse manual, full electronic and a few other custom options.
 
Last edited:
DPC

DPC

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Jan 2, 2012
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Adams, TN
IdahoRob said:
IMHO the 47/47re is the way to go for your needs. There have been a couple trucks that have gone 9's with an Allison but never consistent rounds in the 9's. The ET is always slower for the MPH as you may have noticed with a high HP truck with an Allison.

The 48re has been lasting a full season for us except an issue for this year. Most problems we have had over the years with the 48 conversion is torque converters but have made huge gains in that department also. We had a converter last all year except when we had a valve body screw up and launched in 3rd, smoked the converter.

Here is a pass that shows how crisp and quick the shifts are. If anyone wants some more info, feel free to email me [email protected] and i'll try and explain better.

https://www.youtube.com/watch?v=mKWy7GAkSJ4
Click to expand...

Wow, very impressive shifting! I will send you an email to pick your brain about a few things on your setup. Thanks to everyone for all the information.
 
Mike L.

Mike L.

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If some machinist could fix the 4th gear problem with the 4L80E; it would blow away the duraflite. The 2/3 shift on the duraflite loses ET by 3/5 tenths. It's still faster than an Allison as far as shifts go. Gear ratio in the duraflite is much better and it doesn't require defuel. The 4L80 would blow it away, if 4th was fixed.
 
paint94979

paint94979

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Btw you can save a lot of money by supplying your own built 47re and using a manual valvebody instead of the PCS
 
TheBac

TheBac

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Mike L. said:
If some machinist could fix the 4th gear problem with the 4L80E; it would blow away the duraflite. The 2/3 shift on the duraflite loses ET by 3/5 tenths. It's still faster than an Allison as far as shifts go. Gear ratio in the duraflite is much better and it doesn't require defuel. The 4L80 would blow it away, if 4th was fixed.
Click to expand...

Whats wrong with 4th gear?
 
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