2wd Allison swap into 93 C2500(HD): how much modifying?

[GM Guy]

Hey guys,

A guy with a junk addiction can only go so long without wanting to buy something, so Guess what I found!

1993 C2500(HD) ECLB Gloss white body/gray interior pickup with presumably plenty of miles, as it has a completely shot 4L80E. few if any dents, and little seat wear, so a highway rig.

Now knowing that I have to have a 1995 and earlier 4L80E (91-95 had different wiring and controls, correct?) due to wiring, and the realization by some (Warwagon) that the 4L80E isnt a bulletproof towing tranny got me wondering, what does an Allison swap entail?

surely as far as electronics go, older is better, right? so for a cheap, easy swap I am limited to a 5 spd from 01-05?
how is the computer setup? are they standalone computers integrated to the GM truck, or is it all integrated? If it is integrated, who sells the best bang for the buck standalone controller?

would any working 5spd takeout (for example, a 200K+ miled one out of a rollover for instance) hold up great with no modification whatsoever, and just fluid and filter change behind a 93 6.5L? (provided it was cared for to start with)

most importantly, will it fit in the tunnel? keep in mind, everything will be 2wd. minimal hacking preferred.

what would cooling entail? does it need a better cooler than stock 4L80E? (as in are the fittings big enough)

finally, what would the linkage be?

the truck right now is 700 bucks, so the goal is to make it as low buck as possible, but still try and do it right.

This is just a maybe deal, so dont spend too much time writing me an install guide!

any input appreciated,

thanks folks!

 

[GM Guy]

example candidate: http://www.ebay.com/itm/2003-Alliso...Parts_Accessories&hash=item41681c45f5&vxp=mtr

if the swap is possible, this is in driving distance, so it very well could be the one I will be using.

 

[THEFERMANATOR]

You can use any 4L80E/4L85E in a 93, but you will have to modify the valve body to work with the 91-93 lock-up solonoid or get an updated PROM for the ECM as the 91-93 used a slightly different lock-up solonoid than the 94+ did(455HZ for 91-93 VS the 855HZ for 94+, not certain on the frequency, but know this is close). The ALLISON swap WILL cost you ALOT more than a rebuild on the 4L80E, and in the end you will lose about 10% of the available RWHP as the ALLISON has ALOT more parasitic drag to it VS the 4L80E trans has. If your dead set on an ALLISON 1000, then plan on spending $1200-1500 for a good useable ALLISON, another $150 for a TCM, probably another $200-225 for the wiring harness and such(not counting modifying it to be stand alone), a TPS that will work with the ALLISON TCM, possibly another $150 for ALLISON to flash the TCM, and if you want tow/haul mode you will either have to go with a PCS XFC box with the destroked software or a GM BCM wired in(this is if you go with GM DURAMAX software in the TCM, you could probably get a custom tune in it from ALLISON but the rules surrounding the GM agreement prohibits them from doing tunes for anything smaller than a ton and a half truck). So if you can do all of the wiring and driveline changes as well as modifying your crossmember, you will probably be into it for around $3K to swap in an ALLISON, and this is probably a low number. A 4L80E rebuild with a shift kit, ALTO clutches, and TRANSTAR torque converter will handle whatever the 6.5 can throw at it and cost you less than $2K.

 

[red]

theres no real way to do it for cheap, unless you got lucky and found a donor truck that had been wrecked but the trans was fine.

If you want to save money but still plan to tow your cheapest options would be either a th400 auto or sm465 manual. both are extremely solid and reliable, just lose overdrive

 

[WarWagon]

Change the fluid every 25K and see how long the current trans lives.

A better rebuild on the 4L80E specifically a good converter clutch will go a long way. 50K out of a stock rebuild isn't bad esp since it only cost me $1200 installed with new OD planetary gear set. I could have paid more esp for a better converter with better clutch. Over run clutches are the weak link only with the TCC locked for grade braking to the extreme. The TCC clutch is next in the weak link chain. Avoiding the TCC override switch would have had more life.

THEFERMANATOR has a good plan for them sounds like.

Otherwise the 4L80E goes behind the Duramax in vans.

 

[GM Guy]

so you folks wouldnt recommend the ally from the e-bay link? that guy loves parting trucks out, so what would one need from the truck?

 

[red]

Fermanator's post lists what you would need to make the trans work behind the 6.5. It's doable, just not cheap.

 

[L98TPI]

Here's a thought from left field. Since you're starting with a 6.5/4l80e, one of TCI's 6 speed 4l80e's might be a better way to go if you are going to spend a lot of money and time. Cuz time is money.
Rated to 1000hp and a lifetime warranty, bell housings for many applications (6BT? ). They must have re-engineered the OD so it can take the same hp as direct.
http://www.youtube.com/watch?v=oW0LyOvVjl4
Really cool but 6-7 grand.

 

[THEFERMANATOR]

Here's a thought from left field. Since you're starting with a 6.5/4l80e, one of TCI's 6 speed 4l80e's might be a better way to go if you are going to spend a lot of money and time. Cuz time is money.
Rated to 1000hp and a lifetime warranty, bell housings for many applications (6BT? ). They must have re-engineered the OD so it can take the same hp as direct.
http://www.youtube.com/watch?v=oW0LyOvVjl4
Really cool but 6-7 grand.

The 4L80E can take 100)HP with just a kit and good convereter, what they don't mention is how much torque it can handle. All kidding aside, a properly built 4L80E can handle 99% of teh 6.5's out there, and theers really no need to go to an ALLISON to LOSE RWHP.

 

[L98TPI]

Errr :???:
The point of my post was that TCI has found a way to make the over drive take 1000hp and the torque associated with that. So then they can split 1st, 2nd, and 3rd gear with the OD via a special valve body and their PCM. Plus they have removed the cast on bell housing in favor of a (SPI rated BTW) removable bell that lets them with special torque converters put a 4L80E on all popular applications.

Six speeds will really keep diesels in their power band. Also no need for making an axle ratio choice, tow or not, flatland or mountains. You pick for flat land economy in 6th, 5th is your tow OD, 4th is your hill climber. :hihi:
My buddy has a 5 speed auto in a gas truck. Its makes a hell of an difference for towing.

I'm wondering if Cummings 4/6BT is in that popular list :thumbsup:

 

[GM Guy]

went to Destroked.com saw some prices. Wind has oficially left the sails!

so where is the wiring and slenoids mounted on a 4L80E? can I swap valve bodies off the bad one onto a newer one and be plug and play? (there was a goodwrench 4L80E with 10K miles on it on ebay for 475 bucks out of a 2000 cargo van) murphys law, the parts truck I am getting stuff off of (a auto equipped version of my 93) had the auto sold before I met up with the guy. just needed converted from a 4wd to a 2wd. the guy who bought it was going to stick it into a gasser.

 

[GM Guy]

here is a more preffered ally to try and use http://boise.craigslist.org/pts/3310978167.html

the guy buys wrecks and junks them ,so I might give him a buzz and see how much for the electrical.

 

[THEFERMANATOR]

here is a more preffered ally to try and use http://boise.craigslist.org/pts/3310978167.html

the guy buys wrecks and junks them ,so I might give him a buzz and see how much for the electrical.

Don't forget to tach on a converter as that 8.1L converter will not work worth a crap behind a diesel. And I see from his pics he has taken teh 3 speed sensors out of it, taken the NSBU switch off as well as the shift arm. And also don't forget another $300 for trans cooler lines, and plan on another $300 for a cooler and fan set-up to keep it cool as your stock radiator cooler will NOT work with it. Building your 4L80E WILL be cheaper ANY way you slice it.