Operation Wretched Excess

[MaxPF]

So, due to an old Army injury to my left ankle I am having a rough time working the clutch in my truck. The trans itself (a completely rebuilt late aluminum top SM465 mated to a 12V Cummins) works great, but working the 13" South Bend clutch is taking it's toll...

So, I decided to swap back to an automatic. I was considering a TH400, then a 4L80E, but then I got a line on an alternative and decided to go with it. So, besides having a 12V Cummins in a K5 Blazer, I will also have this handling gear shifting duties:

Hence the name Operation Wretched Excess

 

[KansasTwister]

its got a pto drive, im interested


what trans is that mofo?

 

[us74k5]

I hear ya on the army injuries... I was really stoked to put the sm465 into my blazer when i get back from this deployment... Then i tore my meniscus in my left knee, they are going to med board me out when i get back due to the severity of it. Now I have to toss a 700r4 in there...

 

[bftank]

i see redx but iam guessing allison if ithas pto cover

 

[MaxPF]

Yup, it's an Allison 1000 out of an 8.1L truck that got rolled

 

[Babaganoosh]

Very nice, I'm very interested in seeing this swap in. I s suppose you are going to document it as you have the rest of the swap?

 

[MaxPF]

I hear ya on the army injuries... I was really stoked to put the sm465 into my blazer when i get back from this deployment... Then i tore my meniscus in my left knee, they are going to med board me out when i get back due to the severity of it. Now I have to toss a 700r4 in there...

4L80E dood. If you don't want to mess with the electronics run a 400 with an Allison TC290 or TC275 torque converter. A properly built 700 isn't a bad trans, but our trucks are heavy. 700's seem happier in Jeeps and buggies...

 

[ZukiJohn]

Soo where did you get that?? And is there another one? What t-case are you going to use ?

 

[MaxPF]

Very nice, I'm very interested in seeing this swap in. I s suppose you are going to document it as you have the rest of the swap?

Of course

Soo where did you get that?? And is there another one? What t-case are you going to use ?

Got it from a guy over in Avondale. He didn't have any others. I plan on using an NP205 behind it.

 

[cegusman]

How much was it?

 

[MaxPF]

How much was it?

$400 And it is in excellent condition as far as I can tell.

 

[bftank]

nice!

 

[cegusman]

damn you stole that thing

 

[MaxPF]

Pretty much. You can get the 5 speeds (which is what this one is) all day for a grand, and $1200-$1800 will get you a 6 speed. Finding a good one this cheap is pretty rare - rebuildable cores usually go for $500 or so...

Also, I have carefully priced out rebuild kits for the Ally, and compared it to the price of an equivalent build for a 4L80E. Amazingly, the difference (not including TC) is only about $150. They have a reputation for being super expensive, but that really isn't the case compared to any other 4-6 speed automatic. Hard parts are a bit more spendy, but I have talked to numerous builders and all of them say you pretty much never have to replace any hard parts, even when they have really fried. These pics probably explain why that is the case:

Notice the shaft support bearing visible in the pump is a true roller bearing, not a bushing like most automotive transmissions use...

Look at the size of the input assembly. The shaft is quite large. Look at the size of the P1 sun gear on the bottom of the assembly.

 

[bftank]

holy huge pic batman! it helps to see what beef that tranny has in it though. i'd love to see that compared to 700r4 innards.

what transfercase are you using? i remember their being issues adapting a tcase other than the 261/3 due to the multiple speed sensors. or is that going to be taken care of with the wiring harness?

 

[MaxPF]

holy huge pic batman! it helps to see what beef that tranny has in it though. i'd love to see that compared to 700r4 innards.

what transfercase are you using? i remember their being issues adapting a tcase other than the 261/3 due to the multiple speed sensors. or is that going to be taken care of with the wiring harness?

The output shaft is 1.475" 29 spline, which is the same as the 29 spline Dodge stuff. Guys gave already adapted 29 spline Dodge 205's to the Allison. An output speed sensor will need to be added somewhere - the Allison TCM is calibrated for a standard 40 tooth tone wheel. However, depending on the reprogrammability of the Allison TCM I may have to put it on the input of the t-case. It all depends on whether the Ally TCM can be programmed to accept a gear ratio other than that of the 26x cases. I really don't want it to go into limp mode every time I shift into low range

 

[bftank]

that would be a bummer. i would thinkk there would be someway to trick the sensor in that situation though. kinda like an electonic boost fooler does in changing the signal sent to the comp. good luck, excited to see the results.