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pcm for 4t65e runing 4t65HD?

Z34Phoenix

Z34Phoenix

Florida Tuner
I know a PCM for a 4t65HD will run a 4t65e but will the opposite work?

i want to know for sure if people have tried this, as i am considering a swap and the only file i can use was made for a 4t65e and never had an HD option. i know that people can rung a bin for a L67 and it run their non HD trany. but will say a L36 bin run a 4t65HD?

and yes i know the gear ratio will be diff. i can adjust for that. i am currently running a gear swap from 3.43's to 3.73's in my 4t60e.
 


like said im not worried about the gear ratios... yes the normal non HD 4t65e is is a 3.29 some i read somewhere are even 3.05? and i know the HD's are 2.93.

I am looking to run a 97 Z34 engine, PCM, and harness so that i can run a 4t65 on my DOHC engine. there was never an option for an HD trany with that engine...

this is why i want to make sure a bin intended for a non HD trany will run a HD trany.
 
Just change the gear ratio... The only thing HD really does is a different size axle and a different Diff/housing. PCM doesn't care about that.

If it helps, no mention of pcm reprogramming in this...
ZZ Performance
 
Ok
For the gear swap I know the sprocket ratio needs changed. Shift tables obviously. Are u saying the actual speed sensor or the rev per mile in the bin?
 


The only difference your pcm will see is the gear ratio. The only HD diffs are 3.29 ratio. Which when combined with the drive/drive sprockets are how you get to the 2.93 or 3.29 ratios.

HD chainsets are always 1.21:1
Non HD sets are always 1:1
 
It could.

See 4T65's are all basically the same. The differences are the drive/driven gearsets. The size of the diff HD or not (and ratio of planetaries/input sun gear) and the size of the output shaft.

So if you choose to get a gearset to make a 3.69, you'll end up with a drive/driven ratio different from either of the stock ones available from the factory. Then addin the 3.29 HD diff or a 3.29 nonHD diff to give you a final result of 3.69's.

It's the combo of drive/driven ratio plus diff ratio that will get you to 3.69. In this case, since HD and non-hd both have a 3.29 diff ratio available you could make a nonHD 3.69 trans.

Don't let yourself get hung up on the HD ve non-HD wording. The only real difference is ratio at the drive/driven gears (input side) and the size of the differential.
 
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