About 4L70E auto transmission

[warren c]

I like to share the info with everyone here, If it is incorrect infomations please let me know.

I have confirmed with GM that T56 and 4L60E share the same housing/case, different in length with 4L70E. But BluePrint tells me that 4L60E and 4L70E share the same case.

FFR coupe in design to install T56 transmission so in that mean I can install 4L70E with no issues,Has anyone tried to install an automatic gearbox?

I am thinking to have auto coupe on my first kit car.

Thanks for any comments or advices

[edwardb]

No. 4L60E, 4L65E and 4L70E all are similar if not exactly the same size. I have a 4L65E in my truck build and the case has 4L60E molded into it. My transmission builder said that's normal because they're the same case. Even though the internals are different. So agree with that part of your post.

I have a Tremec T-56 in my Coupe. It's not remotely the same case or size as the GM autos referenced. So I can't agree with that part. Have had both in my garage. The Gen 3 Coupe has a lot of room in the transmission tunnel compared to previous versions. The T-56 fits with ease. One of those autos might fit too, but I can't cite any experience.

4L65E before going into my truck build:

https://thefactoryfiveforum.com/attachment.php?attachmentid=136125&d=1602363776

T-56 before going into my Coupe build:

https://thefactoryfiveforum.com/attachment.php?attachmentid=97950&d=1542890511

[warren c]

Thanks for the illustrated explanation, it seems like the manual transmission will be the way to go.

[nskaats]

The T56 and 4L60E are entirely different. They do share a mount, but that's about it.

Now the 4L60E, 4L65E, 4L70E and 4L75E are identical transmissions with some internal changes. Physically the case on all of them are identical. They're all actually an electronically controlled evolution of the 700R4 trans from years ago. They can easily handle one of these cars if you feel the need to go automatic. I do have my Gen III coupe and at least one 4L60E sitting here in the shop I can use to verify measurements if need be.

[warren c]

Hi Nick,

Yes, would you please measure the fittment for me, The auto transmission is my first choice.

Thank you

[nskaats]

Hi Nick,

Yes, would you please measure the fittment for me, The auto transmission is my first choice.

Thank you

Aside from the bellhousing, the widest part of the trans is about 15.75" from the 2-4 servo to the outside of the shift selector shaft arm. The tunnel where it would pass through there is right at 17" so it will fit without issues. Height should be no issue either with a few inches of room above the trans. Lengthwise you're the same as an F-body T56 (which I'm using) so that should be easy as well.

[warren c]

can you post some pictures of you auto transmission, thanks.

[nskaats]

can you post some pictures of you auto transmission, thanks.

If you're looking for pictures of one in the car, I don't have any. I went T56 in my coupe. Just happened to have my Daytona and a 4L60E sitting here to measure. Google is your best bet if you're looking for pics of the trans itself. I don't know of anyone who has put one in a coupe yet because until recently any non-Ford powertrain required fab work that few of us were willing/able to do.