700r from 89 Vandura questions

[NickTransmissions]

I have a 6L90E from a Duramax with only 24K miles on it. Will be doing the same with my L31 based 383. I will be going to a 58x setup, DBW, and an E67 PCM with a modified late model Express engine harness to run it all. Just have not had time to dive off into it all yet.

Another thing that is rarely mentioned is the 4L60E transmission mounting point changed when the 4L60E became a 2 piece bellhousing even in the SBC era. Years ago when I put the 4L65E built for the older 350 as you previously mentioned into my 97 Express van I had to scrounge up a junkyard 1998-2002 1500 van aka 6 lug 2500 van crossmember to get the newer style case mounted into place. The mounting point moved and the crossmember on the vans bolt to brackets welded to the frame. 96-97 thus had a different crossmember than 98-02. I had to fabricate my own modified crossmember for the 4L85E swap later. My buddy also put a 99 Tahoe transmission in his 97 extended cab years ago, had to move the crossmember back and drill new holes in his frame.

Yep, they changed up the rear of the case from the old 4-bolt ext housing to the 6-bolt and moved the rear x-member-to-trans mount from the case to the ext housing (though some of the pass cars w/one piece cases had the rear x member mount on the ext housing, as you know).

As to why it's not often discussed, my guess is a combination of the relative ease of adapting cross members coupled w/the growing number of aftermarket companies that have purpose-built cross members for different vehicle-transmission combos and their respective mounting locations. Not surprising, given how popular engine and transmission resto-swaps have become these past twenty years or so..

 

[L31MaxExpress]

Yep, they changed up the rear of the case from the old 4-bolt ext housing to the 6-bolt and moved the rear x-member-to-trans mount from the case to the ext housing (though some of the pass cars w/one piece cases had the rear x member mount on the ext housing, as you know).

As to why it's not often discussed, my guess is a combination of the relative ease of adapting cross members coupled w/the growing number of aftermarket companies that have purpose-built cross members for different vehicle-transmission combos and their respective mounting locations. Not surprising, given how popular engine and transmission resto-swaps have become these past twenty years or so..

Some of the earlier 4 bolt extension housing 700r4/4L60E applications had the mount basically at the end of the tailshaft as well. My 83 G20 was like this and I had to use a mid 90s B-car 4L60E extension housing to mount a 4L60E into it.

 

[NickTransmissions]

Some of the earlier 4 bolt extension housing 700r4/4L60E applications had the mount basically at the end of the tailshaft as well. My 83 G20 was like this and I had to use a mid 90s B-car 4L60E extension housing to mount a 4L60E into it.

Yep, extension housing = tail shaft. The Caprices, Impalas had them and the Fbodies had theirs with through-bolt locations cast for the torque arms, which carried forward to the two piece cases. The vette cases began to get strange with the torque tube set ups, not exactly sure when that started...

 

[L31MaxExpress]

Yep, extension housing = tail shaft. The Caprices, Impalas had them and the Fbodies had theirs with through-bolt locations cast for the torque arms, which carried forward to the two piece cases. The vette cases began to get strange with the torque tube set ups, not exactly sure when that started...

97 MY with the C5 introduction. The earlier Vette 700r4/4L60E was like 1" shorter too, never really understood that one.

Done the F-car stuff too. Torque strut was always a PITA.

 

[NickTransmissions]

97 MY with the C5 introduction. The earlier Vette 700r4/4L60E was like 1" shorter too, never really understood that one.

Done the F-car stuff too. Torque strut was always a PITA.

Makes sense that the torque tube was intro'd in lock step with the LS1 in the vettes.

 

[Scooterwrench]

Just throwing this out there but there is another tail housing that wasn't mentioned. The one on my '91 1/2 ton has no mounting holes on it. The tranny mount is on the main case right in front of the tail housing.

 

[tayto]

Just throwing this out there but there is another tail housing that wasn't mentioned. The one on my '91 1/2 ton has no mounting holes on it. The tranny mount is on the main case right in front of the tail housing.

that's the standard tail shaft, probably why it wasn't mentioned.

 

[Erik the Awful]

For the longest time I was told that an older engine would not bolt to a 6L80E without the GM bellhousing spacer or a custom built converter and 97Centurion proved that wrong too.

@97Centurion was told the same thing. He decided to try it anyways and discovered that there are a lot of people speaking out of their butt.

 

[97Centurion]

L31/6L80e still holding strong!

 

[L31MaxExpress]

L31/6L80e still holding strong!

Have you had to lay into it yet at any point? If so how did it get up and go compared to the 4L60E?