NP246 6 bolt to 4L60E 4 bolt

[Runerock]

Hi. So I have a 99 2dr Tahoe 4X4 that is getting a new transmission. Summit sold me one that they swore was the correct one after I asked why the bell housing was different. I ended up going to a yard and pulling the correct dust shield cover. My old one just has a plate and a bell housing that goes all the way around. As I'm pulling my NP246 I notice it has 6 bolts holding it to the transmission, but the new transmission only has 4 bolt holes for attachment is there an adapter or do I just need to send this transmission back? Everything else as far as electronics, brackets, shields looks right. Looked at Advance Adapters page and it is difficult to pick the correct one, if there is one. Thanks in advance for any help. I've been lurking for months finding answers and info without posting any questions up until now. You all have been super helpful without even knowing it.

 

[GoToGuy]

If there was an adapter, you would already have installed on yours. If your received transfer case isn't the same as what you have, either yours has been swapped out from original or you received the wrong one. Whether ordered incorrect or shipped incorrect to be determined. Does your OE transmission have the removable bell housing. Not sure when they started installing those models.
You could ask Nick at " Nicks transmissions " he's a new member sponsor. Verify by RPO codes what drivetrain yours was built with.
Just check with what GM would list for parts, enter your VIN at " GM Parts Giant .com " select transmission see what there part numbers are for your short Tahoe. By entering your Tahoe by VIN it will know it's a 2 door Tahoe, and results will be specifically for 2 door Tahoe. ( I have a 4 door)

 

[Runerock]

I have some inquires out on possible adapters and will look into your suggestions. Neither the old or new bellhousing is removable. Looking around at the salvage yard almost all the 4L60Es had my originals style of 6 bolts for attaching and flat shields. I'm going to head back there tomorrow and see if the truck I took the larger shield from has what I need. Thanks for the reply

 

[Runerock]

Thinking about it, I'm just assuming they had 6 bolts between transfer case and transmission, but most of the gmt400s there had bellhousings like mine with full housings and flat shields.

 

[Hipster]

Thinking about it, I'm just assuming they had 6 bolts between transfer case and transmission, but most of the gmt400s there had bellhousings like mine with full housings and flat shields.

I would send the trans back, adapters add thickmess, spline counts, engagement depths, etc.

 

[b454rat]

Need to get an older adaptor. I ran into this when I had my 96 Yukon. Motor/trans were toast when bought it. I can't remember what year the trans was, but was off by 1 year. the earlier 4L60s used 4 bolt on the trans side, then when GM screwed with things they went to 6.

 

[Nad_Yvalhosert]

The tranny mount is the adaptor. One side has 4 holes, the other has 6, and the bottom has 2 for the rubber mount.

 

[Nad_Yvalhosert]

As for the tranny, the 4L60 does have 1 piece belhousing (with a bolt on torque converter cover) and a 2 piece case (with a sheetmetal plate between the engine and trans).
Generally, the C/K-series got the 1 piece and the S/T series got the 2.
I would send the 2 piece back as they likely are not built with the additional internal clutches that the V8 needs.

 

[b454rat]

That’s not 100% correct, IIRC 98-up all had the 2 piece trans, meaning can unbolt the bell from trans. This is one of the reasons they say 98-2000 is only trans that will work…..

 

[Supercharged111]

Why not just swap the t-case adapter over from the old trans?