Hey all. Im building a sled pulling truck using an lq4 and 4l80e combo, and i was hoping to get some help interpreting/understanding one of the class rules on transmission protection...

Heres the rule:
"2.All automotive type engines with bellhousings and clutch will run a full block plate, either a unit commercially available, or minimum 3/16” steel or minimum 1⁄4 inch aluminum with six 3/8” Grade #5 bolts evenly spaced on the bottom of the bellhousing and a blanket for automatics from front to back or short blanket on bellhousing with 3/16” steel shield over body of transmission. SFI composite transmission cover allowed. Standard transmission must have a steel bellhousing, complete with commercially available or 3/16” block plate."

now ive talked with an existing class member and he said he used a trans blanket for an allison (duramax) trans as it covers both the trans and t case. However the rule dosent say anything about t case protection.
He sent me the part number of the blanket he uses (801191-AS) and its $556. Im on a tighter budget than him and i would like to keep it cheaper. Summit makes a blanket SUM-590300 for $155 however i would assume its much smaller than the allison one. What are your thoughts/interpretations of this?

 

The risk is that a driveline failure will allow the internals to overspeed. The trans blanket will contain the parts from going into the crowd, but they will probably still make a mess of your floor pan.

Since weight is not a huge issue for pulling rigs, how about a build a 3/16" steel scatter shield into your floor? You could go front to back and the materials would cost less than the summit branded trans blankie.

That being said, I use the jeg-branded version of that same blanket & it only goes cover the main case of the transmission not the bellhousing. The bell is an SFI piece as mandated by nhra so i have to shell out for the bell no matter what.

and as I've been told by many high end builders, a $2500 reid case is cheaper than a wooden foot.

 

Where does the Driver sit in relation to the Transmission?

For example, In my Funny Car, the Driver straddles the Transmission.
The Titanium Bell-Housing and Kevlar Ballistics Bag that wraps the Transmission is usually about $6,500 every 2-Years.

I have seen guys in testing go without the Titanium Bell-Housing and Bag...
And have unfortunately seen legs get nearly clean cut off...
As well as some reproductive organs!

 

currently i sit left of the trans (its a 2004 silverado 2500, so left hand drive like a regular truck). My class is a small tire/small motor class (500cube max, 31" tire max, 5600lb max) but i guess the danger of exploding driveline is still just as much of an issue. Ive talked with a few pullers in my class and even the class rep and i think i can get away with the blanket on the bellhousing and a 3/8" steel shield on the top between the trans tunnel and transmission. Just need to get on the drawing board about designs.

You funny car guys are a different breed. I dont have the guts for that 😝

 

I can understand the issue about exploding driveline (even at the small motor/small tire class im in). Would it be better to reinforce the trans tunnel/floorpan? Or just build a shield that sits in between that can be bolted in? I need to look at how it would work as the 4l80e is cable shifted. I spoke with the class rep today, he said i can get away with the blanket on the bellhousing and then a steel shield that "covers the top/sides of the transmission and runs the whole length of it". Again didnt really clarify about the transfercase issue. But it sits in relation back and to the right of me so maybe thats not a factor? I dont know exactly how strong GM set out to build their floorpans 😂