I've installed a new Tremec TKX in my '70 Cutlass using the car's original crossmember. The car was originally an automatic. I've found it necessary to cut part of the tunnel to provide necessary clearance for the transmission despite my understanding that the TKX is supposed to fit without tunnel mods. I had the body off the car, installed new body mounts, used new 350 engine mounts with the 455 engine. The engine and transmission were installed in the frame before I put the body shell back down on the frame.

Has anyone who's installed the TKX ran into similar clearance issues or did it fit in there fine? Is there a difference between the automatic and manual transmission crossmembers? Did you need to use an aftermarket crossmember with the TKX to get it fitting properly?

 

Talked to tech support at Silver Sport Transmissions (where I bought the transmission and install kit from), apparently it's not uncommon to have to dimple or make a relief cut for the transmission to fit. There's a shim plate included with the energy suspension support mount which, although the instructions say "must" be used, the tech said it's fine to leave it out.

 

GV said I could clearance the tunnel, but I opted to cut a whole section to level out the same area you had to. Point is- nothing bolts in as they say it does.
I've never used that preload plate, either.

 

I stopped expecting that to happen ages ago, especially with this build! Sometimes you just need to dig a bit to set your mind at ease that it's not an indication of a problem elsewhere, though. In this case, it's just "normal" :-D

Good to know, thanks. I'm going to see if I can remove mine easily to get a little more clearance.

 

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Did Silver Sport Transmissions recommend a new cross member? It looks like if the trans was down 1/2" to 1" inches it might clear better.
Probably should also get a drive shaft angle measuring tool and check your driveshaft angles.

 

No, but that would have been my next question if the tech hadn't indicated that this wasn't unusual. Pulling that shim out might be the difference.

Definitely in the plan...I have a couple friends with them (and the knowledge to use them!). Still too early for that, have a lot of weight to add up front (fenders, hood, rad, etc) and inside (carpet, sound mat, seats)...don't even have a new drive shaft yet. The angle may lead to more changes but for now it would just be a guessing game.

 

I used the TKX for my recent build. No cutting of the tunnel. Perfect fit.

 

Yeah, I read through your build a few times and didn't recall any fitment issues like that. Did you use the Energy Suspension mount?

 

2 other things to note here:
Energy makes a short mount. You may want to check the model number used vs all the ones available.

Were the body bushings replaced? Those play a huge part in trans to tunnel clearance as well.

 

All my trans components were purchased as a kit through Modern Driveline. I used the ones they provided and also the factory cross member. Everything lined up fine as I recall. I can take some pics if that would be helpful once I get back from being out of town.

 

Yes, all new body bushings and engine mounts. I'll have a look at the other mount options. The one I used was part of the package provided by Silver Sport for the install in a 70 Cutlass for whatever that might be worth!

 

Thanks, it would be interesting to see how much space you wound up with there.

 

3.1158G is the short mount in black

Sorry for the weird font.... phone paste things

 

Thanks for the PN...that is actually the one they sent me or at least that's what the invoice says.

 

As mentioned, the engine and transmission were installed in the frame before I lowered the body back onto it. We later realized that the body was resting on the top of the tail end of the transmission. Body mount bolts have not been torqued yet.





I cut a relief opening on the tunnel and got the needed clearance.




I had been hoping it would slip in without drama as had been advertised but at the same time I wasn't the least bit surprised that it didn't. After talking to tech support at Silver Sport and being assured that they don't always fit perfectly and my situation is pretty common, plus everyone's input in this thread, I removed the shim (about 1/8" thick) that was included in the Energy Suspension mount. That settled the tail end down a little more although it still looks like some dimpling or other clearance solution would be needed in my case.






I think I can live with this. I'll be putting a cover over the opening just to keep the tunnel sealed. With no driveshaft yet I haven't checked the angles which may wind up leading to some further adjustments. I've got a UMI tubular rear control arm set but they're not adjustable...I'll cross that bridge when I get there!

 

"Slight dimpling with a hammer" Sure!

 

I can try and send some pics soon. I definitely didn't cut into the floor pan at all. I'm out of town for a few more days and will try when I return.