Novak Conversions Jeep Wrangler TJ engine mounts

Switching from Straight Pipe to Muffler exhaust system is messing up my transmission?

YoRelax

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Feb 16, 2019
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Location
Winter Park Florida
I bought my 2006 Jeep LJ from a buddy not too long ago and he has it straight piped. After a couple of months of daily driving the droning got to me. Found a 40 series Flowmaster muffler on Facebook and bought it. Cut a piece out of the pipe, used some adapters and now it was bearable.......

I had my transmission rebuilt about a month ago and it was riding PERFECTLY. However, as soon as I slapped the muffler on it shifts very hard and sometimes seems to struggle to find the perfect time to shift. It’s not smooth at all! Do I switch back to straight pipe or is there something I forgot to do???
 
Wow, I really can't think of any connection between an exhaust system and the way your tranny shifts; that is, short of adding an exhaust that totally screws up the way the engine runs.

I know it's sounds odd, but I think your tranny shift problems may be completely unrelated to the exhaust mod...
UNLESS...question: Did you put on the exhaust mod or did you have it done at a shop? Asking because, if the shift problems seemed to exactly coincide with the exhaust change, one wonders if something was inadvertently done to the tranny during installation.

In general, if it were me, I'd take it back to the transmission shop and tell them it's suddenly shifting funny...and keep the exhaust change to yourself for now.
 
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Did you possibly remove the skid plate without supporting the trans during the exhaust work?

Idk much about autos or if that could do damage that matches your symptoms.
 
I did the instal myself and I had no idea the weight of the tranny was supporrred by the skid plate. What’s the worst that could have happened if the tranny wasn’t supported properly by the skid plate??
 
Ugh...gonna have to defer to those with an automatic for their thoughts but do check the following:
Transmission fluid level...in case a line was damaged.
Speaking of which, inspect the cooling lines all the way up to the radiator for any kinks or breaks.
Since the tranny was being held up by the engine, check your motor mounts, any electrical connections that come from above. Also, check the suggestions in this thread.
 
What’s the worst that could have happened if the tranny wasn’t supported properly by the skid plate??

The worst? The engine mounts break off the block while you are under the Jeep dropping the whole thing on your head. Probably the worst I can think of but I'm not too creative.

I'd probably take a look at the wiring, something probably got pinched or pulled like TJ Hunnicutt said. You might take a close look at the back of the engine at the firewall where the valve cover is, the whole package can rest on that rear harness when you do that.
 
Novak Conversions Jeep Wrangler TJ engine mounts