extremely hot trans tunnel
 

I just recently got my first (and hopefully only) FD and I am having an issue with the transmission tunnel being extremely hot. There is just so much heat emenating from the transmission tunnel that it makes being in the car very uncomfortable. The shifter gets really hot and so does the plastic covering. This doesn't seem normal, but I wanted to get some input from you guys before making any conclusions.

Does anyone know of any heat retardant material that I can place under the carpet to help the situation out?

I'll post more about my 7 and the rebuild on another thread :)

-Alberto

I'm guessing you have an automatic? FYI, this was the first symptom I had before the tranny went out. At the least I would take the care to a trans shop and have them change the trans fluid NOW. Use synthetic. Have them evaluate the look and smell of the fluid they remove (check to see if it's burnt smelling, discolored, etc.). Check to make sure that your trans cooler (right front) is not badly damaged, or make sure it's present. Heat deadening material does not solve the problem and would actually make things worse as heat would build up even more where the trouble spot is. Transmission heat in automatics has been linked to rear rotor failure.

Even if you don't have an auto, change the gear oil now to synthetic.

Sorry, I should have included some more details about the car:
- 5 speed
- 93 Touring
- rebuilt motor with 400 miles
- SS downpipe
- RB cat back
- stock cat
- Blitz SMIC
- stock twins
- big radiator (Koyo?)
- vented hood
- Power FC
- stock air box with cut out bottom (like in adam_c's thread)
- B&M short shifter
- car has never been hit

I was planning on changing to Redline MTL tonight, but I don't think that is going to do the trick. I could be wrong and hopefully I am.

The car does shift reasonably well. It is a bit notchy when cold and driving around town, but feels better on the highway.

In addition to changing the Trans oil to a good synthetic, make sure the Heat Shield around the Catalytic converter is intact and in place. Also wrap the Down Pipe w/ ThermoTec (or other brand) insulating header wrap.

Hmm. Didn't think about the cat... The heat shield around the cat is there. However, the heat shielding on the bottom side of the cat is... shall we say a little crushed.

I bought the stock cat from coop who shipped the cat to me in small box w/o any packing material so the heat shielding was all a bit crushed when I got it. Especially on the bottom side.

I wonder if the cat could be the culprit? Would it heat things up like this?

When I first got my FD, the Mazda dealer that I got it from put the wrong kind of oil in the tranny, and it even made my shifter hot. When I went to get the oil changed I was told it was the wrong fluid and had it replaced and it has been cool ever since.
Good Luck!

I've had good results with Mobil1 70w90 Synth in the tranny and diff :)

I'm doing the MTL tonight then. I've been using Redline MTL since my VW days back in 88. I experimented a few times with my VWs and Turbo IIs using Amsoil, Mobil 1 and others and got smoother shifts from the MTL.

I'll report back when its done. Thanks fellas.

its normal for the transmission tunnel to get warm. do you have A/C on? when my A/C went out last year i noticed the transmission was hot inside the car and i wanted to coat the sidewall with heatshielding. with the A/C on it is not noticeable though so i havent done that since fixing the A/C.

its not warm - its hot, very hot. a/c is off as its not charged yet. we shall see manana.

it depends but mine gets freaking hot too.......its normal sorta

I've owned two 3rd gens w/ 5spds. On both cars, a noticable amount of heat radiates off the transmissions into the interior.

No no, ITs because of how your short shifter was installed, I guarnTEE it.

When I installed mine, the big rubber encahsed metal shield that goes over the trans tunnel opening, was not flush with the frame, so hot air from the trans and motor just vented right up into there and started to warm teh shit out of everything.

I went back in there and made it as flush as I can , and put the insulation that was in there with the stock shifter back in, as I didnt have it in there before.

Now the entire area is just warm to the touch in 80F weather.

goodfellas, i meant to make a post but never did and you answered my question. i can get the mobil1 syn 75w90 really cheap and i was going to start using that. the redline is just too much. i would like to change the diff oil on a regular basis. the kazz reccomends it why shouldnt we did it say every 10K miles on the stock diff
kris

You could have an oil leak in the trans. When it's too low or empty it will get hot. Change to synthetic and check for leaks.

You could have a cloged Cat' which could be radiating heat. When mine went bad on my CRX it glowed red like a bbq charcoal!

On my Honda the short shifter sticks down lower then OEM and is barely above the exaust piping and the shifter and handle get hot after about a 1/2 hour. I don't remember where the shifter is located under the 7. I don't have a short shifter on my 7 so it doesn't get hot.

I changed the tranny and diff oil to Redline MTL and 75/90 respectively yesterday. It is *SO MUCH BETTER* now!!!!

The car shifts so much smoother, the aluminum shift knob is much cooler (I can actually touch it now), car seems quieter. Did I mention how much smoother the shifting is?! Huge difference! I had forgotten how well MTL worked. The tranny tunnel is cooler to the touch now also. Sweet :)

Rx-7$4$me - you got a good point there too. I'll have to check that out too. Maybe the previous owner didn't reinstall that stuff properly.

Thanks fellas.

In a previous post I mentioned that both my current and previous 3rd gen generated a noticable amount of heat from the transmission tunnel into the interior.

Since that post, I just switched to synthetic in the tranny and swapped my precat for a downpipe. No more warm transmission tunnel. Also, no more boost problems. My clogged precat caused me to have random loss of boost.

am i missing something here?
 

Still running a bit hot. Not as bad though. Is there supposed to be any heat shielding or sound deadening material here? I believe my old Turbo II had some thick sound deadening material here.

The situation arises when I drive from Long Island to NYC to NJ. The drive to NYC is fine, cruising along the highway. It starts to get quite a bit warmer as I make my way through the city to pick up my woman. There I'm driving slow 2nd gear light to light for 20 minutes. That is where it starts to get uncomfortable. The foot wells get hot and the tranny tunnel radiates heat. I'll do more highway driving out to NJ and it just never really seems to cool down.

Hah! theres your problem man! Theres supposed to be a metal pieced overlayed in rubber, that goes across that opening to the 4 bolts sticking out of the corners. It keeps alot of the heat in, also there is a bit of insulation supposed to go on top of that as well!

Re: am i missing something here?
 

Yes. The stock shifter has a thick rubber mat and then a couple layers of thick felt insulation underneath the shift boot.

My tunnel is warm on the sides when driving, but I never have anything I would call hot or uncomfortable in the shifter area. I still have the stock shifter.

Do as Rx-7$4$me says and your problem will go away.

ooops wrong pic. here is the one that i meant to upload. is there something missing?

Nothing missing there sept for a bit of insulation that goes over that. ITs just like a slab of junk, kinda like stuff in the firewall.

It sounds like your car's previous owner had the main cat section removed.

When I had my stock cat center section removed (replaced w/Bonez), a huge piece of sheet metal above and attached to the main cat comes off with it. This sheet metal is what insulates the tranny tunnel from the main cat in stock configuration.

I had a local shop remove the upper sheet metal from the old cat, and attached it directly to the tranny tunnel with sheet metal screws and a layer of aluminized heat barrier cloth between the sheet metal and tranny tunnel.

Additional heat will be felt thru the firewall from a stainless downpipe unless your downpipe is wrapped or jet-coated. I had mine wrapped.

Heat problems just like yours were solved completely with these changes.

I got some possible valueable info for you

Check the rubber gaskets to make sure they are intack since you have a BM Short Shifter. VERY LIKELY, that would make all that happen

ALSO change the fluid, like mentioned before.. That will help anyway

I guess I should have read all the way down hehe

Yeah those rubber boots are a little loose on that shifter since the stock shifter, C's, Mazdaspeed all get big at the bottom to strength, and will tighten up that hole to prevent heat.

Figured the tranny oil change would help.hehe

OK, I had this problem with my last FD, and also my current one, until I did this: Use Thermo Tec header wrap to wrap the exhaust system from the beginning of the downpipe to the end of the midpipe, before the last section of the exhaust. I did this, and the difference is night and day, the comparision will be remarkable once you do it, and do it properly, by this I mean installing the wrap fully around the exhaust and using good clamps, so that there's no spaces, with the exception of where the ends meet. The reason for this is because the exhaust obviously runs next to the transmission and under the passenger side, so if you stop heat from coming off of the exhaust till it's behind the passenger compartment you won't get that heat into the interior anymore. Try it, I guarantee you'll be happy with the results. Also the reason that this doesn't happen with stock exhaust is because the entire stock system comes with heat shields from the factory to prevent this, so basically you have to do the same thing to the aftermarket stuff, just with the header wrap.

NedM - yeah the previous owner had a mid-pipe. I replaced it with a stock cat. It does have a heat shield above the cat. It is attached to the cat actually. This is probably a long shot, but do you (or anyone else) have a pic of what that looks heat shield looks like?

Somehow, I don't think I will be able to find one quickly or easily enough. I just ordered some thermo-tec for the downpipe and some DEI aluminized heat screen that I'll attach to the tranny tunnel up top. Oil is already changed to MTL (made a huge difference actually).

I think this should cover it. Thanks a lot everyone.

If your heat shield over the cat is attached it's almost certainly the stock one. Make sure you apply the aluminized heat fabric with the shiny side facing but not touching the cat, and it should make a big difference. Also, I was able to fit a small piece on the firewall near the downpipe and that helped too.

Great info.
 

I have the exact same problem, I live in Miami, and to top it all off my a/c is broken, my car is an inferno to drive in the daytime. I am going to do all of that hopefully it eliminates some of the heat.

I feel your pain...

Solution seems to be:
- Make sure the insulation is intact below the shift boot console (about $2 from Malloy)
- Redline MTL
- Wrap the downpipe in ThermoTec header wrap
- Use some kind of heat reflecting covering (like DEI heat screen) on firewall/floorboard or tranny tunnel

both of these can be found at summitracing.com

Mine should get done this weekend. I'm sick of listening to my girl friend bitch about how hot it gets in the car. It is negatively effecting my sex life. ;(

update
 

Just wanted to update this thread with a final status.

The first thing I did was change to Redline MTL. It made a huge difference in the shift feel and the heat that I felt at the shift knob and shift lever. Definitely cooled it down by more than a few degrees.

It was still too hot so I got the stock leather knob and that made it a little more tolerable on the hand. However, there was still a lot of heat radiating from the tranny tunnel and from under the middle console.

The felt sound deadening piece that I got from Malloy didn't help as much as I would have helped. It is just a 5"X5" square about 1" thick. Plus it doesn't really fit well with an aftermarket short shift kit.

The problem is that there is a huge square gap around where the shifter comes in. Check the first pic so see what I mean. The heat just rises right through that opening.

I got the DEI Heat Screen from Summit last week and installed. This helped the most! I took out the entire center/middle console thing and cut a sheet of the Heat Screen to sit over the tunnel from the front of the shifter to around where the back of my seat is. I cut a hole so that I could place the sheet over the shifter and shift mechanism. Then I sliced an opening in the carpet under the center console and pushed the Heat Screen stuff under the carpet as far as it could go. This effectively sealed off that huge gap that was allowing the heat to come in. It sits flush against the tranny tunnel metal.

Then I forced the sound deadening felt strip over the shifter and installed the black rubberized thing over it securing the black rubber thing with the 4 10mm bolts.

This made it much more tolerable as there wasn't nearly as much heat making into the cabin anymore. However, the car still got hot after long stop and go drives like when I'm making my way through the city over to Jersey. I wrapped my downpipe a couple of days ago (after installing the Heat Screen stuff) and that was the icing on the cake!

I was extremely surprised how much of a difference wrapping the downpipe made. The Thermal Header Wrap stuff really does help 'pull' the heat out of the engine compartment. The car does not heat up and heat soak as much with the Header Wrap stuff especially when driving around at city speeds.

Highly recommend the above to anyone in warm climates or w/o air conditioning like I have been suffering through. I was going to use that Heat Screen stuff on the firewall and underside of trans tunnel, but I don't think I even need it anymore.

Thats it for now. Cheers :D

damn that was a long post...

Mine gets hot too but I removed all my heat shielding when I put my bitch on her last diet.