I have a couple questions about my swapped transmission - Honda Prelude Forum

SoCalBA8 · 04-20-2011, 04:10 PM

Hey guys, I have a 94 SI, despite what my screen name says LOL, w/ the 2.3L H23A Non VTEC and it had the MP1A auto trans in it. The first gear started going out on me so I had a shop swap in a MP6A auto trans in its place, but now instead of having a rough shift from 1st to 2nd gear and 1st gear slipping when I am accelerating around corners with my MP1A, The MP6A shifts perfect until the car warms up then anytime it down shifts in any gear, it intermittently shifts pretty rough. The same TCM was used from my MP1A, the mechanics said that they used Honda ATF only, and everything seems hooked up right to my knowledge. The fluid itself is at the right level and doesn't smell burnt or have metal shavings in it and the transmission only has about 40,000 miles on it.

I have warranty on it from the mechanics, but they are very unprofessional and they take forever to do the simplest of tasks so, I am trying to avoid bringing it back there if I can. PM me if you want the full story on the shop.

The questions that I have are:
Should it be okay to use the MP1A TCM with the MP6A?

My concern is since the TCM tells the trans when to shift, are the gear ratios that far off between the two transmissions that the TCM is possibly causing the issue?

Also, I noticed that when the car shifts from first to second, the car bogs a little like it is dropping too far in RPMs before second gear allows the car to "take off." I'm not trying to launch my car or race or anything. It happens under normal driving conditions. My gas pedal also feels harder to press than before the trans was swapped as well.

I see that the throttle cable and shift linkage cable appears to be the same cable, is that cable the possible cause of my issue? Does that cable need to be lubricated or can it be adjusted to hopefully fix my issues?

Any help or advice would be much appreciated. To stop most of you in your tracks right here, switching to a manual trans is not an option due to high school sports injuries to my left leg and ankle.

BB4swagg · 04-23-2011, 01:36 AM

Hey socalba8, it seems like were having the same issues. just did a h22a swap in my 92 lude and also a auto tranny replace. ordered it from jdmenginedepot. anyways im using the same tcm as the tranny before and my step dad got me genuine honda tranny fluid from his work. i dont understand what the issue is with the down shifting. maybe the cable needs adjusted? idk, i tried but it didnt seem to work any.

minilogoguy18 · 04-23-2011, 05:04 PM

Auto transmissions suck, they all fail, only a matter of time. One reason why it runs better cold than warm is the viscosity of the fluid changes and becomes thinner when warm. If the clutch packs are worn the thinner fluid will let it slip. The shift points is probably because of using the wrong TCM.

If your fluid in the trans looks like dirty oil then that thing is probably F'ed, changing the fluid will only make it even worse. You need to see if that shop is warrantying the trans or just the work or both and get something better in there. Also get the right TCM.

BB4swagg · 04-23-2011, 11:57 PM

i figured it would be the tcm for me. when you get on it in d4 it wont hit vtec. you have to manualy shift it down to the gear you want to hit vtec in. its kinda annoying. where would i go about buying a tcm from? also how do you find out which tranny you have?

minilogoguy18 · 04-24-2011, 08:25 AM

Code is on a white sticker next to the starter on the case. I can understand the OP not swapping to manual by why are you messing with a POS auto? Do you not realize just how much faster the car will be just by swapping to 5 speed?

BB4swagg · 04-25-2011, 01:28 AM

well for me i decided to just replace the auto tranny because it was only 200 bucks as for the manual it was 800. while i was doing the engine swap to the h22a the person towing the prelude snaped the parking crawl in my other auto tranny. it was pretty ****ty. and having spent almost 4 grand on **** already, it seemed like the obvious choice, being on a budget that was already exceeded. fml lol

SoCalBA8 · 04-25-2011, 02:43 PM

The fluid in my tranny is clean with a red tint like it should be. There are mo metal shavings and it doesn't smell burnt. I never got to see what the old fluid looked like in my new tranny since it was already out of the car it came out of. For some reason, my tranny didn't really down shift rough all weekend or on my way to work today, so I am going to monitor it for the next couple of days and see if it does it again and if it does, I am bringing it back to the shop to get checked out.

The only problem is, I should have never got my work done at the shop that I got it done at. The price was right and everything seemed right in the beginning, but when it got to the point where the "mechanics" were asking me for pointers on getting off a free spinning stud and a stuck cv axle, it made me wish I still had credit so I could have just done a charge back rather than have to stick it out since I paid cash.

BB4swagg · 04-28-2011, 05:46 PM

i now know the answer to your problem.
you need to get the right tcu for your transmission.
the trans number will be on your trans case, right below your starter.
call jdmenginedepot there number is on thier site jdmenginedepot.com
tell them the part number and order the tcu. itll come in a pair with a ecu for 70 bucks.

ill post the link to an instuctional on how to install the tcu and the wires youll need.

BB4swagg · 04-28-2011, 05:48 PM

Installation of H22A TCU? [Archive] - Accordingly Done

BB4swagg · 04-28-2011, 05:50 PM

i understand that your situation is abit different than mine but im pretty sure its about the same thing. i hope this helps you.

SoCalBA8 · 04-29-2011, 11:28 AM

Thanks for posting up the info BB4swagg. I'll run this info and the instructions in the link by my roommates, who know even more about this stuff than I do, and see what they think.

BB4swagg · 04-29-2011, 11:58 PM

yeah np. my tcu and ecu is on its way. if your tranny is the usdm one and not the jdm one you should have to run any extra wires. just unplug both ecu and tcu and plug in the new ones i do believe. lemme know how everything works out for you.

you can usually find all the answered to your questions in the online froms.
no just this one but others too.