ST185 transmission swap into ST165?

wound3S

New member
The transmission in my ST165 tends to grind going into third. A friend of mine offered his JDM ST185 transmission that he got with a 3S-GTE that went into an MR2. Is this pretty much a direct replacement? I couldn't find anything by searching.
Thanks!
 

88st165

New member
Yeah it will bolt right up.

Speedo cable might be different or maybe thats only an issue with the 205 trans. I believe that could possibly be the only issue. The 165 axles should work with the 185 trans no problem.
 

wound3S

New member
Good point. I remember with MR2s the E153 trannies switch from mechanical to electric speedometer sensors in 1993, so if that was the same with alltracs then I'll need to switch out the old one. IIRC that was not too big of a deal. Thanks for the info.
 

All-Trac Dude08

New member
Well my speedo cable in my st165 broke so I went to the junkyard and got on of a st182. The only difference was that it was about an inch longer, so I don't think that the st185 cable will be too different.
 

Shaggz00

Active member
The biggest difference when it comes to swapping, is that you must use the 165 top trans mount. The 185 mount is too wide. Using the 185 rear mount is ok, and cool because it has that little extra brace for whatever reason. Also, the 165 axles WILL work, in case there is any doubt.
 

WideFNopen

New member
I hate to be the bearer of bad news but you are going to miss your st165 first gear. The 185 first is quite a bit longer.
 

Shaggz00

Active member
WideFNopen":3kczf3n6 said:
I hate to be the bearer of bad news but you are going to miss your st165 first gear. The 185 first is quite a bit longer.

I went from 165 to 185 and back to 165 (only because the 185 trans had problems) and I miss the 185 1st gear! haha. I had forgotten how short the 165 gear is... :(
 

wound3S

New member
Uhh, the number i have are:
chassis first.final.overall first gear ratio
ST165: 3.583 3.933 14.092
ST185: 3.384 4.285 14.500

Unless my numbers are wrong the ST185 first gear will be about 3% shorter.
 

WideFNopen

New member
wound3S":23rwxo5a said:
Uhh, the number i have are:
chassis first.final.overall first gear ratio
ST165: 3.583 3.933 14.092
ST185: 3.384 4.285 14.500

Unless my numbers are wrong the ST185 first gear will be about 3% shorter.

I see what you are saying now that I learned to read.

Does the center diff determine the final drive?

Now that I have thought about it, I have a 185 trans with a 165 center diff. If the diff determines the final drive that would explain why I have a longer first now.
 

RedCelicaTRD

Moderator
RC, Euro and I've heard Autrailian all have the 3.9 final.

On a side note, RC=ST165 w/ 3.9 final. I've always just thought that was interesting.
 

wound3S

New member
The ST165 final drive has been used by several MR2 Turbo owners. I found this on the MR2OC board:

"3.933 Shaft, Output_______ 33321-20120
3.933 Gear, Ring__________ 41221-12240
3.933 Gear, Oil Pump____ 33407-12011


These part numbers are from an ST165 (88-89 All Trac)"

The MR2T also has the .731 fifth gear like all all-tracs but will rev at about 3100rpm at 60mph IIRC... my ST165 is well below 3000 with about the same tire size.

Personally I love having the wide, long gearing. It's great. I'm used to driving an '85 MR2 which revs about 3300 at 60mph, though :)
 

RedCelicaTRD

Moderator
People over at the MR2 boards have been reading the same wrong information for years. The 3.9 final drive was never avaliable in the ST165, only the 4.2 was.
 

wound3S

New member
Right, but there are multiple MR2 owners who have swapped this final drive into their MR2s (with the alltrac part number).

I can't remember if it's ATS or MCS motorsports that installs new OEM ST165 final drives with their rebuilt transmissions.

Plus having owned both MR2T and ST165, I can vouch that fifth gear is much longer in the celica -- though the actual fifth gear ratio is the same and the tire is less than 1% difference in diameters.

If I have the choice between believing my tachometer as well as dozens of MR2 owners or Hyper Rev, it's not a hard choice.
 

RedCelicaTRD

Moderator
wound3S":u68pv76d said:
If I have the choice between believing my tachometer as well as dozens of MR2 owners or Hyper Rev, it's not a hard choice.

Or you could look it up in the Toyota parts catalog. Notice the st165 part numbers are not the same as the 3.9 final drive part numbers you posted. Unfortunitly the same bad info has been pasted around quite a bit.

st165 Shaft, Output_______ 33321-20110
st165 Gear, Ring_________41221-20240
st165 Gear, Oil Pump____ 33407-20011

And as for the reason why your MR2 and Celica has such different cruise speeds, I couldn't tell ya. I know your car has had some work done to it and it is always possible you somehow got a RC/EDM tranny in there with the 3.9 final.
 

wound3S

New member
Wow, well I am gonna have to eat my words guys.

I had double checked the part numbers on toyodiy.com, but didn't notice that it directly my query with my earlier quoted number to the ST165 final drive which has a different part number.

I did some searching and found that the RC/CS ring gear has the same part number as US-market five-speed V6 Camry/Solara models. That is why many MR2 owners have been able to order the part directly from the dealership.

Additionally, it would appear that the "JDM" motor that the PO installed in the car that I bought was actually from europe. Good to know. Thanks for setting me straight :)
 

RedCelicaTRD

Moderator
wound3S":2me258ip said:
Good to know. Thanks for setting me straight :)

Everyone can make mistakes when you hear the same bad info over and over again. Now you can help get the MR2 guys on track :wink:
 

furiousgeorge

New member
its kinda funny to see the guy I got my celica from in the thread im looking at to swap a new tranny into said celica :p

Anyways, great thread, and I have a line on a st185 tranny that doesn't have any issues, so thanks for the info!
 
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