Hi,

I am a new user here and I hope I'm not creating a redundant topic. I bought a 2001 Magna TJ wagon with Automatic Transmission, less than 3 months ago, I already spent a couple of grands to fix some problems it had (new timing belt, service belts, new engine gasket, new spark plugs etc) and all was OK and the car was driving a charm, but unfortunately the other day while reading on the freeway I suddenly lost ALL my gears. My mechanic said it's a common thing for Magna TJ's and I will need to replace it. To recondition it is out of question (quote is 3 grands plus labor to fit it in) so I'm looking for a second hand transmission.

Now, my question is as follows:
can I use a transmission with a slightly different ID number? I found for $350 a 2nd hand one but the ID numbers are F4A51 K2E5B while the one on my car is F4A51 K2B5B. The whole difference is that E instead of a B. I know this transmission comes from a Magna TJ too (at least, this is what the guy who's selling it said) and I know that the letter means the "Final Drive Ratio" of the transmission, where B indicates a ratio of 3.274 and the E indicates a ratio of 3.735. (see page from a manual I found http://oi44.tinypic.com/2m3pd2t.jpg).

Are the two transmission compatible or should I find a transmission with the exact same ID number?

Thanks for your help.

In short you can use ANY 4sp auto from TF to TJ with no issue at all. Dont get too wound up with the trans numbers provided the trans comes out of one of the models ie TF, TH, TJ or KF, KH series 1 KJ

The 3.735:1 final drive ratio suggests that box is from a 3l (6G72) car, whereas yours with the 3.274:1 ratio is from a 3.5l. Notwithstanding the mechanical & electrical compatibility noted by Madmagna, installing the 3l box may result in the engine running at slightly higher revs for a given speed (by about 7% if my calculations for 4th gear are correct).

If the seller has the ECU to go with that gearbox (which you wouldn't need for your purposes), I'd be interested in more details.

HI my transmission in my tj 2 years ago broke down and took it too nova transmission specialists and reconditioned it for $1500 and replaced the spring for a more heavy duty one,the transmission is still good as new.

thanks guys for the answers. So I can buy that gearbox easy and put it in, that's good news.

How higher revs will affect the drive practically?
what would you do in my place? use this gearbox (easier and cheaper to find) or look for the same one?

The revs running the 3l box in 4th gear would be much the same (very slightly higher) than the revs that a car with the 5 speed auto would run in 5th, so it isn't an outlandish change.

It is likely to slightly improve response in lower gears, particularly given the shift maps in the 4 speeds.

However I would suggest many people would not notice much difference. I only mentioned it so you wouldn't be surprised if you went ahead and then did notice the difference in revs... ;)

There may also be a difference in response due to the different torque converter, but I can't really tell you much about that as I've not driven a car so fitted.

Practically, IMO if you need the wheels a working gearbox at hand is worth more than a theoretically better one...

yeah! I fitted it and is working great!!
thanks a lot you were extremely helpful