T5 experts come in

[Black1987Stang]

Is it possible to change just the 5th gears from one t-5 into another...I had a t-5 with the 2.95 1st gear, hardened countershaft, and the .059 5th gear overdrive which is VERY low as in at 2200rpms I was doing 80mph.......Well I blew 5 teeth off the 3rd gear part of the countershaft out of that trans...I got a bone stock t-5 from my friend which is in my car now and the 5th gear SUCKS in it...Im at 3,000rpms at about 75mph...Im driving a 14 hour drive soon so I was planning on taking the 2 5th gear gears out of that trans (which i already have out) and swap it into the trans in my car now, do u guys see anything wrong with that? only thing that holds them on is the 2 clips, I just want to know if theres any special things I dont know about before I take the trans out of my trans now and swap the gears out. Thanks

 

[795.0pacecar]

Im pretty sure what your planning will work just fine.

 

[Mustang5L5]

Yes, it is possible to do that.

However keep in mind the 5th gear ratio is also determined by the ratio between the input shaft and countergears. I am not sure these are the same on the 2.95 gearset vs the 3.35 gearset. It is entirely possible the two use the same gears but the ratio is different due to a different input/counter ratio.

The 3.35 5.0 and 4-banger T-5 use the exact same 5th gear gears, but the ratios are different due to the input and countergears havving different ratios.

 

[Black1987Stang]

Yes, it is possible to do that.

However keep in mind the 5th gear ratio is also determined by the ratio between the input shaft and countergears. I am not sure these are the same on the 2.95 gearset vs the 3.35 gearset. It is entirely possible the two use the same gears but the ratio is different due to a different input/counter ratio.

The 3.35 5.0 and 4-banger T-5 use the exact same 5th gear gears, but the ratios are different due to the input and countergears havving different ratios.

I hear what ur saying, the guy before me redid that trans with the 2.95 gear countershaft and different aftermarket 5th gears...I meant to say its an aftermarket 5th gear setup not like a trans from a different year or something, since both trans have the same tag number (5th gears also the same color as the new counter shaft, black coating, whereas everything else is grey or w/e which is all stock parts)...I just counted the teeth on the aftermarket 5th gears...small gear is 27 and bigger one is 59...I think that comes to a .45 ratio right? if u go on astro performace or place like that they sell .59 and .63 overdrive...which is prob mine but they figured into the ratio of the counter and input gear also, have no idea tho...either way im planning on putting this setup in the my trans in my stang now

 

[Mustang5L5]

just counted the teeth on the aftermarket 5th gears...small gear is 27 and bigger one is 59...I think that comes to a .45 ratio right?

Unfortunately i just counted the teeth on a STOCK (for a 3.35 gearset) 5th gear.

Small gear - 27 teeth
Large gear - 59 teeth

same tooth count as your 5th. I did some research and there are 4 different factory 5th gearsets. Depending on which gearset you use (2.95 or 3.35), you will get 8 different 5th gear ratios.

Your gears when used with your 2.95 set did give you a 0.59 ratio, but they give you a 0.68 ratio when used with a 3.35 gearset. This is due to the input shaft and countergear tooth counts being different.

2.95 the 59/27 5th gearset

Input shaft - 24 teeth
countergear - 31 teeth
5th Large gear - 59 teeth
5th Small gear - 27 teeth

24/31 = 0.77
0.77 * 59 = 45.61
27/45.61 = 0.59 ratio

3.35 with the 59/27 gearset

Input shaft - 23 teeth
countergear - 34 teeth
5th Large gear - 59 teeth
5th Small gear - 27 teeth

23/34 = 0.67
0.67 * 59 = 39.91
27/39.91= 0.676 ratio


So anyway, to make a long story short, if you want a 0.59 5th gear ratio again, you are gonna need a 2.95 gearset transmission. 0.68 is the lowest you can go with the 3.35.

Hope all that math makes sense to you

 

[Black1987Stang]

ok I totally gotcha now .....just bare with me I have no clue about speed and ratios and all that. ok. right now I have a bone stock trans right now (last 3 numbers on tag is 169)....the 1st gear is about worthless as you know with the 3.35 gearset and my 5th gear right now is...at 3,000 rpm im doing about 75mph.....I can deal with the low 1st gear but I need to do something about the 5th gear I have to make a 14 hour drive pretty soon and I dont want to have the motor revving out and only be cruising at like 75mph. My car supposedly has 373s in it, I dont think they really are only because of how low my 5th gear is now (since now its a stock trans) and I hear people with 373s with stock 335 gearset at like 2700 rpm doing like 80 or so in their 5th gear, which is right around the area I want......but since they have 373s and Im supposed to have them too why is mine acting like I have 4.10s or steeper gears? Tomorrow Im going to try and find out what I truly have by a couple ways. btw im running 255-50-16s, 26 inch tires I believe it comes out too. Basically what im trying to figure out is what I should do to get a comfortable cruising speed in 5th gear like everybody else has except me only thing I can think of is changing the rear gears?, which im not sure to go to since mine seems so steep but is supposedly 373s....is it possible to actually get a different ratio 5th gears so I can swap them out and be done with it without messing with all my other gears? Any advice would be greatly appreciated

 

[Mustang5L5]

Your tire size is close to stock, so that's really not an issue.

The trans ID tag means it's a t-5 from an 85.5-89 Mustang, rated at 275 ft-lbs of torque. The stock 5th gear for that trans is 0.68. That's the lowest factory 5th gearset you can use.

Unsure if there are aftermarket gears to make it lower. I'll take a peek around and see what i can find