Changing 5th gear ratios on Ford t5

Started by tbo, September 25, 2018, 01:38:48 PM

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tbo

Hello Guys . Need your help.Ive got an 84 Mustang/Capri non WC  with a 295 first gear and a .63 fifth gear. The top gear is way to long and I want to change it to a .80 fifth gear. Looking on Ebay there is a gear set available to do this It has a 5th counter gear with32 teeth and a 5th gear main shaft gear with 20 teeth with 28 splines which  when installed  will give me a..80 final drive .It also says for WC only .How do I verify that I will end up with a.80  ratio and will it fit on a non WC main shaft. this kit is from Competition  Transmissions

mgb260

Tim, If they say WC only it won't work. You need the set that was .73. It was also available in the 83/84 Mustang V8 T5 with 2.95 first. It was also available in the Camaro/Firebird V8 with the 2.95 first. To use the GM OD gears you would have to switch main shaft and slip yoke.I told Carl the tooth count for the two gears awhile back. Don't have those notes here. EDIT: found the tooth count for NWC .73 OD gears: 31 drive and 55 driven.

tbo

Hi Jim. Thanks for responding. First of all I must say I have the T5 trans in my TR2 now and it works fine except when I change from fourth at 3000 rpm to fifth it drops to 2000 rpms and makes the 2.2 litre 4 sluggish to get more revs. It has a custom driveshaft for the Ford T5 so I don;t want to change that.Is it possible to change the main shaft to a WC one along with the two fifth gears?I'm worried that  the NWC .73 gears may also be too tall also and the .80 ratio would put me at 2400 rpms in fifth with enough torque to rev better up to 65 or 70 miles an hour cruising speed.Thanks Tim

mgb260

Tim, I don't know if the WC main shaft will swap. Call Modern Driveline and ask. What rear ratio do you have? You could go lower (higher numerically) or to a lower diameter tire. Or build your motor for more power.

IaTR6

Tim, Two places to look for information are: Pro-ForcePerformance.com for the history of the T5, and 5speeds.com
for videos explaining details of the T5.
From what I find, the 2.95 first gear unit has options of 31T/55T for a .72 o.d., and 33T/53T for a .80 o.d. I have not found
the 33T/53T set, and one place lists them  as no longer available.
Changing the two gears is a little involved, the counter gear comes off with removal of a snap ring, but the mainshaft gear usually requires a press.
The mainshaft has to be removed in order to press the gear off and the new one on, which leads to "well, I might as well" regarding synchro, bearings and
seals. Pretty soon you are talking replacement cost. I desperately wanted to change my 3.35 first trans to 2.95, and that requires the counter gear, and
the three forward gears plus the two overdrive gears. So, I fixed the oil leak, replaced the input shaft seal and decided to cuss it when the first gear seems
too low. (I have a V8)
You will see that the o.d. gear choices result in a different overdrive ratio when using the 3.35 gears as the input/counter tooth count is different. If I had changes to a 2.95 input/counter gears with the associated forward gears, my overdrive would have been .59, which is really tall.
Dennis

tbo

Hi Jim. I suspect the main shafts are not interchangeable since the 93 WC trans has bearings and  the 84 NWC doesn't. I will call Modern Driveline. The rear ratio  on TR's is 3.7  No options there and then it changes all the trans gear ratios if you go to smaller tires. Hi Dennis Thanks for helping out. . I guess the only way to go is to find a93 T5 with the 295 first gear  and then tear it down and install  the .80 kit . Put it in the car and sell the 83 NWC to recoup some costs . Still wondering if the .73 gear set would be too tall ? Would maybe be ok in TR6 with more torque available with 2,5 litre. And I thought this would be easy because of all the gear ratios available . Thanks again guys  Almost forgot tosay in the ID tag listings of T5's there is a mystery Ford Wc trans number  1352 225 which has a 292 first gear and a .80 fifth gear which is the very trans I need. but it has no listing of what car it was in. How would one find out the answer to that ? The plot thickens

mgb260

It is probably aftermarket, Ford Racing,Tremec etc. Besides the 83/84 NWC I think all other Ford T5's had the 3.35 first.  Datsun/Nissan also used the T5 in some 280ZX and 300Z cars. I believe it was Ford pattern with different input shaft/splines. 81-83 had 3.5 first. 84-86 had 3.35 first.

MGBV8

"The rear ratio on TR's is 3.7 No options there..."

The confusing thing about saying TR is that there are so many different models of TR.

We have two different rearend ratios for our TR6 race car.
Carl

rficalora

RE: TR gears...

Richard Good-something-or-other (forgot his last name) sells bits to swap to a Nissan R200S differential.  A few gear choices there including 3.54 and 3.31.

MGBV8

Carl

tbo

Hi Carl.I always thought Triumphs TR2  to TR6 ran a 3.7 gear. What ratios are you running in your race car?Changing the rear end changes all the gears in the trans and I like all of them now very nicely except for the too tall .63 fifth so I'm sticking with that . I'll run it as a four speed untill I can build up a WC  trans with the .80 over drive.Am I correct in calculating that when I shift  at 3000 rpm in fourth that I will end up at 2400 rpm in fifth?That is what I have to know.

MGBV8

We have a 3.45 in the TR6 race car.

I have been using a T-5 with a .63 5th gear for 17.5 years.  Works great with the MGB stock 3.9 rearend.  ;)
Carl

tbo

Hi Carl .That's interesting.I had a friend of mine drive my TR2 yesterday and after three or four miles he said he thought the tachometer was reading high . At 3000 in 4th gear he thought it did not feel like 60 miles per hour.Ive been thinking all day what if I'm shifting at 3000 and dropping to 2000 in fifth and really i'm at1600 or 1800 in fifth. No wonder the car is lugging. I am going to have to get a precise measurement of my rpms with another independant tach. Will keep you informed

MGBV8

I believe that the USA carb version of the TR6 was 3.7 & that the EFI UK version was 3.45.   I don't think the 3.45 was ever offered as OEM in the USA.
Carl

waterbucket

The genuine 0.8 gearset is no longer available from Tremec, any that come on the market make very high prices. The 0.8 ratios that are currently for sale are after market ones with larger teeth, this has the advantage of being stronger but the disadvantage of being noisier and the need to grind a small amount from the tailhousing to give clearance for the slightly larger gears. The original 0.8 was fitted to the Sierra Cosworth and some TVR's but was a little weak and often broke up when being removed from the shaft. This is of course no help in telling if they will fit a NWC T5

tbo

Hello Phillip. That is kind of nice to know. I'm going to get my tachometer problem sorted out and then see if i can use the.73 ratio gears in the 83 NWC trans so I don't have to buy another trans etc.

waterbucket

Hello Tim
I found the info that I was looking for here  http://www.5speeds.com/t5/s80.html It shows exactly where you need to remove some metal. It also states that in a GM T5 you need to fit the Ford tailshaft and change the driveshaft yoke as well.
As you can see this gearset is not cheap.

5speeds.com state near the top of the page "Other companies have manufactured gearsets based on this very design". I did see on the USA Ebay several vendors selling a similar (same?) set for about $120
 I would be interested to know if these "cheap" 0.8 gearsets are of a similar quality to the 5speeds.com ones.
Let us know how you get on.
Philip

tbo

Thanks Phillip. I will check out the info  and keep you informed. Getting tach accuracy done first.

tbo

Got the tach checked out by hooking up a MGB electric tach and running the motor. At 2000 rpm on the electric one the TR2 tach read 1900. At 3000 electric the TR2 read 2900 so that was that.Took the car out yesterday and shifted into 5th at higher speeds At 3500 rpms  in 4th the rpms in 5th were 2500 and not enough power to run it Pretty much same at 4000 in 4th .down to 3000  in 5th and some acceleration in 5th  Since  I want to use 5th at between 60 and 70 mph  the .63 ratio is useless at any speed.Will have to figure out mathematically what the .73 ratio will do for me. Any info on that available? Tim

MGBV8

Quote.Will have to figure out mathematically what the .73 ratio will do for me. Any info on that available?

Sure.

http://forum.britishv8.org/read.php?10,63500
Carl

IaTR6

Tim, If you are at 3500 rpm, and using .63 overdrive, you should read 2205 rpm in 5th. At 4000 in 4th, a .63 5th would give 2520 rpm.
A 3500 to 2500 change is .71, and 4000 to 3000 is .75. Is it possible you have a .73 now, since that would fall within the error of the tach reading?
When I look at my listing of T5's, the .63 5th ratio seems fairly rare. It would mean taking the tail housing off, but for a 2.95 first gear, the overdrive gears should be 25/51T. I assume the aluminum tag with the 1352-11-___ is missing? Is there a partial VIN on the right side of the case on the mounting flange? (outside
surface, not on the bell housing face)
If so, it may be possible to identify the transmission. Case casting numbers are less reliable, but may help also.
Dennis

tbo

Finally saw how to access the Speed /RPM calculator and got some interesting info.In 4th at 3000 rpm /60mph with the .63 5th gear the revs drop to 1849 a difference of 1085 rpm. With the.73 5th gear the rpm drops to 2142 a difference of 792. With a .80 5th gear the rpm drops to 2318 a difference of 606 rpm . Available Horsepower between 2000 and 4000 is(don't laugh) 85 to 90 . So can I switch to the .73 gears and not have to find a WC trans  which will accept the .80 gear set or just plat it safe and go there any way. Of course I have to find a WC trans in good shape with the 295  .63  configuration and then the .80 gear kit . All of that is fraught with problems too.I need a gambler from Vegas to tell me the odds.!! Thanks for the graph Carl

tbo

Hi Dennis. As you can see I did all of my calculations at 3000 or 60 mph.  As to the trans ,the chap I bought it from had it in a 68 Mustang . He is an engineer BTW and was putting a big block in the car and another trans. He said the trans was out of an 83 Capri which means it sould be 1352-065 Of course  the tag was missing  so I had to take his word I think we checked the 5th gear by manually rotating the input shaft and it checked out but .63 or.73 who knowsI think fo now I'm putting the car away and working on a TR3 that taking up all the  room in my heated garage.Maybe i'll get lucky and find the correct WC trans over the winter.If any body has any ideas please send me a PM  Thanks Tim

ex-tyke

Quotewe checked the 5th gear by manually rotating the input shaft and it checked out but .63 or.73 who knows...
If done carefully, you should be able to distinguish between a 0.63 and a 0.73 fifth gear.
I have a spare Ford T5 in the garage with a 3.35 first and 0.68 O/D - all gear ratios identifiable using the input/output turn test.

tbo

Hello Graham . Nice to hear from somebody local. When I bought the trans about 3 years ago  I knew very little about T5s .63  .73  what does that matter. Do you know of anyone with a spare t5 from an 85 mustang? that would be 1352-126 WC with a 335 first and a .80 5th Just the one I need! I think I'll post an ad on Kijiji and see what happens. If you seek you might find .As far as the trans being .63 or .73  I can find out when I pull it . I know for sure it's too tall Tim