v6 conversion tranny question

[Stratman101]

Recently purchase a V6 converted S5. Did not know much about the motor or tranny. I have confirmed a Ford cologne 2.8 V6. The tranny is a 5 speed but unsure what it is. The gearing seems high? Low? Not sure on correct terminology 1st gear does not do much but make noise in fact better to start in 2nd. In 5th gear my speedo says 60 mpg at 3k rpm. Not that great for freeway driving.
Would i need a different rear end ratio to get me at 70 mph at 3k rpm?? Or?? If a stock rear end (which i cant confirm) would it behave like i describe? Thx in advance !

 

[260Alpine]

Probably T5 with lower first gear. Maybe you have the 4.22 rear? There is a tag on the transmission to ID. Picture of rear axle to see if it is stock?

 

[Stratman101]

Thx. Is there a better rear end if i have a t5 with that lower 1st gear? If it is 4.22

 

[Stratman101]

Pic of my rear end. Can anyone tell me if its stock?

 

[260Alpine]

Looks stock. There is a 3.89 for the stock rear. You can swap to a 72-75 Jeep CJ or Postal rear. They were usually 3.73, some were 3.08.

 

[Series6]

My question would be which T5 do you have? You need to match the trans to the axle ratio. I have a formula that can calculate if you enter the engine rpm, trans ratio, tire revs per mile, and axle ratio to project speed. PM me and I’ll send you the spreadsheet

I had a similar problem when I switched mine from a 4 speed non overdrive to a T5 with the .68. Rear axle is a Dana 44 with a ratio of 3.31. Fell flat on its face going into 5th. Changed the trans to a .80 overdrive T5 and raised the rpm in 5th by 400 rpm. First is low but I don’t worry.

 

[Series6]

Or you can stay with that trans and swap in an appropriate axle set.

 

[Slainte]

I used a Tremec T5, and switched the 3.89 to a 4.22. This brought back first gear, and I haven't noticed any loss at top end. Current speeds at 3k: 14; 23; 33; 44; 70, checked with a GPS speedo. Before this configuration, I had a worn T5 from an '84 turbo Tbird, and the stock SV rear end. First gear was a waste of time.

 

[Chad]

This chart is super handy for identifying T5’s and their ratios:
http://www.britishv8.org/articles/borg-warner-t5-id-tags.htm

It’s pretty easy to swap internals from one to another, if you found a used one with better ratios for instance. It’s been awhile, but you probably need to identify and respect the divide between World Class and Non-. But your current tailpiece, shift linkage, and I think the main case can be retained, if you find a used donor to harvest. Plenty o videos on utube, too.

 

[Bill Blue]

Not so sure you have a T5. Sounds very much like a TK5, which were used in Rangers up til about 1989. Fine tranny, but carries a 3.96:1 first gear! 5th is about .80:1, which works out fine with a 3.89 rear, giving about 70 @ 3000 rpm.
Bill

 

[bulldurham]

I have a t5 from a 3.8 v6 { 1993-4 }
It is a 1352-238 w/ following ratios:
Rev-- 3.15
1st--- 3.55
2nd--1.93
3rd--1.29
4th--1.00
5th--.72
1st gear is real short but maybe a little better than starting in 2nd.

 

[Stratman101]

Not so sure you have a T5. Sounds very much like a TK5, which were used in Rangers up til about 1989. Fine tranny, but carries a 3.96:1 first gear! 5th is about .80:1, which works out fine with a 3.89 rear, giving about 70 @ 3000 rpm.
Bill

Hmm. So i have a later S5 vin 12o51. I understand my gearing s/b 3.89 not 4.11 due to my vin being after 10000??
I jacked up the car and marked the flange, rotated left wheel 2 revolutions and i get just under 2 turns on the flange. Does that confirm a 2.89??

 

[Stratman101]

Looks stock. There is a 3.89 for the stock rear. You can swap to a 72-75 Jeep CJ or Postal rear. They were usually 3.73, some were 3.08.

I found a 78 cj5 with 355 gearing. How might that work you think??

 

[Stratman101]

Hmm. So i have a later S5 vin 12o51. I understand my gearing s/b 3.89 not 4.11 due to my vin being after 10000??
I jacked up the car and marked the flange, rotated left wheel 2 revolutions and i get just under 2 turns on the flange. Does that confirm a 3.89?

 

[260Alpine]

Would have to be narrowed. If you have an 8" Ford you can easily change the center section to change ratio. If you can find one. Late 70's Ford Granada and Mercury Monarch.

 

[DanR]

I found a 78 cj5 with 355 gearing. How might that work you think??

Mustang II, Mercury Capris/Bob Cats and Pintos have a 3:55 to 1 ratio that will be a good choice (just have to shorten) like most others.

 

[Bill Blue]

Hmm. So i have a later S5 vin 12o51. I understand my gearing s/b 3.89 not 4.11 due to my vin being after 10000??
I jacked up the car and marked the flange, rotated left wheel 2 revolutions and i get just under 2 turns on the flange. Does that confirm a 2.89??

For some reason, guys on the internet insist on claiming that 3.80 rear gears were placed in all late Series V cars. I consider that to be a great myth, at least for US cars as I've owned two of them, both with 4.22.
Bill

 

[Stratman101]

My transmission has no tag. The only marking i see is s snowflake with “87” stamped on it.

 

[husky drvr]

I knew USA/Canada had a production difference for rear axle ratio but couldn't find the break points listed anywhere.

This is what the parts listing gives for those points.

Any unit not destined for USA/Canada used 3.89:1 unless equipped with O/D

USA/Canada standard trans non O/D up to B94102640 used 3.89:1

USA/Canada standard trans non O/D from B94102641 until B395010312 used 4.22:1 (early Feb. '65 until mid Sept. '66 production.)

USA/Canada standard trans non O/D from B395010313 returned to 3.89:1

 

[Stratman101]

Interesting. My vin reads 12051.
Safe to assume i have a 4.22?