Transmission / Overdrive: T 10 Trans info needed

[Mark Plucenik]

Hoping someone can help with identifying my 4 speed so I can order the correct parts for a rebuild. I'm confused with the wide ratio vs close ratio subject. Reading on the forum, close ratio 1 st gear should be 2.20 and wide ratio 1 st gear should be 2.54. My cluster 1st gear count is 17 and 1st gear is 36. that work out to about 2.12 (close ratio?) The numbers on the case T-10-1B Q1 K.18.61 assuming this is a 61 gearbox? the input shaft is 10 spline & the output shaft is 16 spline. The total cluster gear counts are 17-20-23-and30. Before I put allot of effort into this I would like to know if its correct for my car. The rest of the driveline is a 289 and a 3:54 TT rear.
Thanks for any help, Mark
I believe this is the chevy bolt pattern. Looks like 1 ring on the input shaft But I have only 10 input shaft spline count unless I"m counting wrong. Just counting the high spots not the grooves or slots. My clutch disc fits.

[64studeavanti]

Check the input shaft for rings (grooves) the 2.20 close ratio has no rings. The 2.54 has one. Additionally, the number of teeth on the input shaft is 25 for the 2.54 and 27 for the 2.20.
does the trans have the Chevy or Ford bolt pattern?

I

[64studeavanti]

FWIW, the cluster gear identifies this as a wide ratio 2.54 first gear trans.

[64studeavanti]

I have this combo, 2.54 first gear and 3.54 R/A, in my 64 Avanti. Works pretty good. The only complaint is that 2nd is pretty close to 1st. Often, I will skip 2nd and go from 1st to 3rd.

[irish]

64studeavanti is correct. If you have a groove in the input shaft it's a 2.54 to 1 first gear. Sometimes the groove is faint, like the one in the picture below.
What is this transmission from? I've rebuilt, bought and sold alot of T-10's over the years if you need any help let me know.

Regards,
Joe

[irish]

Thanks for adding the pics. You have a 2.54 to 1 first gear start chevy bolt pattern T-10. Date code states it was built on Wed. Oct. 18th, 1961 during the first shift. It would have been originally installed in a 1962 GT Hawk. The gears don't look too bad, looks typical of most. Usually the problem will be with the brass synchronizers, with a hard shift into 2nd gear as the first tell-tale sign of problems. These are easy to rebuild for an experienced transmission guy. Just be aware of the type of gear oil you use or you can ruin the brass synchronizers. Also, a 10 spline input shaft was used on all the Studebaker T-10's.

Regards,
Joe

[Mark Plucenik]

Thank you all for the lightning fast response. All the gears look great to me. There was some light metal flake in the sludge in the bottom , thinking normal ware. This is going to be a spare for my car, I just did not want to waist time & money on the wrong unit. So this would be classified as the wide ratio, right? If it were a drag strip car it would be better off the line? As for the gear oil I plan on using Amsoil full synthetic 90 wt. Maybe add a tube of BG .

[StudeRich]

Add a Tube of BG, WHAT?

It is not a Limited Slip Differential, it doesn't NEED Anything added.
Many Stude. people including Racers prefer the Red Line Synthetic MT-90 Gear Oil for a smoother, faster Shift.

https://www.redlineoil.com/mt-90-75w90-gl-4-gear-oil

[64studeavanti]

Check the front bearing retainer. It should say T85C-6D for Studebaker.

[64studeavanti]

I second the redline mt90.

[Mark Plucenik]

I will get the Redline 90 , thanks, also , talking about the shifting. The factory shifter is OK at best. I have not really tried adjusting it but the through between gears is too long for me. do you guys have any recommendations for a better quality shifter , maybe a Hurst? Something that would bolt up and fit a GT Hawk without doing any cutting in the floor.
And just to confirm, this would be the wide ratio trans? Mark

[64studeavanti]

Yes, wide ratio trans.

[64studeavanti]

Most racers would want the close ratio to keep the rpm up between shifts. They would also use a lower (numerically higher) rear axle such as 4.09 or 4.55 etc, depending on engine, for a quick launch.

[64studeavanti]

I have a Hurst shifter for the 64 Avanti. Lots of mods to make it work. I do not believe a bolt in is readily available unless you can find good used.

[stude1964]

Mark
If you want your '64 to be correct the trans you pictured is incorrect. The shot of the case shows it's the wide pattern trans for a '61/2 V-8 application. The trans you want for your '64 GT has a pattern which is more square and uses the regular V-8 bellhousing for any stick or OD trans.
Rob in PA.