Can someone measure a t-case please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Scrub · 12-01-2003, 12:26 AM

Jose came by a few days ago to pick up a t-case. Only problem was the darn thing wasn't drilled out for the big bolts on the side mount. Anyone know why? anyway, I decided to use the case myself and I am drilling and tapping the holes, but I need to know how deep I can make them without blowing into the case.

Could someone measure the depth of the two side mount holes on a 205 t-case for a 72 k 20. Your will have to have a 205 laying around to do this.

I also need to know the size of the bolt. I think it is a 9/16 bolt.

Thanks in advance

jose · 12-01-2003, 12:45 AM

I am still stumped as to why those holes aren't there . I bet you that is the reason the bell housing is cracked on both sides . Maybe some one here knows what it came out of originally ?

Scrub · 12-01-2003, 12:50 AM

Did you figure out who was trying to break into your house?

jose · 12-01-2003, 12:57 AM

Neighbors gave me a general discription of the guy and i am keeping an eye out for him thru my scope .

72 CustomCamper · 12-01-2003, 02:33 AM

The only time I've seen those holes used is on a divorced case set up...

Chuck

Scrub · 12-01-2003, 10:32 AM

Hmm..
The frame on my project truck has brackets that are rubber mounted and would go into these holes. My parts truck also had the brackets, but the tcase was not drilled. I started looking at pictures on the web and found a case out of a t400 that wasn't drilled either. I want to drill mine as shown in this pic, Which is also a t-400 case.

I don't get it. If you don't use those holes, what keep the tcase from rotating?

Edit: crap, the pic didn't take

Scrub · 12-01-2003, 10:34 AM

Try this pic again

714x4 · 12-01-2003, 11:06 AM

Scrub, I just removed my transfer case this weekend. I'll measure the depth of those holes for you this afternoon when I get home from work.

JimKshortstep4x4 · 12-01-2003, 09:50 PM

Using a 3/8" diameter pin in lieu of a depth gauge, I came up with a hole depth of 1 5/8" in the transfer case that I have, (71 NP 205)

Incidently, all of our 4x4's with the NP 205 have the side brace
mounting. It is my understanding that some of the later trucks (73 and up) eliminated the side brace.

Jim

cheyenne10 · 12-01-2003, 10:15 PM

Board member Pont drilled an undrilled case last year. Try to get him to tell you how he set it up.

Scrub · 12-01-2003, 10:25 PM

Thanks for the information. I kinda figured it was a year based change. The older trucks were just built stronger.

Time to go play dentist.

Pont · 12-02-2003, 12:49 AM

Hey Bob, you've got a good memory!

Scrub, when the Rockwell t-case went bad in my truck, I decided to put later model stuff in my truck, easier to get parts.

The 4 spd trans and 205 t-case I installed came out of a 78 Blazer and the t-case was NOT drilled for the torque mount coming off the passenger frame rail. Off hand, I don't recall the correct bolt size but I think 9/16" sounds right to me. As for drilling depth, I drilled mine 1 1/2" deep (which is not deep enough) and used a flat washer and lock washer at the bolt head to take up the gap and firmly secure that bracket to the side of the t-case. Back when I did mine, someone on the board gave me a drill depth of 1 5/8" (I think) but I didn't want to take the chance of busting through the case. I'm sure there is plenty wall there on the case but I just felt better not drilling as far and taking up the slack with washers. A better alternative would be to drill it 1 1/2" deep and just run a 1/2" shorter bolt. Overall, mine truned out really good. No complaints at all. If you don't run the torque mount at all, I'm sure it will work but you might end up with a broken trans to t-case adapter like so many other people have. Drilling and taping is cheap insurance in my opinion.

Scrub · 12-02-2003, 01:10 AM

Thanks Pont.
The 1 1/2 is a really good Idea. mine wasn't surfaced so I got out a grinder and made it smooth. I then drilled the prescribed 1 5/8 inch hole and blew right through into the case. darn.
No big deal, the bolts that hold my corp14 cover on go into the case too. I will just put a little silicon on them. I quit after the pilot hole as I am going to change out all the inards and I will finish it when I have an empty case. Fact of the matter is I am going to blow both holes through so I can get a full depth thread tap without having to buy a 20 dollar 5/8 bottoming tap. Having to buy a new 17/64 drill bit is bad enough.

I think maybe the ones that are drilled might have a little deeper casting in that area, so let this be a lesson to all of us.

Thanks to all

12-01-2003, 12:26 AM	#1
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Can someone measure a t-case please Jose came by a few days ago to pick up a t-case. Only problem was the darn thing wasn't drilled out for the big bolts on the side mount. Anyone know why? anyway, I decided to use the case myself and I am drilling and tapping the holes, but I need to know how deep I can make them without blowing into the case. Could someone measure the depth of the two side mount holes on a 205 t-case for a 72 k 20. Your will have to have a 205 laying around to do this. I also need to know the size of the bolt. I think it is a 9/16 bolt. Thanks in advance __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-01-2003, 12:45 AM	#2
jose Registered User Join Date: Feb 2001 Location: Salem , Oregon 97301 Posts: 1,796	I am still stumped as to why those holes aren't there . I bet you that is the reason the bell housing is cracked on both sides . Maybe some one here knows what it came out of originally ? __________________ 68 GMC 4x4 SWB jose6772@yahoo.com

12-01-2003, 12:50 AM	#3
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Did you figure out who was trying to break into your house? __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-01-2003, 12:57 AM	#4
jose Registered User Join Date: Feb 2001 Location: Salem , Oregon 97301 Posts: 1,796	Neighbors gave me a general discription of the guy and i am keeping an eye out for him thru my scope . __________________ 68 GMC 4x4 SWB jose6772@yahoo.com

12-01-2003, 02:33 AM	#5
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	The only time I've seen those holes used is on a divorced case set up... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

12-01-2003, 10:32 AM	#6
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Hmm.. The frame on my project truck has brackets that are rubber mounted and would go into these holes. My parts truck also had the brackets, but the tcase was not drilled. I started looking at pictures on the web and found a case out of a t400 that wasn't drilled either. I want to drill mine as shown in this pic, Which is also a t-400 case. I don't get it. If you don't use those holes, what keep the tcase from rotating? Edit: crap, the pic didn't take __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends. Last edited by Scrub; 12-01-2003 at 10:37 AM.

12-01-2003, 10:34 AM	#7
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Try this pic again Attached Images __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-01-2003, 11:06 AM	#8
714x4 Registered User Join Date: Dec 2002 Location: Tempe, AZ Posts: 13	Scrub, I just removed my transfer case this weekend. I'll measure the depth of those holes for you this afternoon when I get home from work.

12-01-2003, 09:50 PM	#9
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Using a 3/8" diameter pin in lieu of a depth gauge, I came up with a hole depth of 1 5/8" in the transfer case that I have, (71 NP 205) Incidently, all of our 4x4's with the NP 205 have the side brace mounting. It is my understanding that some of the later trucks (73 and up) eliminated the side brace. Jim

12-01-2003, 10:15 PM	#10
cheyenne10 Senior Member Join Date: Apr 2000 Location: Oregon Posts: 2,512	drilling for mount Board member Pont drilled an undrilled case last year. Try to get him to tell you how he set it up. __________________ Bob

12-01-2003, 10:25 PM	#11
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Thanks for the information. I kinda figured it was a year based change. The older trucks were just built stronger. Time to go play dentist. __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-02-2003, 12:49 AM	#12
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Hey Bob, you've got a good memory! Scrub, when the Rockwell t-case went bad in my truck, I decided to put later model stuff in my truck, easier to get parts. The 4 spd trans and 205 t-case I installed came out of a 78 Blazer and the t-case was NOT drilled for the torque mount coming off the passenger frame rail. Off hand, I don't recall the correct bolt size but I think 9/16" sounds right to me. As for drilling depth, I drilled mine 1 1/2" deep (which is not deep enough) and used a flat washer and lock washer at the bolt head to take up the gap and firmly secure that bracket to the side of the t-case. Back when I did mine, someone on the board gave me a drill depth of 1 5/8" (I think) but I didn't want to take the chance of busting through the case. I'm sure there is plenty wall there on the case but I just felt better not drilling as far and taking up the slack with washers. A better alternative would be to drill it 1 1/2" deep and just run a 1/2" shorter bolt. Overall, mine truned out really good. No complaints at all. If you don't run the torque mount at all, I'm sure it will work but you might end up with a broken trans to t-case adapter like so many other people have. Drilling and taping is cheap insurance in my opinion. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

12-02-2003, 01:10 AM	#13
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Thanks Pont. The 1 1/2 is a really good Idea. mine wasn't surfaced so I got out a grinder and made it smooth. I then drilled the prescribed 1 5/8 inch hole and blew right through into the case. darn. No big deal, the bolts that hold my corp14 cover on go into the case too. I will just put a little silicon on them. I quit after the pilot hole as I am going to change out all the inards and I will finish it when I have an empty case. Fact of the matter is I am going to blow both holes through so I can get a full depth thread tap without having to buy a 20 dollar 5/8 bottoming tap. Having to buy a new 17/64 drill bit is bad enough. I think maybe the ones that are drilled might have a little deeper casting in that area, so let this be a lesson to all of us. Thanks to all __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

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