T-35 swap

[dowlenjj]

I have a 1965 ton 4 wheel drive truck. It is in awesome condition, and I use the truck frequently in my business. I want to swap out the 304 four speed with a 345 five speed t-35.I have the donor. I need some help with the transfer case shift lever possibly a bracket of some kind. The t35 does not have a place to bolt the lever on. Has anyone ever done the swap, and if so what was done with the lever.
Thanks, jeremy

 

[RobertC]

The t-35 is a med duty IH truck transmission. Most of these probably did not "offer" 4wd.

The t-34 and t-36 were the 5 speeds that were put in pickups and t/as.

I think there are 1 or 2 people (that do not "show up" daily) here that May have done this swap (or the t-34 / t-36).

 

[overdrivesteve]

Hi,
please excuse my ignorance, but I'm new to IH trucks. I just recently purchased my first IH, a 62 crew cab 3/4 ton with 304 v8 and 4 speed and divorced transfer case. I'm still waiting for it to arrive.

But I would like to seriously consider upgrading to a 5 or 6 speed trans. My question is, will the t35 be a direct swap for the 4 speed? (other than possibly shorten the shaft between the trans and transfer case). And how does it differ from the t34 and t36? Is there any place that lists the gear ratios of the different transmissions? Finally, how are these different from the nv4500? It seems like if t34-t36 transmissions will bolt directly in place of the 4 speed, what's the advantage of the nv4500 that needs an adapter plate? And do all transmissions mentioned in this post use syncroes?

Thank you for your help.

Steve

 

[FDChappie]

Short answer is no a different bell housing and clutch disk are used.

The t-34 is a close ratio 5-speed that is a nice trans, I have one in a '71 travelette. It's driven like a 4 speed with the granny low when needed. There is a u shaped shift from 1st to 2nd.

The t-35 is a wide ratio box that will work best with a 2 speed rear axle.

The t-36 is an od trans with u shaped shifts between 1st, 2nd and 3rd, 4th. 5th was toward the dash.

All three of these transmissions have been in various IH vehicles I've had in the past. They all have straight cut gears with syncros on 2nd - 4th that are noisy but strong.

The travelett is set up nice with 3.54 gears in the back and cruses 70+mph nice. The granny is low enough that it would make a descent stump puller.

 

[overdrivesteve]

So you're saying for me to upgrade to a 5 speed I also need to change the bell housing and clutch disk, correct? Then would a newer "5 speed" bell housing work in an old 62 crew cab, 3/4 ton truck without drilling, welding or fabricating new cross members or pulling the engine? Can a replacement bell housing be installed from under without pulling the engine? And when looking at a bell housing at a wrecking yard, how can I tell which IH 5 speed trans it was made for?
Sorry for all the questions -- I'm still learning.
Thanks.
Steve

 

[FDChappie]

Fortunately I've never had to pull one so I don't know. I'd imagine you'd want to get everything from the bell housing to the tail shaft. The bell housing is where the rear motor mounts are so there is no rear cross member per say.

 

[RobertC]

short answer is no a different bell housing and clutch disk are used.

The t-34 is a close ratio 5-speed that is a nice trans, I have one in a '71 travelette. It's driven like a 4 speed with the granny low when needed. There is a u shaped shift from 1st to 2nd.

The t-35 is a wide ratio box that will work best with a 2 speed rear axle.

The t-36 is an od trans with u shaped shifts between 1st, 2nd and 3rd, 4th. 5th was toward the dash.

All three of these transmissions have been in various IH vehicles I've had in the past. They all have straight cut gears with syncros on 2nd - 4th that are noisy but strong.

The travelett is set up nice with 3.54 gears in the back and cruses 70+mph nice. The granny is low enough that it would make a descent stump puller.

The above info on t34, t35 and t36 transmissions is incorrect.

T34 and t36 transmissions were available as an option on t/a and pickups (do not know the first year they were available) as well as other IH trucks.

As near as I can tell from postings the t35 transmission was only used in medium (and heavier?) duty trucks.

T35 and t36 transmissions are direct drive - 5th = 1.00

t34 transmission is an overdirve - 5th = 0.83

the gear ratios in the t35 (1st, 2nd, 3rd and 4th) are slightly lower than the t36... 1st gear t35 = 7.0 while the t36 (and t34) 1st gear is 6.2

transmissions are non-synchro 1st and reverse.

There is no such thing as wide ratio / close ratio in these boxes.

There is a "wide gap" between 3rd and 4th in the t34 which most people do not like for heavy duty work / heavy duty towing.

There should be other postings with a complete list of gear ratios. Edit 1 - decided to look them up - edit 2 - changed t34 / t36 values to those in a 1971 IH road test article

t-34 = 6.21, 3.43, 1.81, 1.00, 0.82

t-35 = 7.17, 3.96, 2.37, 1.41, 1.00

t-36 = 6.21, 3.43, 2.05, 1.22, 1.00

the 5 speeds have their own unique bell housing (and throwout bearing), so you need the IH 5 speed bell housing.

Might also need the cross member that supports the 5 speed transmission.

The 5 speed transmission is longer and from what I have "read" the cross member "sits back". You can check your frame for a set of holes "set back a little", but being a 62 they might not be there.

You can shorten the shaft between the transmission and divorced transfer case.

Obviously, the nv4500 is a modern transmission.

Which one to use is up to you.

 

[FDChappie]

I stand corrected the t-34 is indeed the od transmission.

 

[overdrivesteve]

Hi,

I have another question I'm not really clear on. I asked this elsewhere but probably better belongs here - can a bell housing for a 5 speed trans be properly installed in my truck with no fabrication modifications anywhere at all?

I know for the trans install I will need to cut a hole in the floor for the shifter and make a custom intermediate drive shaft.

And is my stock clutch master cylinder bore the proper size for the slave cylinder used with the 5 speed clutch? This is my present clutch m/c:
International pickup & Travelall parts.com

This is a 1 inch bore but as you can see, if I need some other clutch m/c bore size, it will require some major clutch pedal redesigning.

I'm still just trying to get the pros and cons of all the different trans swap possibilities before I make my move.

As a final question, does anyone know if the bell housing can be replaced on this truck without pulling the engine? I've never done a bell housing swap before, not even in a Chevy.

Thank you for your patience with all my questions. And sorry if I hijacked this thread.

Steve

 

[overdrivesteve]

Hi,

after a month of internet research, I would like to post my findings for anyone contemplating a 4 to 5 speed swap. Some of this info was stated above - I'm just re-summarizing my understandings. Let me know if you agree or can add any info, as that would be appreciated. I'm still very new to IH trucks and May have it all wrong anyway.
But basically there are 3 different series of IH 5 speeds, all summarized below with their corresponding gear ratios:

_ _ _t31_ ___ _t32_ ___ _t33 - no syncroes
_ _ _t34_ ___ _t35_ ___ _t36 - syncroes except 1st and reverse
_ _ _t434_ __ _t435_ __ _t436 - short-lived 2-year design
_ _ _t494_ __ _t495_ __ _t496 - began in 73 or 74
_ _ _t696_ __ _t698_ __ _t699 - early 80’s to early 90’s
1__ _6.21_ _ _ _7.17_ _ _ _6.21
2__ _3.43_ _ _ _3.96_ _ _ _3.43
3__ _1.81_ _ _ _2.37_ _ _ _2.05
4__ _1.00_ _ _ _1.41_ _ _ _1.22
5__ _0.82_ _ _ _1.00_ _ _ _1.00
r__ _6.09_ _ _ _7.02_ _ _ _6.09

shift pattern:
_ __ _t34_ _ __ _t35 and t36
___ _1-2-5_ _ _ _ _1-2-4
_ __ _-n-_ _ _ _ _ _-n-
___ _r-3-4_ _ _ _ _r-3-5

the newer transmissions usually came with a 1.5 in input shaft, however, 1.25 was available for them too.

The transmissions are externally all the same size, and with the same length of input shaft, so if one will fit under your floor pan, then any can fit. However, the parts will not interchange between the different series of transmissions.

The Scout never came from the factory with a 5 speed transmission.

IH never made a 5 speed that was married to a transfer case.

5-speed transmissions require a different transmission bell housing bolt pattern from the 4 speeds, however, there were some bell housings manufactured by IH that are drilled to accept either a 4 speed or a 5 speed transmission.

In changing bell housing types from one engine to another, the bell housing should be adjusted for less than .005 run-out and not just depend on the attaching bolts to properly locate the bell housing.
There was an excellent detailed discussion on this topic in another IH forum relating directly to IH truck bell housings, but unfortunately that forum crashed and I don't know if that info will ever again be republished on the internet. Here are three other non-IH but related links I gathered from that discussion:
lakewood bellhousing
http://www.hurst-drivelines.com/files/GM dial indicating - robbmc instructions revised 6-15-09a.pdf
robbmc performance products - bellhousing alignment dowels

If you have the hydraulic clutch system, that seems to be the preferred way to go as it mostly remained unchanged throughout their entire range and lifespan.

Flywheels are usually drilled for both 11 and 12 inch clutch or 12 and 13 inch clutch, are separately balanced from the engine, then balanced with the pressure plate, and are usually marked how the two go together. And any flywheel will bolt to any IH sv v8 engine. (sv stands for small v)

a couple different pressure plates are used by IH. But my past experience with trucks other than IH has taught me there is no design better than the borg n beck. When I have IH Parts America do my transmission swap, that is the pressure plate I will request.

As for the little parts, such as pilot bearing, throw out bearing, collar, etc, I have been unable to find any definitive information on the internet, other than there are 4 different collars used by IH over the years. But beyond that I'm not clear if they are still available from IH. I would guess it must not be any big deal to someone with an IH parts book, otherwise I'm sure more online info would be available for the swap's small parts.

One more final comment, the nv4500 5-speed can be successfully installed and with great reviews, using the adapter from IH Parts America, and that is the transmission I would use as its a newer, very well designed and supported transmission. However, it only comes in overdrive. That is why I'm now researching these other transmission possibilities, and for my application, I will eventually go with the t35 or newer series of IH transmissions.

Please add more to this post if you can, and let me know your experience with the different transmissions.

Hope this info might help someone.
Thanks.

Steve

 

[RobertC]

First and reverse are non-synchro.

The transmissions are large -- I "think" at least one person has put an IH 5 speed in a Scout II (other forums). It requires a body lift (or transmission tunnel modification) to clear.

The collar / to bearing (and pilot bushing?) are unique to 5 speed. I do not know how many versions there are. You could buy new parts - at least a few years ago.

For pu and t/a, the 5 speed will not bolt to a 4 speed bell housing used in pu and t/a. There May be a "dual-tapped" bell housing in the med / heavy duty IH trucks, but I have no clue about med / heavy duty IH trucks.

IH sv v-8 engines were externally balanced at the factory by "adding wieght" to the flywheel / flex plate. I do not know about the pressure plates. There is the possibility of "balance issues" if you swap a flywheel from one IH engine to another. There are other posts on this site about IH sv engine balacing.

IHPartsAmerica is very knowledgeable about IH sv engines.

 

[jeff campbell]

All very good info.now how do you tell the difference when they're siiting on the floor an bolted to a engine ? Jeff

 

[RobertC]

all very good info.now how do you tell the difference when they're siiting on the floor an bolted to a engine ? Jeff

Do not know...

A number of us on binderplanet tried 4 - 5 years ago, but nobody came up with any unique "marks" / "stamps" for a difference.

 

[MarkO]

I apologize for entering into this discussion so late in the game.

My first question is why are you contemplating the swap in the first place?

I have driven 'binders in sizes from scouts to prostars and everything in between.

I have logged many thousands of miles in loadstar and s-series chassis school buses and harvest trucks equipped with sv, mv, t444, and dt466 engines. I have even driven buses with rd and lv engines.

Imho I don't think you are going to gain much of anything by swapping out the sv304/4-speed and dropping in an sv345/5-speed. Yes you will have a few more horses and yes you will have one one gear forward. But the power band is such that you won't really be able to us it that much in a light line truck.

If you were talking about a loadstar and you were regularly going to be hauling ten tons those few extra horses and the extra gear would come in real handy. But a light line vehicle that fully loaded doesn't weigh as much as an empty school bus the differences in performance won't be that noticeable except for fuel mileage. The sv304 will always go further on a gallon of fuel than the sv345 and proably half again as far on a gallon of fuel than the sv392.

I have contemplated changing gear ratios to better take advantage of the power band of the sv304 in my Travelall. With 4.09 gears, pulling the trailer, it doesn't take much to have to grab third gear when I get up into the hills. Since I have to grab a third gear anyway I would prefer a comfortable third gear speed of 50-55 mph than the current 40-45 mph.

Adding a hamilton fuel injection kit with a modern electronic ignition system will do more to wake your ride up than to swap in an sv345/5-speed.

If I did ever swap in a 5-speed I wouldn't want the od. I would prefer the direct with faster rear gears. Deep low will pull all the stumps you want, even with fast rear gears. Od is an ineffcient way to do things.

 

[FDChappie]

I drive a '71 tette with a 345 t-36 and 3.54 rear gears. It is a good combination for towing and economy. It gets a real world 14.5 mpg and when towing if the engine gets bogged down just drop another gear. Looking at the size of the 5 sp I'd swear it weighs at least another 100 lbs more than the 4 sp.

 

[maxodyne]

Re: T-35 swap (T-36)

I have a 1965 ton 4 wheel drive truck. It is in awesome condition, and I use the truck frequently in my business. I want to swap out the 304 four speed with a 345 five speed t-35.I have the donor. I need some help with the transfer case shift lever possibly a bracket of some kind. The t35 does not have a place to bolt the lever on. Has anyone ever done the swap, and if so what was done with the lever.
Thanks, jeremy

I have performed this swap into my 1964 c1200 4x4, 304 v8 pickup truck. Donor truck was a 1971 d1200 4x4, 392 v8 Travelall. I have read all the threaded replies to the op (as of 21-dec-2012), so I will try to avoid duplication of information other than to clarify from my own experience. I believe this to be an IH t-36 transmission. 5th is direct, and 1st is approx. 6:1 gear ratio, as determined from counting input vs output shaft rotations before installing.

Clutch and flywheel:
I kept my 304 flywheel (flywheels are usually balanced for engine types). Used the 392 clutch disc and pressure plate ass'y as they were in better condition. Both are 12 inch. Both release bearings & collars were identical. I used brg & collar from the 392 as they were in better condition. From this you can deduce that the 4sp and 5sp input shaft diameters & splines are identical, but the pilot bearing dimensions are not.

Pilot bearing:
4sp vs 5sp pilot bearings are different. 5sp is larger, and my 304 flywheel had a factory spacer which, when knocked out, allowed for the correct pilot bearing to be installed (which was a 207 as I recall).

Bell housing:
4sp vs 5sp bell housing is different in two ways:
1. 4sp attaches with 4 studs; 5sp with 6. Engine sides of both are identical.
2. My clutch is hydraulic, and 5sp cross-shaft & bore are wider than 4sp shaft & bore. I used the 5sp cross-shaft with it's "dog leg" actuating lever which connects to slave cylinder. The dog leg compensates for the added width of the shaft. I made no changes to slave cylinder or its mounting.

Cross member:
I did not change the cross member. The c1200 and d1200 appear to be identical. I did use new IH bell housing to cross member mounts.

Transfer case lever bracket:
I tried to use the odd-shaped right-angle oem bracket from the Travelall, but I wanted to retain my original lever (that hulking cast steel lever from an old IH corn harvester I think). This would have put the lever in the wrong place with respect to the oem hole in the tunnel. I ended up using the original 4-speed bracket by measuring carefully, then drilling and tapping two 7/16" nf holes into the side of the transmission for bracket support. I used two 7/16" x 1/2" spacers between bracket and transmission to distribute stress and allow for lever movement. The previous owner had used a cutting torch to enlarge the tunnel hole for some reason (it's ugly, see photo xferhole.jpg, which shows the bracket positioning mockup prior to drilling and tapping). I was able to get the lever into roughly the oem location for this truck. Someday I will fabricate a small panel & weld it in place, meanwhile it works ok covered up with the floor mat (I live out in the sw desert so rain is not much of a consideration but snow is).

Transmission to body clearance:
the top (aka "shift tower ass'y") of the 5sp interferes with the tunnel cover on my 1964 c1200. The Travelall cover is a different animal. I fabricated a "trim ring" out of layers of plywood, and used this arrangement to raise the stock cover approximately 3/4 inch. I used longer ss screws to hold it down. This gives ~ 1/2 inch clearance in the tight spots, and I've yet to hear any banging/scraping. You can't see the additional height with the floor mat in place (see photo 5sphole.jpg).

Other considerations:

* I did this transmission swap in my driveway.

* 5sp is a heavy brute for a 3/4-ton pickup, around 250 lbs. I bought a transmission jack adapter to use with my hein-werner shop floor jack (made in usa). Safety first!

* transmission bolts to bell housing via 4 upper bolts thru trans flanges; 2 lower bolts thru housing. The latter are difficult to access thru bell housing vent. I used a 1/2-inch drive 7/8" crowfoot wrench to loosen/tighten (see photo crowfoot.jpg). Only workaround is to r&r trans with bellhousing attached, but that is too much weight/acrobatics for me on driveway. Note that lower left trans bolt (driver's side in u.s.) is thru bolt & you will release all the trans oil with this bolt. I used thread sealant for install.

* the jackshaft was shortened by approximately 4.5 inches & balanced.

* 5sp holds around 1.5 gallons of oil. I always use gl-1 mineral oil in truck transmissions and transfer cases (not hypoid).

* transmission has been in truck for 2 years now, and I love it. With that 304 and my vintage alaskan popup camper in the bed (camper weighs approx. 1700 lbs dry), having the closer ratios (closer than the 4sp) are great for on- and off-highway hill climbing.

* my 1964 c1200 4x4 now sports an oem 5-speed shift knob with a 5-speed transmission on the other end! I have yet to see another c-series pickup like it.

I also pulled the Dana 44 hd (large closed knuckle) axle out of the donor Travelall. I kept my 1964 c1200 oem 6-lug wheel pattern after the swap (donor truck was 8-lug). I can post my experience with swapping that into my 1964 c1200 if anyone is interested.

-- max.

 

[jeff campbell]

I have come to a conclusion on 5-speed identity now, with tranny's sitting on the floor...the od-I have outa loadstar, has no #592 on the passenger side case 1/2 way back & just below the top cover, like the 3 direct's ( outa pic' all's ) I have that do have the # 592 cast raised letter's on the side of the case....if I'm wrong then please let me know, or delete my post. Jeff c ( Robert c. ? )