Overdrive or Regular?

[rolling_Thunder]

So dont do the van OD... spend the $$$ on the passon kit.

Seems the guys on Moparts dont know how to build transmissions... Go over to the Dodge Charger and ask Chryco Psycho about them... he'll say he uses them all the time for drag racing without problems...

 

[696pack]

So dont do the van OD... spend the $$$ on the passon kit.
Seems the guys on Moparts dont know how to build transmissions... Go over to the Dodge Charger and ask Chryco Psycho about them... he'll say he uses them all the time for drag racing without problems...

I plan on it.

What you or others do is your business.

I think the info in the link I provided to Passon's OD unit pretty clearly spells out the strength AND the gear spread differences which are HUGH.

I don't care who rebuilds your trans, it is not going to increase the gear set or input shaft strength. The gear spread of the old OD unit is horrible for any kind of racing.

The old OD transmission is a poor mans answer for better mileage/reduce engine RPMs at highway speeds. Anyone using it in a real high performance application is just asking for problem and will eventually see them with that trans and any kind of hard shifting. If you want to coddle your car It will be fine, but that doesn't sound like the typical situation here.

 

[rolling_Thunder]

This convo has swayed from the original topic - I was simply stating to 69charger that for his application the OD transmission would be fine as he does not plan on racing...


I understand Passon says their kit is amazing... I admit i was incorrect with what i said about it being a copy of the factory OD stuff... I just don't see the point in dropping close to $3K when a well built factory OD will fit the bill for his application -

I have never seen personally the "weakness" of the factory OD transmission - never seen a shaft snap nor a twisted input... I am not saying this has never happened - just I have never seen it in the numerous cars I have done this swap in... The only thing I have seen is the cracking problem between the countershaft hole and the main shaft holes... which is a result from the loose tolerance from the factory... I always use a bushing which eliminates this problem.... No problems after that...

The gear ratios are different (already stated I was incorrect on this topic before) - I believe the typical big block making gobs of torque overs the splits quite easily - but I'll be the first to admit I'd rather lose a tenth at the track and save $$$ and go cruising -

Again - I was wrong - I didn't mean to stir up anything - I was simply stating for 69charger "why go with the passon kit?" when the factory OD would be alright for his application.

 

[rolling_Thunder]

I'm a fan of the Tremec transmissions myself... internal rail shifting rocks... We installed a Richmond gear transmission into the Car Craft Rambler and had quite a few issues - but now that it is in it runs great

 

[69 Runner]

Not everyone wants (or can) spend the kind of money it takes for a fat trans like that. They may not want that shifter protruding through their floor looking like it only belongs in a Pro Stock car instead of a factory hot rod.

Guess those folk PLANed on something else:edgy:

Why screw around with that junk, just get a good trans ..:grin:

magnesium case has an extra gear AND is a WHOLE lot stronger than the old iron pigs.

PS it shifts a tad faster and more solidly also...

 

[696pack]

Not everyone wants (or can) spend the kind of money it takes for a fat trans like that. They may not want that shifter protruding through their floor looking like it only belongs in a Pro Stock car instead of a factory hot rod.

Guess those folk PLANed on something else:edgy:

I agree.

I don't like the idea of spending the kind of money that Passon gets for his OD unit either, but it is the least expensive and least invasive to the car in terms of floor modifications. The Tremac while a better trans in terms of gear spread in the 1-4 is the best performance wise as well as a better OD gear, it is also the most invasive to the car in terms of floor modifications and the most expensive.

The Passon unit is the next best thing with regards to 1-3 gear spread and the OD gear, but absolutely no modifications to the car and less expensive.

The old /6-318 light duty OD unit is on the bottom of my buy list simply because the have a lousy gear spread and the inherent weakness of the trans. Yes, they are cheap, but that is because they are not very sought after. Also they are only cheap if you can use it as-is and don't have to rebuild it. If you have to rebuild it the rebuild cost is pretty much the same as rebuilding any 833, so why not apply the purchase and rebuild price to the cost of a Passon unit?

There are trade offs with all of them, there is no perfect senerio here. It depends on what an indiviual can live with and how much abuse you are going to give it and what you are willing to chance for damage.

 

[Meep-Meep]

I just picked up one of these aluminum OD units with the possibility of using it in my 69 RR with a 440 six pac. Some of the things I've been thinking about regarding the possible use of this trans in my car:

The gear ratios are not suited for any kind of narrow power band performance tuned engine, so cam selection is limited. The stock six pac intake may limit cam selection too so I'm sure something similar to a magnum cam would be best. I think a big flat torque curve is king with this tranny. Any of you ever driven a VW bug??

Replace the aluminum case with a cast one. The weight savings between the two on 3700 lbs of rolling stock is like peeing in the ocean. I'd rather have the durability.

Not too worried about the 23 spline. We ran plenty of those back in the 80's behind 440's in our street cars and beat the snot out of them. Adding slicks may be a different story, but on street tires the tires are the fuse.

 

[AmericanPowertrain]

Aluminum OD transmissions

I also hear that the aluminum case overdrive trannys won't take as much abuse/ horsepower as an iron case 833. Something else to think about...

First, a bit of background. My business offers up a ton of race built modern 5-speeds and 6-speeds for almost any Big3 powered ride, so I have lots of experience with OD transmissions. I am not trying to sell anyone anything, but I have seen plenty of smoking piles of parts to give a good opinion here.

I've got TKO 5-speeds with aluminum cases in cars with 900+ ft-lbs of torque running for a couple of years now without breaking the transmission. A webbed aluminum case will take a lot more shock load than a smooth casting. You can always throw a girdle on your aluminum 4-speed or 5-speed to keep the case from ballooning and spreading the shafts apart, a major reason for transmission death. Keep in mind that the overdrive gear is inherently the weakest gear, and the metallurgy that existed when the OE A833 4-speeds were built make them a pretty weak trans. The Passon OD 4-speed is very strong, reason being is they build their OD shafts and gears with the best technology available today. (I don't sell Passon, but they do make good transmissions). They only rub on the 4-speed OD transmissions is that the gaps between gear ratios are huge and there is not much OD. You just can't split ratios 4-ways and get a better result than splitting them 5-ways.

Also, running a little slip in the clutch or a fully sprung disc hub will go a long way to preserving the transmission. Solid hub clutches and street-twins with no slip are absolute murder on a transmission.

Hope all of this helps. AP

 

[696pack]

First, a bit of background. My business offers up a ton of race built modern 5-speeds and 6-speeds for almost any Big3 powered ride, so I have lots of experience with OD transmissions. I am not trying to sell anyone anything, but I have seen plenty of smoking piles of parts to give a good opinion here.

I've got TKO 5-speeds with aluminum cases in cars with 900+ ft-lbs of torque running for a couple of years now without breaking the transmission. A webbed aluminum case will take a lot more shock load than a smooth casting. You can always throw a girdle on your aluminum 4-speed or 5-speed to keep the case from ballooning and spreading the shafts apart, a major reason for transmission death. Keep in mind that the overdrive gear is inherently the weakest gear, and the metallurgy that existed when the OE A833 4-speeds were built make them a pretty weak trans. The Passon OD 4-speed is very strong, reason being is they build their OD shafts and gears with the best technology available today. (I don't sell Passon, but they do make good transmissions). They only rub on the 4-speed OD transmissions is that the gaps between gear ratios are huge and there is not much OD. You just can't split ratios 4-ways and get a better result than splitting them 5-ways.

Also, running a little slip in the clutch or a fully sprung disc hub will go a long way to preserving the transmission. Solid hub clutches and street-twins with no slip are absolute murder on a transmission.

Hope all of this helps. AP

I assume that in the bolded area you are speaking of the original Mopar built aluminum case 4 speed OD unit and NOT the Passon unit?

 

[AmericanPowertrain]

4-Speed OD

I assume that in the bolded area you are speaking of the original Mopar built aluminum case 4 speed OD unit and NOT the Passon unit?

Well, actually I was speaking in general. Let me say that I have the utmost respect for Passon and its products. They make some very, very fine transmissions and parts. That being said, the way a car performs based on gear ratios is not a question of quality but rather a question of physics.

If you look at the gear ratios of the Passon OD 4-speed you have a drop from a 2.66 1st to a 1.59 2nd gear, and 3rd is 1:1, for a 1.59 drop. These are pretty significant gaps. Generally speaking it is easy for the car to live with a long drop 1st to 2nd because once you have overcome the lack of inertia at a dead stop, the 2nd gear does not have as much work to do. A 2 to 3 drop is a little harder to take and a 1.59 drop into third is going to cause a lot of engines to fall on their face, especially given the curb weight of a B-body. In addition, the .80 overdrive gear only reduces the rpms by 20%, which does not knock the revs down as much as most guys are looking for. So you have big gaps where performance should be enhanced and a small gap where you should be cruising at low RPMs. This is not necessarily a deal breaker, but it is certainly not ideal either, especially considering that there are alternatives.

If you look at the TKO600, by comparison, the ratios are 2.87, 1.89, 1.28 and 1:1 with a choice of .82 OD for road racing and really agressive cams, and the much more popular .64 OD for cruising. You can see that the gap from 1 to 2 is still fairly significant, but as you move through the gears the gaps tighten up, ideal for performance. The TKO500 is often passed over because the drop from 1 to 2 is from 3.27 to 1.98, which lugs a lot of engines on the 1 to 2 shift. The TKO500 is handy for cars with tall rear gears (3.08, 3.23) and high revving small blocks that need quick RPM build to get to the power band quickly.

Admittedly, the biggest advantage the Passon has is that it fits just like the original transmission, which makes installation a snap. The TKO, on the the other hand it massively durable and has better ratios for the job. Five gears simply make it easier to split up the gear ratios for more performance advantage.

Hope I did not answer that one to death. :grin: AP

 

[696pack]

Well, actually I was speaking in general. Let me say that I have the utmost respect for Passon and its products. They make some very, very fine transmissions and parts. That being said, the way a car performs based on gear ratios is not a question of quality but rather a question of physics.

If you look at the gear ratios of the Passon OD 4-speed you have a drop from a 2.66 1st to a 1.59 2nd gear, and 3rd is 1:1, for a 1.59 drop. These are pretty significant gaps. Generally speaking it is easy for the car to live with a long drop 1st to 2nd because once you have overcome the lack of inertia at a dead stop, the 2nd gear does not have as much work to do. A 2 to 3 drop is a little harder to take and a 1.59 drop into third is going to cause a lot of engines to fall on their face, especially given the curb weight of a B-body. In addition, the .80 overdrive gear only reduces the rpms by 20%, which does not knock the revs down as much as most guys are looking for. So you have big gaps where performance should be enhanced and a small gap where you should be cruising at low RPMs. This is not necessarily a deal breaker, but it is certainly not ideal either, especially considering that there are alternatives.

If you look at the TKO600, by comparison, the ratios are 2.87, 1.89, 1.28 and 1:1 with a choice of .82 OD for road racing and really agressive cams, and the much more popular .64 OD for cruising. You can see that the gap from 1 to 2 is still fairly significant, but as you move through the gears the gaps tighten up, ideal for performance. The TKO500 is often passed over because the drop from 1 to 2 is from 3.27 to 1.98, which lugs a lot of engines on the 1 to 2 shift. The TKO500 is handy for cars with tall rear gears (3.08, 3.23) and high revving small blocks that need quick RPM build to get to the power band quickly.

Admittedly, the biggest advantage the Passon has is that it fits just like the original transmission, which makes installation a snap. The TKO, on the the other hand it massively durable and has better ratios for the job. Five gears simply make it easier to split up the gear ratios for more performance advantage.
Hope I did not answer that one to death. :grin: AP

Yes, I agree, however the Passon overdrive units first 3 gears are nearly identical to a 727 auto trans 3 gears. The auto trans shifts faster than the average man can shift a manual and is faster in the 1/4 mile in the same car. I don't think the gear spread is any kind of disadvantage for racing due to this. You run the quarter in 3 manual gears rather than 4 with Passon's OD trans so it is one less manual SLOW shift when comparing 1/4 mile times between the auto and manual car.

 

[696pack]

America power most these guys are auto guys and have a hard time understanding that keeping an engine in its power band, through the proper gear spreads, is real important in racing..and everyday driving...an 833 and 727 are compromises..

Mine is 2.62 first to 1:1 5th... as equal gear spread as Leo (GForce) makes...I adjust up and down with the rear tire diameter and ratio.. makes for a snappy drive...:grin:

I AM a 4 speed guy, and I do understand keeping an engine in the power band. The only auto muscle car I have had in the last 20 years is my LRET. Passon's OD trans gear spread is as follows:
Stock Overdrive
1st 2.65 : 1 2.66 : 1
2nd 1.93 : 1 1.59 : 1
3rd 1.39 : 1 1.00 : 1
4th 1.00 : 1 .80 : 1

I don't see any big problem with this gear spread.

As I said in an earlier post, ALL the choices have compromises. The PASSON unit is the best for ME. I don't want to cut my floor pan and have a not factory type shifter that draws attention to the trans. I want to be able to drive my 6 pack Bee on the freeway for 2 hours at a time without running at excessive RPMs. I have 4:56 gears and will be pushing it even with this OD unit. In fact, the 4;56s may be too steep for the 1/4 in 3 gears and I MAY have to go back to the 4;10s. I think it is right for me for what I want out of my car, but that doesn't mean it is right for others.

My car will be an occassional street driver and an occassional drag car that should run in the low to mid 11s and that is all I want out of it. I don't want it to be an unstreetable car AND I will be running A/C, P.S. and P.B.

I just don't think the Passon OD can be COMPARED to the original old Mopar OD unit with it's VERY wide gear ratio spread.

 

[69 Runner]

Interesting how Passon talks about the weakness of the O.E. O.D., but then compares their O.D. to a regular 4 speed's ratios.

Anyone know what the ratios of the O.E. O.D are? Isn't "4th" a .73 compared to Passon's .80?

 

[rolling_Thunder]

3.09:1 - 1.67:1 - 1:1 - 0.73:1

There is 1-4 in the factory OD... yes i know that 3rd is the OD gear but this is the pattern than the driver shifts into so for the sake of argument just accept this as truth...

in all honesty - the factory OD is great for a street car where ideal performance is not a huge deal - yes the first gear is a bit steeper than the Passon kit but you also get what ? 27% engine rpm reduction on the other end ? Works for my street cars...

 

[696pack]

3.09:1 - 1.67:1 - 1:1 - 0.73:1

There is 1-4 in the factory OD... yes i know that 3rd is the OD gear but this is the pattern than the driver shifts into so for the sake of argument just accept this as truth...

in all honesty - the factory OD is great for a street car where ideal performance is not a huge deal - yes the first gear is a bit steeper than the Passon kit but you also get what ? 27% engine rpm reduction on the other end ? Works for my street cars...

What kind of hp are you running in your street car?

 

[AdamR]

I have an iron case o.d. for my Dart. Time will tell if I like it or not but I wanted a car I can drive just about any were for a change.

 

[AmericanPowertrain]

Passon OD vs OE OD, con't

Interesting how Passon talks about the weakness of the O.E. O.D., but then compares their O.D. to a regular 4 speed's ratios.

Anyone know what the ratios of the O.E. O.D are? Isn't "4th" a .73 compared to Passon's .80?

The reason they make this claim is that the gear cutting and quality of currently available alloys give them a significant edge in strength over the original equipment OD. As I said in an earlier post, the OD versions of any of the older transmissions from the Big3 were suspect because the OD gear is inherently the weakest gear, there is more torque multiplication in OD and the alloys available back in the day were not nearly what they are today. That's why you don't see high torque muscle cars that came stock with factory OD, because a lot of the stock engines would have toasted them. Again, that does not make them bad transmissions, it just makes them comparably weak when you consider the non-OD versions.

 

[rolling_Thunder]

What kind of hp are you running in your street car?

safe HP lol I've put them behind engines making anywhere from a stock 375 to somewhere around the 650 range -

 

[AmericanPowertrain]

Saw Passon at SEMA

I spoke with Jamie Passon at SEMA a few days ago. Wow, what a straight-up guy. My company competes with Passon since we sell TKO kits for Mopars, but I have to say that I have rarely met anyone in the aftermarket business who treats people with as much respect and honesty as Mr. Passon. If you guys are considering a Passon transmission, you can feel confident that you will get the straight scoop from them. If you are looking to do a TKO, call us. :yes:

 

[696pack]

Well, since this thread is still alive and has somewhat run off track from the original poster's question, I will direct those interested tp this Moparts thread.

Here is a copy and paste from one poster there regarding this, but I also encourage people to read ALL of the peoples posts that have purchased both the Passon and Keisler O.D. units.

Having driven several Kielser equipped cars and a couple Passon trans cars, here's my .02.

1. For a true "no hack" install the nod CLEARLY goes to Passon
2. If you drag race you'll like the Passon, the Kielser is not a fast shifting trans, a bit too sluggish and notchy, especially at higher RPMs
3. If you want the strongest trans, Passons will take more HP than a Kielser by a fair margin
4. For cost and ease of install, Passon wins
5. For the best highway crusing O/D situation, Keisler wins due to it's better high gear ratio
6. Fuel milage Kielser also wins, same reason
7. Service - Passon hands down
8. With a 3:54 geared car that you do not want to modify beyond clean/simple easily reversable bolt ons and is mainly street driven and occasionally drag raced - Passon
9. For a modified car that is mainly used for local car shows, street cruising, taken on a good many long highway runs and not much else - Kielser
10. If considering these two companies you should also look into Gear Vendors and Classic 5 Speed before buying, may as well see what everyone is selling before you pull the trigger. I have also driven Gear vendor equipped cars, they should be a consideration for sure, they make a good product.

Here is the link to the entire Moparts thread:

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=4787748&an=0&page=1#Post4787748