Alright, in my research for doing a 700r4 swap, I decided to see what gears I have now. Based off the tech article http://www.nastyz28.com/camaro/camaro82.html

my car, with LG4, should have the 2.73 gears, but if I put my information down in a gear ratio calculator, we will use Summit Racing for this example, the numbers make no sense.

http://www.summitracing.com/popup/ca...tio-calculator

I have 25.9" diameter tires, and at 65 mph I am at a whopping 3700 rpms which would make the gear ratio a 4.51, what?

And if I try to find the RPMs based off my speed, tire size, and ratio, I should be at 2302.5 rpm, which I could only dream of with this car.

I know the previous owner never touched a thing with the drive train, and as far as I know, no one changed anything without my permission on it. When I have time I will pop up the back end and count tire turns vs. drive shaft turns but I thought I would ask in the meantime if anyone knows if I am just being stupid and not using the calculator right or is my rear end all sorts of screwy.

 

The tach is probably off, like they always are.

Pop the cover off and look. Nothing else is reliable. Obviously you need to do that anyway, as the fluid obviously hasn't been changed since you've owned it; if you had, you'd already know what gears it has.

 

The fluids have been changed, about a 2 years ago when I had the transmission rebuilt, but I forgot to ask the guy if he would check. I'm sure the tach is off a bit, but you can hear the engine is working hard at high speeds and would the tach really be off by 1000+ rpms?

 

Help us understand:

Your mouth forgot to ask your eyes?

Absolutely. Consider yourself lucky it's even THAT close.

 

either you have some steep gears, or,...OD/4th gear is slipping, or,....low on tranny fluid, etc.

can you describe the issue further? might help?

 

I didn't trust myself enough to rebuild a trany and had a shop do it for me for like $700, I wish I had just done the 700r4 then, but money was tight and this is my daily driver but you live and learn.

I'm still skeptical about taking apart a trany because I have little experience with them and don't want to trash the car, hence why I was going to do a raised up wheel spin to find the ratio, no taking anything apart.

I heard the tachs were bad but not that bad, I guess I might be investing in an after market one then.

 

Well there is no overdrive, this isn't the 2004r it's the 200c they used in 82 and 83 before they switched over to the much stronger 350, closest thing to 4 gear I have is a lockup converter that does damn near nothing to help. I'll check the fluid tonight but I am pretty vigilant about checking my levels and doubt that is the issue.

The issue is just; based off what came stock with the car and what ratio calculators show I either have an absurdly high ring and pinion for a 3 speed non strip car that was installed without my knowledge, my tach is way off, or I'm doing my math wrong. I really think it is probably the tach because if I had 4.51 I think I would take off a hell of a lot faster than I do.

 

So when you LOOKED AT THE GEARS, what were they, REALLY?

After all, that's all that matters.

 

Sofa, he has never seen the gears with own two eyes. Understand? Geez getting your transmission rebuilt by someone else does not make you a *****. The effort and time to money saved ratio is freaking huge on a tranny rebuild. Take the snide comments elsewhere.

 

Whats the tach rpm read at idle

 

with engine warm,choke off

 

Thank you g92, I didn't think I could get much clearer than what I was saying and Krisner, in gear it stays at around 700-1000 and in park it will be 1000-1250 when warmed up

 

I think what Sofa is saying is that if you pull the cover and check the gears, all doubt about what the car is equipped with will be put to rest. The following is from the 10-Bolt FAQ:

What Gear Ratio Do I Have?
Jerk the diff cover. The numbers are stamped on the ring and pinion. The RPO’s are usually found in the center console:
41 : 15 = 2.73 (RPO GU2)
41 : 14 = 2.93 (RPO GU3)
40 : 13 = 3.08 (RPO GU4)
42 : 13 = 3.23 (RPO GU5) / Approx. RPM’s at 70 mph--2133
41 : 12 = 3.42 (RPO GU6) / Approx. RPM’s at 70 mph--2255
41 : 11 = 3.73 (RPO GT4) / Approx. RPM’s at 70 mph--2463

JamesC

 

I can understand that, it would be more of a hassle for me to pull it off due to my lack of experience and it looks almost rusted shut too thats why I think I will just do the spin count on the tire and drive shaft.

 

It's always a good idea to remove the cover and look inside if that is an option. It seems like that is not an option for you, so turning the tires and counting the drive shaft turns is going to give you an idea of what you have. You must be careful and do it right or it will just confuse you more. If you have a standard differential then be sure that you hold one tire completely still and turn the other one exactly 2 full turns. If you have a good working limited slip differential then be sure that both tires turn exactly 1 full turn. Any mistake here is going to throw you way off. Get 2 people to help you so that you can keep an eye on both tires and the drive shaft all at the same time.

 

What actual size tires do you have? Is 3rd gear a 1:1 ratio in your car? 1982 automatic cars came with 2.93, 3.08, or 3.23 ratios.

https://www.thirdgen.org/1982-chevy-camaro

 

That has NOTHING WHATSOEVER to do with GEARS.

The way you find out what gears your car has, is to TAKE OFF THE COVER AND LOOK.

PERIOD.

It is inconceivable that something this simple and basic, can continuously cause SO MUCH ANGST on some people's part. It is not "hard" to do. Easier in fact than doing a brake job or tune-up or nearly any other typical DIY maintenance task. If the OP is capable of changing his engine oil, then he's capable of changing his gear lube. It's THAT EASY.

All the "spin the bottle" and "calculate" and "look up the codes" type stuff is actually more work and more trouble, not to mention less certain and therefore less accurate, than simply to TAKE OFF THE COVER AND LOOK. And besides, if you do any of the rest of that, you don't get to put new fluid in. What a deal!! What's not to like? What's to be afraid of?

I would strongly recommend that the OP not bother with any of that, but instead jump right in and go RIGHT STRAIGHT TO THE ABSOLUTE UNDISPUTABLE CERTAIN TRUTH. Not a lot of sense in dinking around with all the rest of that other monkey-motion that might or might not tell the truth.

 

tires are 215/70 14 so it should be 25.9 diameter tire, I think. and it should be 1:1 if I read right earlier. But the page you showed lists my car as having 3.23 gears and now I have conflicting results haha

 

I think Sunday I will try and pull the diff cover as I am getting conflicting results from different tech articles, it is the true way to know exactly, and I can get sofakingdom off my *** about it
will update you guys when I know.

 

 

Alright so looks like the hydraulics failed on my floor jack and I need a new one before I can check the gears...

While I'm at the store should I just grab a new tach as well? and is it just the tachs mechanism that is bad in our cars or an electrical issue? because I think I would just splice into the signal wire before it reaches the stock tach unless it is a bad electronic signal.

 

Looks like the tach is off as I do in fact have 2.73 in the rear, I will hopefully have a new pillar tach in by friday and can compare the too. I'm honestly a little scared of doing 3.73 with a 700r4 as my car gets 10mpg which didnt sound too off if i had maybe 3.23 but with the little ratio I have and a clutch converter it should be higher and I can't see it getting any better with a higher set.

 

Are you sure that this transmission is going into high gear? It seems like something else is wrong.

 

Can't be positive about the clutch converter but it does go into 3rd, before the shift kit was installed you could feel the cc kick in. After the kit was put in and I am driving around town I have to time letting off the throttle perfectly or else it will slam into the next gear hard when not at WOT and you cant feel any big drop in rpms after 3rd.But I agree something else is probably wrong as my 3rd gear is still a 1.00 which should be much better rpms and mpg than it is.

 

As a rough number, 26" tires should put you around (rear gear ratio x 1000) rpm at 70mph. So instead of 2730rpm at 70, you're seeing 3700 at 65. So yes you're about 1,000rpm off.

The lock-up should be easy to see working. At steady speed on level ground, holding the throttle steady, use your left foot to tap the brake pedal briefly. Assuming the TCC circuit and tach are working correctly, you should see a slight rise in rpm, then a few seconds later, it will drop back down as the TCC locks back up.

3.73 x .70 is 2.61. So you're not going to be making a huge change in lowering highway rpm by going 3.73 and 700-R4. However, the engine would have a LOT more mechanical advantage in acceleration from a dead stop, so you would, to an extent, be able to accelerate with less throttle and get slightly better mileage in city driving.

In a well-tuned CCC Q-jet car with 305 or 350, I've gotten 23 to 26 highway mpg with a 700-R4 and 3.42 or 3.73 gears. 3.73 isn't the only choice in gears of course. If your driving included 75mph highways, 3.42 is going to see mpg gains for sure.

Honestly, 10mpg means either your odometer is off (this is based on speedo gears being correct for the tire size & rear gear ratio) or you're driving impatiently or your car needs tuned for better mpg. Or a combination of all of them. You should be able to pull a little better in a low to mid 3000lbs car.

Good luck.

 

Wow thanks JMD, I'll try to test the tcc tomorrow.

I do mostly city driving but on the occasions I do drive the highway, maybe once or twice a month do a 80 mile round trip and that is easily half a tank, so the car kills the wallet. My speedo has had issues before with the head unit failing and then the cable grinding down at the cruise servo. The replaced speedo actually read 5 mph less until I went from 205 to 215 tires now its spot on, but I will go entirely off gps for mileage on my next fill up to test mpgs again.

I know 3.73 isn't the only gears but I want a driveable gear with a performance edge and 3.73 seems to be the gear ot choice for many in that area.

I am fairly sure the q jet is tuned well but I have never tuned it myself, I will learn to at some point as it is harder and harder to find a mechanic nearby that can do it.

I do have a bit of a lead foot, a little hard not to in this car but after a few too many high speed tickets I am learning to ease up.

Much appreciated for the many points you gave!

 

I should also note that I don't plan on staying with the carb. Once I find a complete and understandable write up on the process I want to swap to a tpi set-up which I believe would help with both mileage and performance.

 

I would not do that...

TPI will NOT give more performance than a carb. Better mileage, maybe; but people aren't swapping carbs onto TPI cars by the thousands because TPI has such a ground-pounding power potential.

EFI in general would be a different matter, than TPI specifically. If you don't already have a complete TPI, a better option, that will run harder and in the end cost less while giving all the same benefits that any other EFI system will, would be the Stealth Ram.

 

I had my eyes on a ram jet and stealth ram but they are very pricey and I thought they say they are smog illegal.

 

Yep. You could swap for inspection time or run a Super Ram or T-Ram.

I went from L69 4bbl to TPI swapped on and it's disappointing.

 

I went from 2.73s to 3.42s and a Eaton posi. unit with my 700r4 and for around town there perfectly in sync with the 35/40 mph roads around here in drive. It stretches them just enough without over revving. I don't think the 3.73s would fare as well and may want to over rev. at even those speeds in drive.
I love the 3.42s and they made a tremendous change in performance with the car.

( I say in drive because that's what I use around town. Overdrive is used for speeds over 40 MPH/highway)

 

It has crossed my mind to just do a swap for inspections. But then again idk if moving to a smog testing state is going to happen so I will see.


I have been thinking of going lower than 3.73 just for the mileage because that is a big part of why I want to swap. Anything should be better than 2.73.

Btw, jmd, it looks like my tcc does not engage. The shop that I was going to have install the trany was saying they didn't think I would need it on the 700r4, but I would prefer it if possible to get all the mileage I can.

 

TCC is a pretty simple circuit.
Figure out what wire from the PCM commands it and put a test light on that circuit to see if it's signaling for it to lock-up (after the ECM sees a certain speed, temp, and steady TPS) The logic for it in the service manual would walk you right through it.

With stock type oiling flow, the 700-R4 should have lockup used. Anything that cuts heat and reduces rpm even a small amount is going to help your trans. life and mileage. Small amounts, but it sounds like you actually put some miles on your car.

Sure you don't wanna go 200-4R?

 

This is not directed at anyone particular . Unless you have the means to fork out $1,300.00 (estimate including installation)to build a modified/upgraded 28 spline 10 bolt with new parts. Thats doing the upgrades that IMO need to be done while you're in there . Or even more for a modified 9in. or 12 bolt you won't have to worry much about swapping gears. I'm not trying to be discouraging but every time someone mentions swapping gears (ring and pinion) it reminds me of how there is so much more to it than is sometimes expected.
Then there's the 4th gen. swap that seems to be available but as with the first option you rarely hear of it being done on this board.

 

I'll see what I can do, granted, the Tach could be off like said earlier, so once I have the new one I will test again.

I will be doing a trans cooler on this as well just to help with the life. I don't put tons on maybe 80,000 in the past five years, so about average for a daily driver. but the money I would spend on a 200-4R that can withstand some power would be way out of my price range haha. I want this Camaro to be at at least 500 hp and torque in the next few years. Granted the idea of a T56 has crossed my mind over and over too.

 

Well this stock 10 bolt will only be a temp until I can afford to do a Moser or Strange high spline (30 -35) axle rear end. I can get the larger ring gear ( am going to stay away from a spacer) for a series 2 for roughly $150 and installed with a posi carrier for $200, but I feel I may be able to swap a carrier myself, as far as I can tell its just remove the c clips, pull the axles and swap.

So this will be a budget job to hold me off for a few years of minimal hard work, just a little burnt rubber and a couple races on and off the track. I know how hard it is gonna be to save up and that's why I just want something simple to work until I have the time, money, and skills for a big swap. If I won the lottery tonight I would be going all out on the car in every way but I'm planning for the worse and hope to earn some of my money back by doing the 700R4 first and see how things go from there.

 

It sounds like you will have a really nice ride. It’s always great to have someone dedicated to working on their car. Anyone that's willing to learn along the way and can have fun doing it, even through the tough times.
Here’s a little something I found concerning the gear swap =

The shop that did mine gave me a three year warranty on parts and labor aslong as I did not run slicks/drag tires.

 

Changing the differential is not just a simple swap. You must measure the backlash before you remove the original differential and then shim it to get the backlash and bearing preload the same when you put the new differential in. http://www.nastyz28.com/forum/showth...t=install+posi

 

Thanks BGH! I would have probably just swapped them without a care in the world and destroyed some things

I'll have to see if I can rent the tools needed for this as I still think it will be cheaper than going to a shop, even though I pay for the warranty too.

 

And thanks ronusmc, I watched that a few nights ago but fell asleep gonna watch it again and learn everything haha

 

New tach is in and I am at 2500 rpms at 65, not sounding so bad anymore haha thanks for the help with everything guys!!