can someone tell me what transmission that would be in my car??? I think its a 3 speed??

 

Here is a pan ID chart Scooter. Should be #3 or 4.

 

thank you sir...must go and check!!

 

13 bolts and the pan looks like # 3

 

The reason im asking is because since I rebuilt the engine last year I fine the car does not have the snap I think it should have!!


Im starting to wonder if my torque converter needs updating.....
new comp cam 262h mild cam
10;1 sealed power pistons
3.08 rear
750 cfm carb


anyone have any positive input .....would my stock converter be ok with my setup??

 

I don't know for certain about the '71s, but the '73 and '74 B- and C-bodies didn't get TH350s, they got either the TH375 or TH400.

The TH375 is a "downbuilt" TH400, with a TH350-sized slip yoke and output shaft.

That TH350 may not be original.

- Eric

 

Actually, the 1971s got a TH375B, which is an "upbuilt" TH350.

 

I forgot about the 375's, but they had T400 pan didn't they.

 

The original TH375 was externally identical to a TH400 except for the smaller output shaft. The TH375B, as used in the OP's car, looked like a TH350, including the pan.

 

So, Joe, are you saying that the '71s got the TH375B, while the '73s got the TH375A?

Because I know that the '73s got the TH375 that looks like a TH400.

- Eric

 

Well tonight I decided to drop thr trans pan......It is a th400

I sure whish they would have put a drain plug in these pans...messy job!!


So now that im into the trans for oil and filter is there anything else I should be looking for???


The round thing on the passenger side of the trans that had the vacuum line that goes to the TCS.....is this something that gets replaced after time??? was the th400 a good trans???


I know nothing about transmissions so any help would be great!!


image_zps19cdade5.jpg

 

Yeah, it's always a "cleansing" experience to take a Dextron bath.

There is nothing else you should do or be looking for.

There is no need to touch the vacuum modulator on the side on the trans, unless it's not working. Attach a length of vacuum tubing to it and suck on it - it should pull in, stop moving, and hold vacuum when you pinch off the hose.

"Was the TH400 a good trans?"
That's like asking whether the M1 was a good rifle.
It kicks butt, and pretty much can't be killed.

- Eric

 

Installed the new trans filter tonight and for the love of god I should have paid more attention when I removed the filter tube with the o-ring.


It took me the better part of 1/2 hour on my back trying to figure out how it went back with those alignment tangs.....but after a quick look in my manual I figured it out lol.

 

Great!

As a wise man nice said, "If all else fails, read the directions!"

- Eric

 

Did you weld a drainplug? So much nicer to change oil in the future

 

Roger, now that you got the tranny fluid changed - whatever you do make sure you don't create a leak by over tightening those bolts. Follow the pattern in the CSM and torque values. If you want to make sure they don't come loose? Just use a little bit of thread lock on each one (Locktite Blue - 242 is a good choice). I believe they are only around 10-14 ft/lbs.

I have to say this and it may be something you won't like. I'm not totally convinced that your giddy up problem is the transmission - yet. You indicated after the rebuild that the engine just didn't have the oomph/power/torque it used to before the rebuild was done. All things being equal, if the trans was delivering set value engine torque BEFORE the rebuild, it will continue to do so AFTER the rebuild unless it's got catastrophic failure. The torque converter hasn't been changed, and you found no evidence of contamination or filings in the AT fluid, right? The TC won't just go bad. So the only thing that was changed was the 'engine performance'. Did you dyno the engine to determine the HP and torque values?

If your rebuilt engine has significantly higher torque and hp than the factory? THEN you might be looking at a new TC with a higher stall speed to get the launch you're looking for. Check your cam specs to see how it would affect your eng performance before you start tearing your tranny apart.

That is a GREAT idea!

 

Did you degree the cam? I didn't one time and the engine didn't have as much low end power as I expected. Checked the cam and found it was 8º retarded.


I think it should be OK.

 

That cam should work great with the stock converter. If the car doesn't have the get-up-and-go it should Id lean more to some tuning issues. Whats the timing set at? How is the timing curve? Is the carb tuned correctly? Double check this stuff before suspecting a converter issue.

 

Added new trans fluid tonight and no leaks as of yet allan!!! Its too cold to take the car out for a run.....feels like -27c with the wind


As for the converter...not going to touch it right now. In the next week or so going to jack up the rear axel and remove the diff cover and see what gears are in there and order up my 3.73 gears and posi carrier!!


I think the car came with 3.08 gears........what else should I need to know before I order up the goods.......Are my stock axels are 28 spline...is this correct....diff cover is 10 bolt


thanks

 

Roger, the L31 equipped Royale in 71 came standard with 2.73:1 axle and had an option for the G94 2.93:1 I'm guessing your car has the 455 4bbl? If it's the 455 2bbl originally it only came with a 2.56:1 standard rear axle.

If you're planning to change out the carrier and gears, you should be able to confirm the gearing by checking the numbers stamped on the edge of the ring gear.

10 bolt refers to the number of bolts that hold the ring gear to the carrier, not the number of bolts on the diff cover.

Why would you put 3.73's in that car? Even from the factory they only offered up to 3.08:1. 3.73's would give you insane rpms and lousy fuel mileage.

 

Allen is right even a 3:23 will wake up a set of 2:56 s and still be a good all around car . I have 3:90 s and it kills me to run over 60 with them .

 

Not to worried about the gas thing Allan.....just want it to be a fun car to drive....tire shredding machine....lol

 

Removed the rear diff cover tonight and this is what I found......the gear is 10 bolt......and then there is a bunch of numbers which I think the 4....13 are the numbers im looking for????? what gears do I have???


































GetAttachment_zpsb3f702a6.jpg

 

Need a better/bigger picture of that gear set numbers. There should be a whole series of numbers stamped along that edge.

 

here ya go Allan...its stamped twice....one spot is 40 13 the other is 4 13

DSC08321_zpsc402616f.jpg





DSC08317_zps6e2ad84e.jpg

 

Not a expert, but since you have the rear end apart, I find the easiest way to check your ratio is to mark a gear on the ring gear and the pinion and count them then divide. So if your ring gear is 40 and your pinion is 13 then 40 divided by 13 is aprx 3.08.

 

The numbers you want are 40 and 13. As Greg says, 40/13 yields 3.08:1 gearing. That's a respectable gear that gets performance and a bit of economy. I almost went that way, but instead now have 3.42:1 posi in my car. Have you considered that option or 3.55 instead of 3.73's?

Did you ever find out where your power band is on the new engine? I still think if you changed the hp/torque you might be able to get away with just changing out the TC to one with a higher stall? If there's no change to the engine specs, then by all means go with a change to gearing. FYI, changing the gearing will also require you to change out the speedo gears. Here's a neat Link for your consideration

 

so Al is my gear 8.5........If im going to order up some parts for this I don't want to order the wrong stuff


1. 28 spline posi carrier
2. 8.5 ring gear....3.73

 

28 spline should be correct for 71 and 72 with an 8.5 rear. The ring/pinion gear must also be 8.5 in whatever gear combo you want. May I suggest you give Jim Mitchske a call and discuss your options? He specializes in this stuff and provided me with my carrier. He goes by Monzaz on this site. He also sells carriers/gears so that might work well for you?

 

Today I decided to try out my new sand blaster from princess auto!!


I think it worked pretty good I did the rear diff cover,,,it has some numbers on it....not sure if it means anything.....1234493
image_zps07104dba.jpg
image_zps8ef2d80a.jpg
After paint
image_zps99dc0292.jpg

 

Roger, looks good!
What sand blaster did you get - the table top or floor model. I tried the bench model but it really didn't seal well so I went to the floor model and have never looked back. What media are you using? I like the glass beads myself - heavier grit for tough blasting and fine grit for finishing. And...your compressor is handling the CFM requirements ok?

You're also using exactly the same paint I used on my axle housing to make it look like an aluminum housing!

Felpro makes a really good gasket for that housing and it's not expensive. You can get it at Canadian Tire for around 8.00 or so. I used the crappy one that came with my W27 cover, and ended up re-doing it with that felpro. I also used some permatex2 to hold the gasket and seal the unit up. So far it's been 5 months and no leaks.

I'm surprised your wife is letting you buy stuff right after the baby was born. You must be driving her nuts in the house...congrats again on your son!

 

Hi Al I bought the bench top one.....price was right $99 and I bought a bag of the fine glass beads...should have went with a little course grit!! My compressor on the other hand is too small its a 8 gallon 3.7 cfm that I have it piped to a 20 gallon tank which give me 28 gallons.


As far as the wife ....we have been staying at my inlaws for her recovery and she is doing great...My little boy is doing great..could not have asked for a better Christmas gift!!


So ive been back and forth to the house doing a few things,.....snow clearing/car stuff

 

Honest, I hope that 20 gallon pig works for you but I don't think it will unless you're just doing a lot of really small stuff. Sandblast cabinets eat air like you wouldn't believe and you need at least 90-95 psi at around 15CFM to really make it work.

I remember the first time I used my bench model and it was a feeling of accomplishment compared to the wire brushing I'd been doing. Then it just fizzled as I tried to do larger parts that needed sustained air. Costco had a sale on Snap on 20 gallon oil compressors for around 250.00 so I bought that and tried it out. It was an improvement over the 3 gallon porter cable I had from years ago but still couldn't provide the CFM I needed for blasting.

I took the bench model back to PA because it was too small, and it leaked like a sieve around the foam seals at the top. The viewing window also got clouded up really fast. The new floor model holds much larger pieces and is a breeze to drain/refill with beads. Only issue I ever had with it is one of the gloves seams came undone and it felt like needles jabbing my arms in there. It was replaced under warranty with no fuss or bother. One thing these cabinets really need is a strong light built into the cabinet. I use a rechargable LED with a magnetic base to see what I'm doing. Works well.

If you keep your eyes peeled, the floor model (like this one I got) goes on sale periodically for 188.00. Regular price is 399.00 but to be honest even at 188.00 I feel it's a bit overpriced. One thing it does well is allow shop vac to be hooked up for air flow so you don't end up with dust in the cabinet. I also bought one of their PAL 60 gal single stage compressors (needs 230V). It delivers everything I need. Only thing that's gone wrong with it is the air line from the cutoff valve blew off. I got PA to warranty it with new parts the next day and it's still good as gold. The big compressors go on sale too. Mine cost 1 large, and 3 weeks later it was on sale for 749.00 so I got the difference.