76olds

Hey guys I have my headers in and rear 3:42 posi in as well, I'm finding the car is shifting before I turn a corner. Unless I'm on it doesn't shift till later, I also seemed to have lost the kickdown passing gear around 50mph. Is this due to the rear change? Also my speedometer seems way out of I'm 80mph on my speedo but no where near 60mph. Any thoughts ?

Fun71

Yes.

Speedo recalibration is always necessary after a gear swap. Also, if you don't already have a tachometer I highly recommend installing one as it will let you know if the trans is shifting at the proper RPM. The MPH where the shifts occur will be different but the RPM should be the same as before.

76olds

Thanks Kenneth, I don't have a tach I will have to put in an aftermarket one. I read about some color gear I need I'm going to try to check it out and see if I can get one. I just find its shifting very quickly now from a stop. If I step on the throttle hard it won't shift until later but an easy start it shifts almost instantly. I just figured it was the rear gear change. I'm trying to read more on this. I thinking it may be timing now I put the headers in just not sure yet.
Eric

hookem horns

On the speedo gear, I went with a ratio adapter instead of having to change both the drive and driven gear. You can only change the driven gear at the end of the speedo cable by so much without also changing the drive gear in the tail. The ratio adapter installs in 15 min even if it costs a little more than changing both gears. Use a GPS (phone apps are free) to find our the exact % you are off. Search the PATC site for allowable drive/driven gear combos and ratio adapters.

ThePackRat

Make sure the kickdown cable is adjusted correctly.

And you will want to get acquainted with the governor in the transmission.

Much like how the weights & springs in a distributor play a part in ignition timing & advance ... the weights & springs of the governor play a part in the shift points.

A governor that was originally designed to be coupled to something like 2.41's is never gonna play quite right with 3.42's.

76olds

Put-r-ther thanks guys, I will check into both, I'm going to take it back into where I had it done and ask the proper questions, I picked the car up early Saturday and buddy said it was good to go, so off I went.
So I will have him check the governor on the trans, the kickdown cable, and the speedo ratio, can I rule out needing a better or new torque convertor?

Fun71

I didn't have any issues when I swapped from a 2.56 rear to a 3.55 rear on my '70 Supreme (actually I used the same governor for 2.56, 3.08, 3.23, and 3.55 rears with no issues). Sure, it shifted faster/sooner/at a lower MPH but the shifts were at the same RPM as before. That RPM is reached at a much lower MPH, which is why the shifts occur sooner. WOT shifted at 4800 RPM for all gear ratios as well.

76olds

Thanks again Kenneth, I spoke to my buddy who did the job for me and he also said that the governor won't need to be changed, He has the new gear for my speedo cable so my MPH will be back to normal, Also the powermaster starter does have a louder cranking noise to it so no issues their as well. He figures my timing is out so he is going to curve the distributer and set the timing.
I will let you guys know how it works out .
Cheers thanks for the help.
Eric

Beob

Do u have an adjustable modulator? If so u can change the point at which it shifts.

76olds

I do have an adjustable modulator yes, It was set to the shift kit that was installed, It seems to be working fine. I'm getting a nice chirp out of second gear if I stand on it , just starting out slow off the line isn't quite rite yet .
Thanks Beob
Cheers Eric

oldcutlass

The modulator does not change the sift point much, maybe +/- 5 mph. As stated above if you want to change the shift points you'll have to modify the governor weights. If your passing gear is working when you floor it then the cable is fine.

76olds

I have no passing gear yet Eric, I'm not sure what the deal is, It was ok before they put the headers and exhaust in along with the starter so I guess ill just wait and see. I just dropped it off at the shop again tonight and buddy is going to adjust it along with a few other things.
Thanks for all your help!!
Cheers Eric

Fun71

Do you have any kickdown at all?
From this statement, I thought you meant at 50 MPH it doesn't kick down like it used to, which would make sense if the RPM is above the downshift point and it would just stay in 3rd. If you don't have a kickdown at any speed then the cable may not be hooked up.

It could also be related to your shift kit, as in there may be an issue in the valve body.

oldcutlass

Hopefully it's just the cable.

76olds

It doesn't seem to kickdown at highway speed, The cable is there , not sure if just needs to be set, It seems to shift ok just no passing gear at all. I just didn't feel up to getting into checking it out I just brought it back to the shop. I'm a little tired these days. I hope its just the cable as well.
I've already spent too much on the car this year my wife is screaming , can you hear her lol.
I will know more tomorrow, I will post the crazy news then.
Put-r-ther thanks for the advice and help !!!

76olds

Also the wife and I went to Dairy Queen last night and when I left the parking lot and got on the highway I stood on the throttle It went like hell and squawked out of second with that new rear gears It actually shocked us being that I was told I could have an anemic 7.8.1 could this be possible? , I'm not sure if the transmission would do that if it were on its way out. But I could be wrong.

ThePackRat

I went thru a similar thing years ago.

I had an 84 Cutlass that was originally a :

307
TH200
7.5 with 2.14's.

What I ultimately ended up with was :

Rebuilt 79 403
Rebuilt 77 TH350
GN 8.5 rear with 3.42's.

The rear change was the last thing to happen.

As incredible as the gear change was, once the excitement wore off some ... the early shifts started to bother me.

Sure it worked as it was ... but like you I felt as if it shifted too early under part throttle acceleration.

I sold the car before I ever tweaked the governor ...

But I'm fairly certain overall part-throttle driveability would have improved by moving the shifts up some.

To me holding a lower gear a bit longer (within reason) makes better use of the power the engine makes.

I found that I was pushing my foot down farther to try & keep it in a lower gear sometimes.

This just didn't seem natural to me.

It got to the point where I was starting to row thru the gears on my own in what I felt was the right speed/rpm to upshift.

Not only did the car feel stronger & more natural ... I can't help but think it was probably slightly more efficient vs my walking deeper into the pedal all the time trying to prevent an upshift when I didn't want it.

Of course' all bets were off if you were simply pounding on it ...

Shift points at full throttle weren't that bad.

ThePackRat

Gears can do amazing things.

I have a 1984 H/O road test around here somewhere.

Those were rated at like 180 HP & 245 TQ.

Stock tire size was 26 inches tall with 3.73's out back.

It managed to do 0-60 in like 7.9 seconds from what I recall.

Fun71

You need to check it at 30 MPH or so. 50 MPH may be at an engine RPM that is above the point that the governor allows a downshift (all cars have this point, it's just at a very high MPH for the 2.41/2.56 ratios). If it downshifts from 30 MPH then it's working as it should and you just need to recalibrate yourself to the new gears.

tmaleck

I say tweak the governor. I had this issue with my 67 when I put the 4.10 rear end in. I used the lightest weights and heaviest springs (closest to stock) in the governor mod kit. Worked great, car is super drivable with good shift points and a properly adjusted tv cable. I posted on here back when I did the work.
Tim

matt69olds

B&M, TCI, etc, all have a govonor recalibration kit for dialing in the govenor. I would suggest using a differant govenor to modify, that way if you really get the combination of weights and springs hoplessly messed up you can go back to stock. Take careful notes, be prepared for lots of trail and error.

olds 307 and 403

I have 76 Olds 350, 7.8 or 7.9 to 1, depending on clearances in my Cutlass with Sanderson headers and 3.42 gears. With the stock stall and slightly better first gear, rubber is no problem.

76olds

Appreciate all the feedback Guys, I was at the shop tonight and there was a problem with the vacuum modulator. The diaphragm was done so its was replaced. The only problem is the ear that holds the bolt in for the modulator broke off so we have to fabricate something up to hold it in. The distributer is now curved and the timing is set so I guess I'll see how it preforms on Friday. Buddy still doesn't feel as thou the governor needs to be done.
Cheers guys thanks, I will let you know how it performs later this week.
Eric

76olds

I'm hoping to get the same out of my 76 without dropping in a rebuild. I will be quite happy with leaving it as is with just the refresh and changes I have done.

matt69olds

The bolt snapping off in the case is a common issue. It would be pretty easy to fabricate a clip to hold it in place.

You can order a clip that uses a pan bolt to hold the modulator in place. Its available from TransStar. Head to your nearest transmission shop and ask to look through their catalog.

76olds

Thanks Matt, I will have a looksee today for the clip at mister transmission only half a hole left nothing to bolt to , would save me bending one up and drilling holes in some sheet metal.