84 grandnational transmission

[carcrazy2332]

I have a transmission out of a 84 grandnational.I know it will fit an 87 grandnational.My question is ,will it perform the same as the original 87. I am going to rebuilt it but i dont want to invest in it and it wont work the same as the 87 trans.

 

[jdpolzin]

The BQ and BRF trannies both work well. We use either valve bodies in our cars and dont notice any difference in performance. As far as the actual differences, you'll need to contact a tranny builder that sees them everyday.

 

[carcrazy2332]

Thanks for the info.

 

[LOT]

BQ will work fine

Remove the spring from the large weight on governor.
Replace servo with a BRF or after market.
Your car will never know the difference.

 

[carcrazy2332]

Will take your advice,thanks.

 

[standupjskiguy]

84 Trans

We have an 85 T-Type and an 87 Gnat. The Gnat's 1-2 shift is much much firmer than the 85. The 85 even with a shift kit will not chip the tires. I actually
like driving the 85 because it doesn't jerk my head back when it shifts.

So now I have a question, is an 85 trans a BQ trans and the 87 is BRF? And the only difference is the servo and the governor spring?
The BQ and BRF is the GM code number?

 

[LOT]

yes

We have an 85 T-Type and an 87 Gnat. The Gnat's 1-2 shift is much much firmer than the 85. The 85 even with a shift kit will not chip the tires. I actually
like driving the 85 because it doesn't jerk my head back when it shifts.

So now I have a question, is an 85 trans a BQ trans and the 87 is BRF? And the only difference is the servo and the governor spring?
The BQ and BRF is the GM code number?

84-85 GM code --BQ--this code will be on side of trans (tag)
86-87 GM code --BRF
The internals of the valve body have some slight differences---not enough that you will notice.
The reason your 85 shifts softer than your 87 is not because of VB. Could be many thing-- line pressure--different shift kit.

 

[standupjskiguy]

84 Trans

Thanks for the code number info.
I disagree though about why the 85 trans shifts softer. Your explanation implies something might be wrong with the 85 trans. It has been that way since we bought it new and for 140K miles with no problems whatsoever. I tried installing the shift kit while I had the dreaded TCC sticking problem before I learned what was really causing those symptoms. I wasn't really trying to firm up the shift but the simple shift kit I bought made little difference in the 1-2 shift.
I think someone who has owned both a stock 84-85 and then an stock 87 would confirm my observation about the differences in the way the transmissions shift.
I thought I read somewhere that the 87 trans has a different accumulator piston circuit on the 2nd gear accumulator and that the accumulator applies faster making 1-2 shift is super firm.
I understand many things can effect the shift but I think there are perhaps more differences in these two trannys than just a BFR servo and governor spring.

 

[LOT]

I DID NOT imply something was wrong

Thanks for the code number info.
I disagree though about why the 85 trans shifts softer. Your explanation implies something might be wrong with the 85 trans. It has been that way since we bought it new and for 140K miles with no problems whatsoever. I tried installing the shift kit while I had the dreaded TCC sticking problem before I learned what was really causing those symptoms. I wasn't really trying to firm up the shift but the simple shift kit I bought made little difference in the 1-2 shift.
I think someone who has owned both a stock 84-85 and then an stock 87 would confirm my observation about the differences in the way the transmissions shift.
I thought I read somewhere that the 87 trans has a different accumulator piston circuit on the 2nd gear accumulator and that the accumulator applies faster making 1-2 shift is super firm.
I understand many things can effect the shift but I think there are perhaps more differences in these two trannys than just a BFR servo and governor spring.

If you would have read closely you would have seen that I stated the servos were different--that alone is a major reason for a firmer 1-2 shift. That and 140K.

 

[84BuickGNYorkPA]

I've had both..... 84 was more of a lazy shift for sure, guessing the power in front of the tranny had a dirrect effect on the shifts also. (87 motor and tranny would allow me to light up the tires at will/84 motor and tranny not so much)

Chuck