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Tranny swap.

vr6freak

New member
Joined
Feb 14, 2016
Hey guys. Guess maybe the performance section may not be the right spot so move if needed admin.... I'm wanting to swap an auto with the tallest gearing possible into my 79 245. I found a low mileage tranny from a 1994 and was curious if it would be a straightforward swap ? I read 91-95 Have roller bearing tailshaft and obviously locking torque converter..
 
The transmissions with the locking converter are those ending with "L". (AW72L) found on 16v 7 and 940 cars from the very early 90's They have different gearing than the standard AW70 and 71 variants.

Converter ratios:
AW70L 1.72:1
AW71L 1.72:1, 1.80:1
AW72L 2.40:1

Stall speed:
AW70L 2,000
AW71L 2,000start-2,700 stall, or 2,500
AW72L 2,500

Gear Ratios
Gear_____AW70/71______AW72L
1st______2.45__________2.83
2nd_____1.45__________1.49
3rd_____1.00__________1.00
4th_____0.69__________0.73
Reverse_2.22__________2.70

https://en.wikipedia.org/wiki/Volvo_AW70_series_transmissions
 
I swapped an AW71L from a 94 on to my B21A with no issues. The lockup function is HORRIBLE unless you've got a 4.10 rear end, but if you don't actually drive your car for fun, it might be tolerable.
I deleted the lockup function at the valve body, and everything is way better now :).
 
IF it's that, there's no way that buying a trans with better gearing pays for itself in MPG (or better, GPx1000M) unless you put like... 50,000 more miles on it.
 
Thanks for the input guys. The reason I'm looking fir tall heading is , I got this car to drive while I'm building another one but I have two cross country trips planned soon and with the old 3 speed the car is screaming at 85 mpg. The car is mint so I don't mind putting some money in it and in my area volvo parts ( like low mileage trannys) are cheap and easy to find. It's not a sports car so I figured why not leave it auto so I can text and sip my Starbucks like everyone else ��
 
I swapped an AW71L from a 94 on to my B21A with no issues. The lockup function is HORRIBLE unless you've got a 4.10 rear end, but if you don't actually drive your car for fun, it might be tolerable.
I deleted the lockup function at the valve body, and everything is way better now :).

Can you
Make a switch to activate the lockup ?
 
Unfortunately no. It's a mechanical lockup, driven by hydraulic pressure.
For me, I found that my B21 (T) just didn't have the torque to lug the car up even a slight hill with the lockup on a 3.73 rear end. It would downshift (violently) from lockup straight to 3rd gear, bypassing the O/D completely. The revs went from below 2000 to all the way above 3500, just to get up the incline. Passing someone on the highway was aggressively violent too, since it would again downshift to 3rd.

If you can get the later transmission, or already have it, give it a try. If you don't, and can find a regular AW71...get that one. All this is my opinion though, so take it with grain of salt. I'm MUCH happier with the car now that I have no lockup :).
 
Unfortunately no. It's a mechanical lockup, driven by hydraulic pressure.
For me, I found that my B21 (T) just didn't have the torque to lug the car up even a slight hill with the lockup on a 3.73 rear end. It would downshift (violently) from lockup straight to 3rd gear, bypassing the O/D completely. The revs went from below 2000 to all the way above 3500, just to get up the incline. Passing someone on the highway was aggressively violent too, since it would again downshift to 3rd.

If you can get the later transmission, or already have it, give it a try. If you don't, and can find a regular AW71...get that one. All this is my opinion though, so take it with grain of salt. I'm MUCH happier with the car now that I have no lockup :).

The tranny I was planning on getting is from a 94 940 I believe. I didn't see a button on the shifter. It maybe I'll do a little more research before pulling the trigger .. thanks for the input. I'm sure my little b21 non turbo would struggle too . So should a get a tranny with overdrive but no lockup or did they make a lock up on a non overdrive? Lol
 
Thanks for the input guys. The reason I'm looking fir tall heading is , I got this car to drive while I'm building another one but I have two cross country trips planned soon and with the old 3 speed the car is screaming at 85 mpg. The car is mint so I don't mind putting some money in it and in my area volvo parts ( like low mileage trannys) are cheap and easy to find. It's not a sports car so I figured why not leave it auto so I can text and sip my Starbucks like everyone else ��

Well, the AW70/71/72 will all be better than what you have since they have overdrive. Just a standard aw70 or aw71 would be fine for your application, and you can probably find one cheap. I'd give you a free aw70 if you lived near me.
 
Well, the AW70/71/72 will all be better than what you have since they have overdrive. Just a standard aw70 or aw71 would be fine for your application, and you can probably find one cheap. I'd give you a free aw70 if you lived near me.

I'm in Tucson... would gladly drive up 😁
 
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