|
The various AW automatic transmissions that Volvo used were designed to match the different powertrain outputs of the various B23OF, B230FT and B234F engines.
The gearing is very different in the AW72L trans used with the DOHC 16-valve B234F so on a B230F it will behave quite differently compared to your original AW70L trans. That engines breathes differently, with the torque curve significantly skewed to the right compared to the the similar horsepower of the B230FT turbo, so they re-geared the AW70L to better suit shifting under normal acceleration. I still found the AW72 gearing unsatisfactory for the way I drive: The 1st gear ratio was a bit too low (horrid on ice or in snow, also too easy to spin your wheels starting from a stop on slick pavement), the 1st to 2nd gear shift point was similarly low, making for too large a gap from 2nd to 3rd (which is the 1:1 gear in all the AW trans). They also modified the rear output ratio to better suit overall performance and fuel economy. The AW72L bell housing is also different, with the block mounting offset to match the different mounting angle of the DOHC engine.
The gear ratios and lock up torque converter speeds for the later 700/900 years with lockup torque converter appear to be as follows:
AW70L (B230F). (1st) 2.45:1, (2nd) 1.45:1, (3rd) 1:1, (4th/OD) .69:1
..... output ratio 4.10, lockup ~75 km/h =~53 mph (ratio 4.10, lockup ~77 km/h =~48 mph for Europe)
AW71L (B230FT) (1st) 2.45:1, (2nd) 1.45:1, (3rd) 1:1, (4th/OD) .69:1
.....output ratio 3.73, lockup ~77[*] km/h =~48 mph (ratio 3.91, lockup ~84 km/h =~52 mph for B230K in Europe)
AW72L (B234FD) (1st) 2.83:1, (2nd) 1.49:1, (3rd) 1:1, (4th/OD) .73:1
.....output ratio 4.10, lockup ~85 km/hr =~53 mph
Ref. Volvo Service Manual (TP31642) AW70/AW71/AW72
The gear ratios for the AW trans without lockup torque can be found in that manual.
(...If that website is blocked then try using a search engine to get access to the PDF file without the error...)
[*] suspected typo in manual, says locks up at ~97 km/h (no way, I have both a later AW70L and AW71L and they have similar lockup speeds).
I just learned something from Randy. I didn't realize the kickdown cable used with the DOHC 16-valve B234F is a bit shorter than that used with the B230F/B230FT engines. That's because the cable bracket on the intake manifold is located slightly further back. An AW70/71 cable should be used with an AW72L trans when mounted to an SOHC B230.
The longer cable may also fit the B234F, but I'm not sure how much more of a bend it makes that might hasten the wear of the lining inside the cable, or better yet for a new cable would be to pull out the cable and cut the sheathing shorter before re-inserting the cable and clamping on the new ferrel. FYI, when clamping the new ferrel, best to clamp it after adjusting the kickdown so that you leave a bit of a space from the bracket to accommodate later adjustment. The ferrel is only there for crude adjustment and to prevent the cable from retracting down into the sheath.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
|
