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122 transmission options

spock345

Well-known member
Joined
Nov 3, 2016
Location
Livermore, CA
I have now finished the motor swap in my 122 and am about done with going through the ignition system.

I am now thinking about the transmission. Mostly I would like to put something with an overdrive in the car. 3500 rpm at 65 mph is a bit much for any distance on the highway. Luckily the car originally had an automatic so it has a larger transmission tunnel which makes fitting something non-original in there a bit easier.

An M41 would be the easiest option but I haven't had much luck finding a complete one. Is there any other transmission that would swap into a 122 without welding in a tunnel from a 140 or 240? I looked at the S10 T5 but it seems like the shifter is too far back by about 5 inches.

I am rather happy with my motor as is and can't see myself doing anything other than raising the compression ratio a bit. So it wouldn't have to handle a bunch of power.

Does anyone make T5 adapters for a B20 other than John Parker (I've read the warnings)?

I'd like to figure out a plan so I can keep an eye on classifieds and junkyards for a suitable transmission.
 
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And relocating the hole for the shifter.

If I need to relocate the shifter by welding in a new top for the tunnel I don't consider it too hard of a task. Just more of a headache.

At this point I am weighing the pros and cons of the T5 parts availability versus the easier bolt in M41.
 
If you do the T5 path, make sure you get a T5 with the correct set of ratios for the B20 and your differential. The spreads on some of the T5 boxes work well with big V8s, not so well with less big B20s. The T9 is probably a better fit for the Amazon in terms of ratios and size; but, rare as hen's teeth on this side of the Atlantic. Tinus Tuning makes an adapter plate for the T9 on to a B20.

https://www.tinustuning.nl/1-onderdelen-aandrijving.html

TT also modifies bell housings to fit an M45/M46 behind a B20; but, you need to provide the donor bell housings. The M46 may be slightly more available than the M41; but, the shifter is coming up in the wrong location requiring modification of the tunnel (as will a T9). If HiPerf can supply you with a refreshed M41 I would go with that option to minimize hassle / fiddling with things and maximize the driving time.
 
an m41 runs 750 to 1k or more fyi. That might be the issue?
a t5 will be the same or more with parts / adapter plate etc.

Depending on what the T5 costs (pick n pull vs wrecking yard vs reman unit) they should be about the same.

I've located an M41 with a D type nearby. I'll probably go check that out. I am just trying to figure out if that will blow up behind a mild B20.

So it is a trade off between bolt in but difficult to find parts and easy to find parts but a bit of cutting and welding. Also the vibration issued I've read about with regards to the T5.
 
The early M41s with a D overdrive when in good condition can take spirited driving.

However, when Volvo went to the B20, they also beefed up the M41 with a larger rear bearing and upgraded to the J overdrive which is stronger than a D.

In either case, avoid slam shifting into 2nd gear. Back in the day, we used to have a collection of cluster gears from M40s and M41s with 2nd gear sheared off whilst drag racing.

Then we discovered the M400/M410 which is reportedly strong enough for upto 400 hp and we've never broken 1 of those and those are even harder to find.
 
The early M41s with a D overdrive when in good condition can take spirited driving.

However, when Volvo went to the B20, they also beefed up the M41 with a larger rear bearing and upgraded to the J overdrive which is stronger than a D.

In either case, avoid slam shifting into 2nd gear. Back in the day, we used to have a collection of cluster gears from M40s and M41s with 2nd gear sheared off whilst drag racing.

Then we discovered the M400/M410 which is reportedly strong enough for upto 400 hp and we've never broken 1 of those and those are even harder to find.

I've avoided slamming any volvo transmission into 2nd. Usually because the synchros are bad enough to either take a while or need double clutching for a smooth shift.
 
Then we discovered the M400/M410 which is reportedly strong enough for upto 400 hp and we've never broken 1 of those and those are even harder to find.

planetman is certainly correct about this. I'm rebuilding two of them right now with some of his help with parts. The rest I'm getting from Sweden.

Everything inside of them is about 25% larger than what is in a M40/41. See comparison photos @ https://www.facebook.com/groups/232999844689051/permalink/406772987311735
 
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