Swapping for 951 or 968 transmissions?

[mdisanto]

I have been thinking about swapping a 951 or 968 (6 speed) transmission into my 89 944S2. Some guys have told me that the difference is enormous. I am looking for some extra opinions on this. Good idea or not? Can anybody help with the correct gear ratios for the 951 transmissions so I can make a comparison with mine? The info I have is confusing. Thanks in advance.

[fletch944t]

Hi Michael,

I don't think you'd be happy with the 951 tranny in an S2. The gearing is a bit taller and it would give you a little more top end capability but, I don't think you'd be happy with the response in the lower gears. It's for that very reason that you'll frequently see 951 owners install S2 or other N/A 944 trannies into their cars, especially if they're going to do a lot of auto-crossing which requires a lot of work in the lower gears. The 951 tranny would, however, bolt directly into your car.

The 968 tranny would be a better choice than the 951 tranny with regards to gearing. However, there are a number of logistics issues to deal with in regards to installation. It is possible to get by with your stock drive shafts. However, you're much better off using the 968 shafts as they are the correct length. You can also get by with the stock shift linkage but, the 968 linkage is much smoother with less slop. However, the biggest issue is with speedometer signal development. The 944 trannies (1985.5 and newer) have a Hall effect sensor mounted in the tranny for speedometer signal development. However, the 968 tranny doesn't have this and doesn't have provision for installing one. So, you have to come up with some other method of speedometer signal development. Typically, this has been done by installing a bracket on the side of the tranny to position a hall effect sensor near the CV joint and then mount a strip of metal on the CV joint. As the metal passes the sensor, it induces a signal which can be used for speedometer signal. However, you have to send that signal to the speedometer via an electronic ratio adapter to get the correct number of "pulses per mile" going to the speedometer.

The 968s pick up the speedometer signal by using the output from one of the front wheel ABS sensors. I don't know of anyone, yet, who has tried to tap into the ABS sensor on a 944 to pick up the speedometer signal.

I will soon (hopefully soon) be installing a 968 six speed in my '86 944 Turbo. I recently installed a set of Big Red brakes using M030 spindles and hubs (ABS). Since I have a spindle with an ABS sensor mounting point but, don't have ABS on my car, I'm going to try mounting an ABS sensor in the spindle and use the output strictly for speedometer input (via an electronic ratio adapter). I'll let you know how it turns out.

Regards,
Clark

[overkill]

What does a used 951 or N/s tranny usually run?

[mdisanto]

Clark, thanks very much for the details. Very much appreciated.

[fletch944t]

Originally posted by overkill
What does a used 951 or N/s tranny usually run?

Depends on where you get the trans from. I've seen used N/A and 951 trannys go on Ebay for as low as $700-1000. From a recycler or private party sell off Ebay $1000-1500 is fairly common. Also, add about $500 for LSD.

There's a pretty high demand for 968 trannys. I've seen them go for $2000-3000.

[Etnier]

Here's something I just posted in a related thread-

FWIW I have been driving a 93 968 for about 10 months now, and drove 944's for years before that. I fitted a 951 trans into my last 944, an 86' NA, after the old trans got noisy. It was great! Came with an LSD, as they all did. Tight smooth responsive shifting.

By comparison, the 968 6-speed is much harder to work with in day-day driving- it's very easy to skip gears or find oneself in reverse when going for first. I think you'd save a lot of money, gain an LSD and have a more responsive transmission if you went the 951 route.

[fletch944t]

Originally posted by Etnier
Here's something I just posted in a related thread-

FWIW I have been driving a 93 968 for about 10 months now, and drove 944's for years before that. I fitted a 951 trans into my last 944, an 86' NA, after the old trans got noisy. It was great! Came with an LSD, as they all did. Tight smooth responsive shifting.

By comparison, the 968 6-speed is much harder to work with in day-day driving- it's very easy to skip gears or find oneself in reverse when going for first. I think you'd save a lot of money, gain an LSD and have a more responsive transmission if you went the 951 route.

Sorry but, that is incorrect. The LSD was only standard equipment on Turbo S models. It was optional on all other 944 Turbos. In fact, it's a little difficult to find LSD on an '86 or '87 944 Turbo. Mine has a stock tranny which is definitely NOT LSD.

Here's a summary of 944 Turbo tranny codes:

16R - 5P, with oil cooler / no LSD (standard on '86, optional '87 on)
16R - 5R, with oil cooler and LSD (optional '85 on) i.e. Euro models in '85
16S - UY, no oil cooler / no LSD (standard '87 on)
16S - 9U, no oil cooler but with LSD, (optional '87 on)


Also, I know several people who have put turbo trannys in normally aspirated cars, hated them, and ended up going back to a normally aspirated tranny.

Regards,
Clark

[still2slow]

Revisiting this; does anyone know of a solution regarding the speedometer system conversion?

Many thanks!

[mikepellegrini]

I know Seattle951 put a 968 transaxle in his 86 951. If Clark's forums ever get back up, you might ask him.

[thekidd]

ive thought ive seen NA go for around $300 right here om PP. Check out the used parts section, probally your best bet, were (hopefully) honest.