Auto gearboxes

[Steve28]

Is the auto gearboxes the same in the sprint and 1500's ?

[Jon Tilson]

No....similar internals but externally quite different.

Jonners

[Toledo Man]

There's also differences between the Sprint and 1850 autoboxes as well.

[Steve28]

So will not interchange then.

[Steve28]

There's also differences between the Sprint and 1850 autoboxes as well.

whats the differences between them.

[MIG Wielder]

Swapping parts from one auto box to another is in the advanced class of Dolomite maintenance. The big problem will be finding the parts. It is going to be far easier to swap the box with one from a known good breaker.
But to answer you question, and with a parts book to hand, there are 6 variants of converter housing.

1500 early / late
1850 early / late
Sprint early /late.

Then when you get to the torque converter the 1500 is 520009.
Sprint and 1850 are 601000.

None of these parts have known suppliers.
The main casing is vaguely the same but the dipsticks and tubes are different as is the kickdown cable.
The sump is the same.
The parking mechanism differs between 1500 / 1850 / Sprint but the part numbers given are vague.
Front pump and servo look the same but the brake band is different on the Sprint
Rear servo front clutch look the same.
Rear clutch is very different between the models as is the governor.
The big killer is the upper valve body which probably differ in the castings as the internal parts look the same
Lower valve body is the same.
In the rear housing the speedo drive differs.
Then the gear lever operating rod is different.
Nope. I'd go for 2nd hand from a breaker with all the accessories..
HTH.
Tony.

[Steve28]

Thanks for the thorough explanation tony, i have a sprint auto box but i will never fit it into my manual sprint,
but ive also got a 1500tc auto and just wondered if it was worth hanging onto if it was the same, just incase.

[gmsclassics]

Interesting as when I converted my Mimosa Sprint to auto, it was a unit from an 1850 that I used. I have only ever heard of one genuine auto Sprint in NZ, in pieces with the owner heading to the UK to work. So a Sprint autobox just wasn't an option.

The only obvious difference I found was the lack of a transmission cooler on the 1850, so I changed the plumbing and fitted and aftermarket one in front of the radiator. I have a feeling it still overheats in slow traffic on a hot summers day. There was discussion then on this forum and even 'harvey' could not be sure what the differences were, but did think the number of plates in the clutch could be different (or that's what I think he said). I must admit that it appears to function relatively smoothly and efficiently, bearing in mind it is only 3 speed, not 8 speed like in my XF! It seems to work well with the torque delivery of the Sprint engine as it spends almost all its time in top. I've covered at least 5000km without issue so far, but have a spare under the bench just in case!

Given these BW65 units have been fitted to Jags and Rover V8s, the internal options must be quite extensive. I did wonder about looking for a unit from a Jag to fit, but wasn't sure about the compatibility of the torque converter.

Any information on how to identify early / late or 1850 / Sprint and what the precise differences are would be much appreciated if anyone knows.

Geoff

[harvey]

Interesting as when I converted my Mimosa Sprint to auto, it was a unit from an 1850
The only obvious difference I found was the lack of a transmission cooler on the 1850, so I changed the plumbing and fitted and aftermarket one in front of the radiator. There was discussion then on this forum and even 'harvey' could not be sure what the differences were, but did think the number of plates in the clutch could be different (or that's what I think he said).

I did say that, but it was a guess as I don't have written proof to back it up, and I wouldn't dismantle the Dolomite 1850
autobox I've got here just to find out. (Even if I did it could have been built up with more plates than standard at some time). BW did like to make economies wherever possible though. Adding a cooler will go a long way to help it.

Given these BW65 units have been fitted to Jags and Rover V8s, the internal options must be quite extensive. I did wonder about looking for a unit from a Jag to fit, but wasn't sure about the compatibility of the torque converter.

The Bw65 fitted to Jag, Rover & BMW had larger servos, and hence a different main casing, other makes got the smaller ones, all the other internals would be pretty much the same apart from the number of clutch plates. The smaller converter would fit OK to the larger (better specced) boxes, and if you were really keen you could uprate a JAG/Rover/BMW box by fitting a BW66 sump and filter spacer to add a bit to the fluid capacity. You couldn't use the other BW66 upgrades with the smaller converter though, unless you cut two converters in half, swapped over a few bits, and welded them back together again.....

[Magenta Auto Sprint]

I have stripped a few Dolomite auto boxes now, I think the number of clutch plates may be the same but the spring pressure may be differant, the valve blocks have the same number 6005.

The parts catologe quotes three different white metal bearing sizes in the extension housing, so the shaft diameter is differant from Triumphs to Jags etc.