3.5 liter with automatic gearbox

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Henrik

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I am restoring my 2800CS automatic (from scratch). I was originally planning to overhaul the engine, but the costs of this will match and even exceed the costs of installing a used 3.5 liter. Since most 3.5 liters comes with an automatic gearbox I wonder if it will fit my car?

I have looked in the old Forum files, but I have only been able to find manual gearbox topics.
 
I seem to recall a thread on the old board where they say a 4HP22 will fit with a little cajoling. It would need to be one of the early ones, however, since the later ones have electronic, rather than mechanical, control systems.
 
Alternately, you could just use the original 3hp22 trans your car has now, or if yours is weak, pick up a good used one for a fair price. It will be fine behind a 3.5.
 
That sounds like my melody!
The job would be much easier (and cheaper) if my old automatic can work properly with a 3.5L (up to 1988???).
I don't know if the gearbox works at all, but now I can go on without buying the whole package (motor-gearbox- new pedals etc.etc)
 
I know the 4HP22 is a pretty stout trans, but what about the 3HP22? Can it handle the additional torque?

An advantage of the 4HP22 over the 3HP22 is the 4HP22 would give you an overdrive gear, improving your mileage, but it would take some tweaking, certainly more than the 3HP22.
 
3hp22 is stout, a stock or even mildly built 3.5 will be no problem.

4HP22 is good too, and as mentioned, has a lock-up TC, but -- be sure the "A" clutch pack has been upgraded to improved spec. Early models of this trans were infamous for failing after the owner went to emissions testing and the car was revved up in neutral, which would starve the A pack of fluid and cook it.

Land Rover used the 4HP22 for years in the Range Rover, Discovery and even some Defenders, behind the BOP/Rover V8. They're well regarded for strength and reliability -- unlike many of the parts on those trucks! :p My Range Rover Classic is approaching 150k with no transmission issues. (insert "kiss of death" sound...)
 
Tony,
Rangies with Autoboxes seem to last forever, much better than the manual ones.. Mate has oner with +375,000 miles and still on the same automatic gearbox
Mind you he does change the oil and clean out the filters?? (I don't know much about auto boxes) every 25,000 miles
Malc
 
speaking of automatics I wonder if there are 4 speed automatics that can replace early 3 speads?

Just being hopefull, Enrique
 
Thank you for all information!

I will start looking for a 3,5 engine, and if the deal includes a ZF4HP22 with mechanical control system, I will install it. If not, I go for the old ZF3HP22.
I guess a gearbox workshop can test it before mounting it in the CS.

Henrik
 
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