Swapping out overdrive 4 speed for a 5 speed box

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Maidstonerob

Swapping out overdrive 4 speed for a 5 speed box

#1 Post by Maidstonerob »

I have a problem with the overdrive on my 1850hl.
Problem 1 it doesn't work.
Problem 2 I am utterly clueless in all things overdrive.
Is there a 5 speed box that will mate with the 1850 engine and if so are there lots of mods required?
dailysprinter
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Re: Swapping out overdrive 4 speed for a 5 speed box

#2 Post by dailysprinter »

Check oil level first. I dont reckon it will be too easy to find abox to fit without loads of modd
plus its nice been able to change gear by flicking a switch!
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Maidstonerob

Re: Swapping out overdrive 4 speed for a 5 speed box

#3 Post by Maidstonerob »

Thanks Is there separate oil for the overdrive unit or does it simply share oil with the gearbox?
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sprint95m
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Yes.....

#4 Post by sprint95m »

Maidstonerob wrote:Is there a 5 speed box that will mate with the 1850 engine and if so are there lots of mods required?
Ford Sierra type 9.
I have done this to an early 1850.
There are some modifications required inc. shortening the gearbox remote, welding a Ford prop front section
to a Dolomite propshaft, welding a Sierra gear lever bottom section to a Dolomite gear stick.
You are looking c. £300 to 400 depending on how much you can do yourself/how secondhand parts you can use.



As you already have an o/d 'box I suggest you persevere with it.....
the oil is shared between box and o/d.




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Re: Swapping out overdrive 4 speed for a 5 speed box

#5 Post by cliftyhanger »

Most od problems are electrical. With the engine off, but ignition on, gearstick in 3 or 4 can you hear a click from the solenoid when you switch the od in/out?
If may be a faint click, so listen carefully or get under the car.
Report back......

Keeping the od box will save you a fair few quid, good type 9 boxes fetch £200 plus these days. Add a prop, adapter and so on the £600 figure is marginal.
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Jon Tilson
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Re: Swapping out overdrive 4 speed for a 5 speed box

#6 Post by Jon Tilson »

As the boys all say most o-d faults are electrical.

Not hard to sort. The failure points are usually around the connectors and the stick loom. Also the inhibitor switch is another possible
cause of failure. You can start by popping the stick switch off and seeing if you get volts on one of the leads with the lever in 3rd and 4th.

If you don't start chasing it back. Also do the reverse lights work? That will tell you if the loom connector by the bell housing is supplying power.

Sorting yours out will be by far the cheapest way forward, even if the end game is an exchange overdrive unit which can be slid off the back in an 1850.


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Re: Swapping out overdrive 4 speed for a 5 speed box

#7 Post by Henk »

Here's a helpful image, OD fault finding:
http://www.sprintparts.com.au/display.c ... ng.jpg.htm

I have to admit, my last OD didn't work and I couldn't cure it. I replaced it with a revised one, had to send in the old one for exchange and asked the company about the problem. They replied that electrics and hydraulics were fine but that the pistons were too small for the cylinders... Probably excessive wear after 40 years.

Good luck, and maybe some helpful info in this thread:
viewtopic.php?f=4&t=25679
Maidstonerob

Re: Swapping out overdrive 4 speed for a 5 speed box

#8 Post by Maidstonerob »

Thanks all for the very useful suggestions. I wont have chance to have a crack at it for a week or so. Will follow whats been suggested and let you know how it goes. Nice to have a place to start so thanks again.
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Re: Swapping out overdrive 4 speed for a 5 speed box

#9 Post by whydidistartthis »

If your name has anything to do with your location. I may not be far from you?

Willing to lend a hand if it helps?

Martin
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Re: Swapping out overdrive 4 speed for a 5 speed box

#10 Post by wiggybum »

Late TR7s had a 5 speed LT77, so could be an easy and fairly cheap gearbox upgrade. Much stronger too, if a little heavy.

Otherwise, I would consider a sprint box - keeps it in the family using standard bits, the overdrive works like before and it is much stronger. the only tell tale sign will be the fact reverse has moved place on the gearknob!
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Re: Swapping out overdrive 4 speed for a 5 speed box

#11 Post by Jon Tilson »

True wiggy but the TR7 box has the slave cylinder in the same place as the 1850 rack.

Fitting a Sprint box needs the adaptor ring too as an FYI point.

Jonners
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Re: Swapping out overdrive 4 speed for a 5 speed box

#12 Post by xvivalve »

I was about to say thank goodness no one has suggested the LT77... :D

Not only the slave but also a chunk of the bellhousing too. As for cheap, they now fetch startling money in second hand unknown condition, they have an internal oil pump location meaning the car cannot be towed with rear wheels on the ground/prop connected and are heavier than a Sprint overdrive box which is heavier yet than an 1850 one. Then there is the need for a custom propshaft which on the Quicksprint added £300 to my problems!
Maidstonerob

Re: Swapping out overdrive 4 speed for a 5 speed box

#13 Post by Maidstonerob »

You guys won me over a while back lol seems to me anything but rectifying the OD is a.....non starter! Queue the tumbleweeds.
Maidstonerob

Re: Swapping out overdrive 4 speed for a 5 speed box

#14 Post by Maidstonerob »

Had a quick look today.

There is a clicking from the solenoid so not an electrical fault. Will check/replace the oil as there is clearly a leak that needs rectifying.
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Re: Swapping out overdrive 4 speed for a 5 speed box

#15 Post by oldred »

Sorry for hijacking this thread, but a quick question.

If I was to swap a late 1850 with slushbox to an 1850 with Sprint o/d box apart from axle and maybe prop and stuff like clutch pedal master/ slave o/d wiring harness...what else would I have to get?
Just that i have a Sprint o/d box kicking around and I just cannot be done with the slushy. I know there are people on here that love 1850 autos and thats great, but for me sitting on the mway at 60-65 cause the revs are sooo high makes it a pain. Got to say its great in town but then I don't do a lot of that.

Can anybody help here?

Phil.
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