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High Ratio Transfer Case Kit


5.0 average, based on 5 reviews

This product is currently out of stock

Product Information

For the Ser IIA & III we can offer a high ratio transfer case kit.

This kit was developed as a stronger alternative to the Series "overdrive." By using the High Ratio conversion the High range is raised by 31.8% (overdrive is 27.5%) whilst leaving Low range unchanged. This suits most users who like a higher gear for on road economy, retaining the stock low range for off road use.

Other advantages of this conversion, compared with fitting 3.54 diffs, are:- the speedo drive will not need re-calibrating, there is no loss of handbrake efficiency and most importantly there is no loss of strength.

Note you will need the suffix C, 36 tooth low gear, part number 532979,

Please note this kit cannot be used as well as an Overdrive but you can still use the rear PTO.

Sorry but we are not able to offer a fitting service on this kit,

The price for the kit is £360 exchange. There will also be an additional £75 core charge. To see an explanation of the core deposit please click here

This will be refunded on receipt of your old bare casing if this is returned to us.





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Product Code: HRTC

Installation Information » (Click to Expand Collapse)

To fit the kit, the old transfer case must be removed then change over the studs, dowels and subassemblies into the new case and build it up using the new gears and refit to vehicle. This kit will fit the IIA and III (big intermediate pin).

If the kit is to be fitted to the Series I or II you will need a new centre pin (large diameter), bearings and low range output gear. The part numbers for these additional parts are : 1 x 594195 pin, 1 x 532323 O ring, 1 x 521328 washe,r 1 x 532979 low gear (36teeth suffic C),  2 x 599869 bearing.

Technical Information / FAQ's » (Click to Expand Collapse)

The kit comprises:- 1 x Input gear 1 x Intermediate gear 1 x High range output gear 1 x Bare re-worked case 1 x Gasket kit


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Customer Reviews

Average Rating: 5

Game Changer

Having read many other reviews about Ashcroft's HRTC over the years I finally decided to invest and was lucky enough for one to be in stock at the time. I knew from the reviews that it should make a significant difference, but just wasn't prepared for just how much a difference it has produced! Much higher top speed and bottom end gear shifting at revs you would expect on a 'normal' vehicle. I run an 88" with a V6 and have had to completely remap how the whole power train performs due to the speeds it now reaches in each gear at max torque. It seems to have made 3rd a really long gear before shifting to 4th for optimum cruising. Expecting fuel consumption to improve once I've fully adjusted to the change, so just need to stop all the extra rattles now! (old box returned for the next lucky owner).

Chris Tucker :: Nov 25 2019, 21:31 PM

Best upgrade ever

This is one of the best upgrades I have ever done to my 109” Series 3. I live in Denmark and use the car a lot on motorways. The noise is now considerable lower and so is the consumption of diesel. I have fitted a 200 TDI minus T (200 TDI with no turbo) in the car. This engine has a little more power than the standard 2.25 diesel. I think the power is more or less the same as the petrol version. The 200 TDI is perhaps the most noisy engine you can fit in a Series. Before I fitted the High Ration transfer case It was impossible to speak together in the car if you were driving more than 80 km/h (50 mph). Now I can drive 100 km/t (60 mph) and stille have a conversation. Regarding the power and torque I don’t experience any major problems. The only minor problem I have experienced is when you drive 50 km/h the 4´gear is a little to high so I use the 3´gear. The 50 km/h is the maximum speed in most danish cities. Some years ago I fitted a brand new overdrive from a canadian producer on a 88". I found the overdrive very noisy (even it was brand new) and it was a little irritating shifting the gears. The extra gear stick was also an irritating when using the seat in the middle. I will definitely recommend the High Ratio transfer case compared to an overdrive.

Jesper Sander :: Sep 18 2019, 07:52 AM

High ratio Transfer kit in my Swb series Landrover

I had one of these kits fitted to my Series 3 landrover which has a 2a box in it. I can honestly say it is one of the best upgrades I have done. I used to have a overdrive which gave good gear selection flexibility but it was getting very warn and a new was massively expensive to purchase. I have a good condition 2.25 litre petrol engine which pulls well originally on 7.50x16 tyres. The kit was brilliant on long runs engine noise down and a more civilised experience. Around town was fine you have to get a bit used to the different gearing but its easily adaptable. I recently changed tyres to 225/75/16 and this has helped with acceleration and starting off in 1st gear on a hill. You will have to work out your preffered set up. Iam very impressed with the product and the service from Ashcrofts. I have been running this for about 6 years.

Chris Doel :: Dec 13 2015, 07:54 AM

Hi ratio transfercase

I have had an Ashcroft high ratio transfercase installed behind a fuel injected Mustang 5.0L V8 for 16 years now and it has help up without any issues. If you have a higher than stock HP engine that wants to see lower revs this is THE product to have.

TeriAnn Wakeman :: Feb 16 2014, 16:02 PM

High Ratio Transfer case

hi dave, just finished fitted the case. i have the two cases ready to send back and will be with you next week. i was having some trouble getting the dowels out so i left them in as you obviously have better equipment than i do. i didnt want to risk any damage by using poor removing tools. i have been out on a test run and i have to say, i am very impressed. i am yet to give it a long run but i have given it a good test and its frankly exceptional. i had been told many bad things about fitting it to a 109" due to the extra gearing of the bigger tyres. so i have a test in mind that will put it through its paces in a few different situations. a real world test, as it were. i will be writing it up for the forum i am on, simple stuff about how it works with the 109" gearing. if you would like i can send you a copy should you want it. its just something you can point people to if they ask about the gearing and if it will work, as i did. anyway, just wanted to say thanks and well done on a superb modification. cheers chris ________________________________________

Admin @ Ashcrofts :: Jan 23 2014, 14:27 PM

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