That would be really cool if you can take it on Paul. If Bill (the guy who did these conversions before) can provide any assitance just PM him on outerlimits and I'm sure he will be happy to help.PTSchram said:I have idle machine time...
My machinist friend is coming over to the shop today, we were gonna discuss diesel conversions and a bulletproof axle arrangement (those of you who know of what I'm talking, keep your fawkin' mouth's shut, Shopgrrl is almost ready to let me spend the dollars for the bare case), but I strongly suspect this may be of interest as well.
Time to go pull the T-case out of the crashed Cherokee in the lot of the body shop downstairs...
daddylonglegs said:Hi gents, Bill here. i will try to give you a brief rundown on what is involved in making up a crawler gearbox that fits to the pto aperture on Landrover series tranfercases and 4 speed LT95 tranfercases also.
The parts you will need are, an old Fairey overdrive to suit your particular transfer. This must have an input shaft and adaptor gear that is in good condition in the male and female spline area. You will also need to source the bolt on two speed high low range planetary gearbox from a Borg Warner Quadratrac transfercase as used on automatic Jeep wagoneers, Cherokees, CJ7's etc from circa 1980's If you plan on stealing one, these vehicles can be identified by having a rear diff that is offset to the right whereas non Quadratrac models have a centred rear diff. The only partts of the old overdrive you will use are, part of the gear case from the flange forward.
The adaptor gear, the input shaft and the cylindrical output gear. and some needle thrust and roller bearings.
the fairey input shaft is cut and resplined to engage with the female spline of the Quadratrac input gear. The Fairey cylindrical output gear is modified by grinding the teeth off the small helical gear at one end, and welding on the course splined dog from the old Quadratrac out put gear.
An aluminium adapter and blanking plate will need to be machined up to bolt the planetary unit to the Landy pto aperture. I have only performed this conversion twice. on a series 2a tranfercase and an Lt95 and I worked out the dimensions as I went along, so unfortunately i didn't make drawings. They have proven to be very strong with hard use over the years. I had to replace the roller bearing with a bronze bush on the adaptor gear due to brinelling as the planetary unit spends most of its life in high range. This brinelling also occurs on standard Fairey overdrives if overdrive is not engaged regularly. This conversion will not suit lt95's with the large handbrake assembly. you must adapt the smaller handbrake from a series i,2 or 3 or the early Rangerover 4spd. It could possibly also be adapted to the later Lt230 transfer case but as there are no dead overdrives around for these it would be more complicated and expensive.
The low range ratio in the planetary unit is 2.57:1 when this is combined with the LT95 gearbox and 3.54 diffs it yeilds an overall ratio in low low 1st gear of around 127:1 . Standard low 1st is around 48:1.
My own series 2a LandRover fitted with a D series Ford truck gearbox, suffix b tranfercase, crawlerbox, 3.54:1 diffs and 1:56:1 hub reduction in the portals yields an overall ratio in deep reduction 1st gear of 278:1.
Most people would think this ratio is unusable, but with lockers, good tyres, lots of ground clearance and gobs of axle articulation I have used this ratio to good effect on many occaisions.
Because the company that I was involved with "Off Road Rover" is no more. and I no longer possess the machining facilities that I once had, my assistance with this conversion unfortunately is limited to advice.
I have seen a similar pto mounted crawler box on a landcruiser transfercase in the showroom of Marks 4WD adaptors. It apears to be a coventional Mainshaft Layshaft (non planetary}design. They do not appear to like Rovers too much over there, so I am not sure how easy it would be to persuade them to adapt the crawler for rovers.
Incidently, I had heard that Ashcrofts crawler unit was withdrawn from the market because they were having too many warranty claims, not because of low sales volume. Ashcroft is not a volume oufit and one or two units per month would probably have been enough for them.
They're not done yet! :flipoff2: (I do have the stock to make them with though, man steel has gotten expensive)ISUZUROVER said:Of course at the rate you made those tools for pendy this could take years :flipoff2:
I'll come and help out as long as I can borrow a landie to wheel moab when camp is overPTSchram said:Anybody want to come to Indiana for camp? Won't be nearly as exciting as Pendy, I'm married and she works at the shop :grinpimp:
I didn't remember the name, but have vague recollections of the beginning of the journey. Most vivid was your letting me drive :flipoff2: . We go out of our way looking for Fords here in the US now-very few, if any on public roads, many in the woods where we wheel most often.tony cordell said:PS Paul do you remember Putham Lane? the first I took you down on Exmoor?
Well we have moved to the national park now and that very lane destoyed a CV/Stub axle bearings and damaged the hub/Maxi Drive drive member on Sunday :flipoff2:
2.57 times what is applied with it not engaged. You would need to avoid hitting the go pedal in 1st/low/low as your axles would snap like twigs.PTSchram said:How much torque is applied to the transfer case when the underdrive is engaged?
Paul, you need more gear tooth data than that if you want a replacement.PTSchram said:OK fellas. The wheel is turning (with apologies ot the grateful dead).
Does anybody know the specs on the main input gear of the LT-230? I believe this is the one that will require the mods for the underdrive. I need ID, OD and pitch of the teeth. my machinist buddy told me "It is not feasible for you to make the gears", but he feels confident an off-the-shelf part is available that will work for our purposes. It helps to have friends who are machinery builders.
Secondly, tell me why one couldn't extend the adapter to the point where interference with the brake drum would not be a problem? I can see some minor issues, but no deal breakers and the advantage of retaining the original brake drum is obvious.
Lastly, what transfer cases are best suited to this purpose? Year/Make/Model? Are there any that will not work?
PTSchram said:Secondly, tell me why one couldn't extend the adapter to the point where interference with the brake drum would not be a problem? I can see some minor issues, but no deal breakers and the advantage of retaining the original brake drum is obvious.
daddylonglegs said:For anyone that is interested, I have had a look under a Defender and Discovery and have determined that I cannot space the crawlerbox back far enough to clear the large handbrake assembly. there is a crossmember preventing this on Defender and rear passenger footwells on Disco's. It is either a series handbrake conversion or nothing for the Quadratrac.
daddylonglegs said:Rangey footwells are in the way too I think.
I don' know why the resistance to fitting Series 2/3 Handbrake ! To make an omelet you have to break eggs.
Is that the effective torque multiplication to the axles, or to the case of the underdrive?red90rover said:2.57 times what is applied with it not engaged. You would need to avoid hitting the go pedal in 1st/low/low as your axles would snap like twigs.
1: If I build one of these for myself, it will most likley go into a series/rangie hybrid and floor clearance isn't expected to be an issue :flipoff2:ISUZUROVER said:
PTSchram said:1: If I build one of these for myself, it will most likley go into a series/rangie hybrid and floor clearance isn't expected to be an issue :flipoff2:
2: If I understand correctly, are we only using the planetary reduction unit from the quadratrac? I wonder what other US mfgrs have a physically smaller unit that will fit into Discos, etc perhaps without modifiying the floopan, nor requiring replacement of the brake drum (insert chin-scratch smilie flipoff here)
From the outer limits discussion, it appears as though their biggest concern is having the adapter flange made. Curiously, this seems to me to be the easy part Expensive for the stock, and then, to waste most of it in the form of chips on the shop floor-maybe a casting would be a better way to go.
Is there any torque applied to the case of the underdrive? Seems as htough there wouldn't as none of the gears are stationary and working against the case.
Time to get to the shop and call my machinst friend now that I have a lot more info.
Of course, this is yet another case of my having let something of value go to the trash before I knew I needed it (Slade's blowed up Fairey).
I believe this is the only t. case built this way, period.. Only choice.PTSchram said:2: If I understand correctly, are we only using the planetary reduction unit from the quadratrac? I wonder what other US mfgrs have a physically smaller unit that will fit into Discos, etc perhaps without modifiying the floopan, nor requiring replacement of the brake drum (insert chin-scratch smilie flipoff here)
No, the adapter flange is simple. The hard part is making the concentric input shaft / output shaft and gear arrangement.PTSchram said:From the outer limits discussion, it appears as though their biggest concern is having the adapter flange made. Curiously, this seems to me to be the easy part Expensive for the stock, and then, to waste most of it in the form of chips on the shop floor-maybe a casting would be a better way to go.
daddylonglegs said:I have at last found the time to remove the crawler box from my series 2A
I will take some photos with a digital camera during the week and post them, but first I will gather some standard Fairey overdrive parts to show how I have altered them for the conversion.
For the LT230, it has occurred to me that some parts from a second Quadratrac could possibly be modified to make the spud shaft to extend the R380 mainshaft to reach into the reduction unit. If you look at the exploded view of the Quadratrac that Red90 posted on page 1, the parts described as ''Sungear'' and ''Shaft extension'' are what I am refering to. I do not know if these parts are even available as spares from BorgWaner, but if they were available cheaply the spudshaft could be made by machining the helical gear off the Sungear, pressing the shaft extension halfway into the splined sleeve and pressing the sleeve onto the R380 mainshaft. I do not have a spare reduction unit so I can't be certain that this idea would work but it does look feasible.