D type vs J type Laycock Overdrive - Volvo

[@olewurtz7625]

Just an FYI on the capability of these overdrive units. I installed a 4 speed with J type overdrive in my Jaguar E-type. I got a refurbished strengthened o/d unit from the company in Sheffield, England. No issues with the roughly 270hp from the V12. It would engage with a snap without slipping, but I’ve always eased the accelerator when engaging and used the clutch when disengaging the o/d.

[@fallofmanbrand]

amazing video

[@patrickadams8941]

I found a J type O/D unit in an 86 GMC C3500 1 ton truck. How much hp and torque can these units handle?

[@Prowbar]

Interesting... Was it mounted on the back of the transmission? Or remotely mounted in the driveline?

[@anthonydepueable]

I think that that I need to rebuild my j type overdrive on my m46 manual transmission. Just did a trans swap on volvo 245. Gearbox feels great all new clutch components. Used all sensors from original trans. They all worked prior. When install was complete and took for test drive everything was great but once od was engaged made a bang and clunk noise followed up by some cluttering sounds. Immediately I took out of overdrive. All electrical seems in good order. Solenoid heats up with switch on. Lights work with no flickering. Havent torn into the overdrive yet. It would be my first. Could use some help understanding the problem before I pull the transmission out of car again. Swap took me about a week. Not much information out there on this od systems that I have found. I did read up on your link you shared. Any suggestions or recommendations to help with my situation?

[@cocomiel3538]

Hello how are you? My type j solenoid broke and I can't find it in my country. Is there any other car that uses a similar part? Thanks a lot!

[@bernardwarr4187]

Triumph cars too!

[@fallofmanbrand]

nice video bro

[@radiohorebproductora]

hola david, hablas español ?, gracias

[@Frundsbergp10]

I like to build this unit to a prewar car. Anybody knows that how is the ratio? 4th gear I think 1:1 and with OD????

[@DavidBello]

0.797:1 is reduction on the J type, 0.756:1 on the D type

[@Frundsbergp10]

@@DavidBello Thank you! So the J type is 21% and the D type is 25% longer than 1:1?

[@Cwazywazy140]

I put my 240 in reverse with the j type engaged once, I let off the clutch and nothing happened. I just sat there, no noises or anything.

[@DavidBello]

My understanding is if you start driving that’s when the input shaft on the OD starts pumping and building pressure and then the axle spinning in the opposite direction is fighting the unidirectional clutch, stressing it and potentially breaking it.

[@Cocobrain26]

I thought the overdrive unit takes ATF?

[@DavidBello]

It can. They work with a variety of fluids. I went with a non-detergent SAE 30 to assist in keeping the debris and grime off the vital components as recommended by factory specs.

[@conceptalfa]

👍 👍 👍!!!

[@justinbrian6992]

Modified m40 to an m41? How did you do that? You did the impossible, you could make a whole video just on that

[@DavidBello]

Just change over the mainshaft to the longer style that the overdrive can bolt into. I do have a video coming for the M41 gearbox and OD reseal