Need an overdrive for my 1986 Ford 6.9 diesel

[My87Landmark]

Can't drive this anymore at 2800rpm's doing 58mph. A gear vendor is probably the easiest. An E4OD rebuilt to handle the diesel with an aftermarket controller is an option. I've heard a drop of 500rpm's with the GV & possibly more with the E4OD. I am looking for all the feedback I can get. Thank You all

 

[IDIBRONCO]

If you go the Gear Vendors route, you might also want to think about a low stall torque convertor too. That involves dropping the transmission, but any bit of RPM drop helps. Overall, I would be happier with a E4OD since they have a lock up convertor.

 

[Tgould]

My e4od and 3.73 gears gets me 2100 at 70mph. Gv might get you more, I dont remember the ratios of either. A lock up convertor will make a big difference and wouldn't build as much heat as the C6 and Gv.

 

[u2slow]

If I had kept my E350, the plan was to ZF5 swap it. I did not like the E4OD.

 

[ironworker40]

You would be way better off with a E4OD, better yet with a ZF. The gear vendor on paper rpm drop will not be what you get because the c-6 converter is loose as hell. I installed one in 1988 on my 1987 f250. Been there done that. What gears do you have in the rear? Do you need that low of a gear for towing? If not a gear change would be an idea also.

 

[franklin2]

Can't drive this anymore at 2800rpm's doing 58mph. A gear vendor is probably the easiest. An E4OD rebuilt to handle the diesel with an aftermarket controller is an option. I've heard a drop of 500rpm's with the GV & possibly more with the E4OD. I am looking for all the feedback I can get. Thank You all

Figure the cost to go the two different routes, the E4OD versus the gear vendor. I think you will find they are close to the same price, but the E4OD fits better and will give you a little bit better mileage with the lock-up convertor.

 

[IDIBRONCO]

Figure the cost to go the two different routes, the E4OD versus the gear vendor. I think you will find they are close to the same price, but the E4OD fits better and will give you a little bit better mileage with the lock-up convertor.

The down side is that either way, you may have to shorten your driveshaft. I KNOW that you'll have to with the GV, but I can't say for a fact without measuring the E4OD. I can measure a 460 C6 and it should be the same length as one for a IDI, but I don't have a 4X2 E4OD to measure.

 

[lotzagoodstuff]

+1 for lockup converter/E4OD over the GV. The E4OD is not the best automatic transmission ever made, but you can build one to take anything your IDI will throw at it.

 

[KansasIDI]

The down side is that either way, you may have to shorten your driveshaft. I KNOW that you'll have to with the GV, but I can't say for a fact without measuring the E4OD. I can measure a 460 C6 and it should be the same length as one for a IDI, but I don't have a 4X2 E4OD to measure

C6, T19, and ZF5 are all equal in length

E4OD is longer

 

[Nero]

Aren't gear vendor parts/kits hard to get for our era of trucks as well?

 

[IDIBRONCO]

C6, T19, and ZF5 are all equal in length

E4OD is longer

I believe that a GV on the back of a C6 makes it longer too.

 

[Tgould]

Going from c6 to E4OD i had to shorten my driveshaft. Though I dont know why that is the hanging point for so many swaps. And the only part of a gear vendor that is specific to anything is the trans adapter. The rest is universal. And will add 16" no matter what you hook it to.

 

[DirtyWood]

The E4OD isn't half as bad as people make it out to be. Yes the early ones sucked and failed prematurely, but with proper cooling and fluid changes they can be quite reliable. And since you're swapping everything in it gives you the chance to make sure the wiring and all electrical connections are done right.

 

[KansasIDI]

I believe that a GV on the back of a C6 makes it longer too.

Touché

 

[IDIBRONCO]

I've always preferred the E4OD myself, but I don't have much long term experience with one.