Converting 4-speed manual to 5-speed in 87 full size Bronco

[Ichblas]

I am wanting to convert my granny low 4-speed to a 5-speed. I have a 1987 stock Bronco and since that year only came with 4-speed manuals, will a 5 -speed from a later model fit?? Is there many modifications? Should I convert the clutch to a hydraulic?

 

[miesk5]

Yo Ichblas,
Welcome to our Bronco community!

ZF is the one to use!
See this ZF S5-42 swap into an 88 Bronco @ https://www.fullsizebronco.com/threads/88-zf-5-speed-conversion.

However, person claimed he had a C4 auto transmission in it, but he probably meant C6.
At least he has the ZF section covered!
The model number for the ZF transmission
(7003) is S5-42. This model number can be divided
into three parts.
First, “S” designates a synchronized transmission. Second, “5” designates the number of forward gears. Finally, “42” is the approximate maximum input torque capacity in tens of ft-lb. In this case 42 equals 420 ft-lb. input torque capacity.
The S5-42ZF transmission is available in both wide ratio and close ratio versions. The wide ratio version is available for all F-Series vehicles over 8500 lbs GVW, all engines (6007), except F-Super Duty Commercial Stripped Chassis equipped with a diesel engine.
The close ratio version is available only in F-Series vehicles with a 7.3L diesel engine and a GVW over 8500lbs. The ratios are as follows;


S5-42 Tips; "...There are three rubber plugs on top of the transmission that leak fluid only when the truck is in motion so when parked there will be no tell tail signs of a leak. You can replace the plugs yourself or take it to the dealer and have them check it for fluid lose and replace the faulty plugs but it's not cheap. Thing is, the seals are going to fail and if caught to lateas in my case cost you a bundle. Another set back for theback yard mechanic is the bleeding of the ***** cylinder. If not done exactly correct your clutch will not work no matter how much you bleed it. Bleeding the ***** cylinder, which is inside the transmission and not on the outside like older ones, relies more on gravity to bleed and not pumping. It's just a big pain in the ass actually and it will test your patience.
Source: by WooleyBugger

S5-42 Troubleshooting Guide for 87-91 BRONCO, F & E Series
Source: by Ford

S5-42 (7003) Parts Break-Out Diagram, Service Tips & Troubleshooting Guide; 07-03B-17 1994 Econoline / F-150, F-250, F-350 / Bronco / F-Super Duty Powertrain, Drivertrain Aug 1993
Source: by Ford

Cylinder Bleeding & Diagrams for Mazda M5R2 & ZF
Source: by Steve83

Here's the 1987 Bronco Dealer Brochure @ https://www.xr793.com/wp-content/uploads/2020/07/1987-Ford-Bronco.pdf

1987 Owner's Manual, partial (Towing it & 4 speed manual transmission shift patterns & operation) by Ford via member Mikey350 @ 1996 Ford Bronco 87 Bronco Owners Manual pictures, videos, and sounds | SuperMotors.net

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf found by BroncMom!

Good fortune!
Al

 

[johnnyreb]

Seems like alot of trouble and expense. Who not check on the older Fords . That had (has ) the 5 speed with 3 speed auxilary.

 

[Desertratt71382]

I did a 4speed(T-170RTS) to 5 speed(M5R2). The crossmember had to be moved floor had to be cut. The hydraulic clutch line and ***** cylinder had to be replaced as the 87 4speed has an external ***** cylinder while the M5R2 is internal. Honestly it was 2-18 hour full days to get it all to work. Then driveshafts don’t fit. So it’s a real headache. I’d advise against it.

 

[johnnyreb]

I am wanting to convert my granny low 4-speed to a 5-speed. I have a 1987 stock Bronco and since that year only came with 4-speed manuals, will a 5 -speed from a later model fit?? Is there many modifications? Should I convert the clutch to a hydraulic?

With all the expense,trouble running down parts and expense. It would be alot better going to higher gears --alot easier and alot cheaper. Also you need to address where it will be driven. In the town--changing gears all the time will get tiresome. On the interstate . Yes it could save gas,but also going to higher gear will also do the same thing. Plus you have the hassel getting the air bled from the hydraulic clutch and sometimes its not easy. If you want more--quicker power--lower gears can do that.

 

[chrlsful]

I know the EB better than ur model. The avatar shows 1, verbiage nother. Lucky U got stick now. One issue in the saga solved. For me? this is easier than getting some wiring issues done (poor understanding).

2 days would be w/o glitches. And a '2 short days' (4, 5 hrs each) would B on easy st (I had that w/my EB in signature). I'd do a 2 part research journey: .....1) every automotive Q is answrd by same "What is the application?". U want "st more'n trail". (MSOD from mazda in many ford trucks?...too light duty for hrd core rock crawlin). U want ZF for 2 PTOs and heavy duty (behind diesels)? U want....
2) instal methods. (all may require new X-member, some no DS length change - mine) hydro-clutch, frame drilling, etc?

Once these 2 Qs R answrd there's not much but budget choice & delivery v p/u...

 

[Ichblas]

Thanks guys! In running down all the parts and conversion of the current clutch to a hydraulic, sounds like lots of time